Identification and metagenetic characterisation of Listeria monocytogenes-harbouring communities present in food-related industrial environments Food Control (IF 3.667) Pub Date : 2018-07-18 Pedro Rodríguez-López, Marta Bernárdez, Juan J. Rodríguez-Herrera, Ángel S. Comesaña, Marta L. Cabo
The main aim of this study was to localise, identify and characterise the Listeria monocytogenes-harbouring bacterial communities present in food related premises via 16S rRNA gene metagenetic analysis. With this scope, 319 environmental samples coming from a wide variety of surfaces of fish (n = 120), meat (n = 80) and dairy industries (n = 119), were firstly analysed following ISO 11290–1 and ISO 11290–2 norms. Direct L. monocytogenes quantification was possible in 9 samples (2.8%) with values between 2.00 and 3.97 log CFU/cm2. After enrichment, an overall L. monocytogenes incidence of 12.54% (n = 40) was obtained, being samples from meat industry the most contaminated. Molecular serotyping assays showed that most of the isolates belonged to 1/2b-3b-7 subgroup, followed by 1/2a-3a and 1/2c-3c. These results combined with AscI and ApaI PFGE macrorestriction patterns, yielded 7 different L. monocytogenes clusters. Nevertheless, no clear ecological relationships could be stablished. High amounts of L. monocytogenes-associated psychrotrophic microbiota were obtained in all cases with values above 9 log CFU/cm2 in some cases. Metagenetic analysis of one representative sample per each food industry type (fish, meat, dairy) demonstrated that Actinobacteria (53.16%) was mostly present in the meat sample whereas Proteobacteria was the most representative phylum in dairy (69.58%) and fish (97.11%) samples. Subsequent operational taxonomic units (OTUs) analysis, showed a wide variety of taxa associated with L. monocytogenes such as spoilage-associated genera (e.g. Psyschromonas or Shewanella), lactic acid bacteria genera (e.g. Lactococcus or Lactobacillus) or pathogenic species such as Yersinia enterocolitica. It was thus demonstrated, that L. monocytogenes is capable to both survive with different bacteria in different ecological niches, highlighting once more the need for proper surveillance schedules so as to guarantee the safety of the food products.
Development of milk chocolate supplemented with microencapsulated Lactobacillus plantarum HM47 and to determine the safety in a Swiss albino mice model Food Control (IF 3.667) Pub Date : 2018-07-19 Reshma B. Nambiar, Periyar Selvam Sellamuthu, Anand Babu Perumal
Our study aimed to evaluate the survivability and safety of Lactobacillus plantarum HM47 strain supplemented in milk chocolate during storage and transit through gastrointestinal tract of mice. The milk chocolate was supplemented with microencapsulated Lactobacillus plantarum HM47 isolated from human breast milk. Water activity (aw), pH, and sensory attributes of the milk chocolates containing L. plantarum HM47 were analyzed. The HM47 were found to be viable up to 180 days of storage at 25°C (>8 log CFU/g) and the overall acceptability results suggested that the addition of probiotic had no significant effect (p>0.05) on the sensory attributes of the milk chocolate. An acute oral toxicity of the microencapsulated Lactobacillus plantarum HM47 in albino mice demonstrated no treatment related illness or mortality and feed consumption when compared to control mice. The 28 day administration of probiotic powder and probiotic milk chocolate to mice demonstrated that there was no observed adverse effect in the haematological parameters and vital organs of mice. Also the consumption of the probiotic powder and probiotic milk chocolate significantly (p<0.05) enhanced the intestinal lactic acid bacteria (LAB) count and suppressed the enteric pathogenic bacterial count in mice suggesting the colonization of HM47 in the intestine. Thus, the present study suggest that the milk chocolate could be used as a good carrier for probiotics and it can be established that Lactobacillus plantarum HM47 strain are safe and could be used as potential probiotic.
Development of detection method for edible silkworm (Bombyx mori) using real-time PCR Food Control (IF 3.667) Pub Date : 2018-07-19 Mi-Ju Kim, Seul-Ki Jung, Sung-Yeon Kim, Hae-Yeong Kim
The consumption of silkworms as edible insects has recently increased because of their good nutrition content. Many insect-based products are processed into a powder because of their unappetizing appearance. In this aspect, powdered silkworm has the possibility to be mixed with other insects. Thus, the development of a detection method for silkworm is necessary to provide accurate label information to consumers. In this study, we developed a real-time PCR assay using a TaqMan probe for detection of silkworm. The newly designed silkworm-specific primer pair and probe target the mitochondrial cytochrome oxidase subunit I (COI) gene. They were tested for their specificity using 15 insect species, and were confirmed to amplify only silkworm species. The limit of detection of this method was 0.001 ng of silkworm DNA, and as little as 1% of silkworm in two or more insect mixtures was detected. This developed method was applied to 30 processed foods including edible insects and was validated with four different real-time instruments. Therefore, the silkworm-specific real-time PCR assay may provide a specific and sensitive method for detection of silkworm in raw and processed foods.
Two-Step Washing with Commercial Vegetable Washing Solutions, and Electrolyzed Oxidizing Microbubbles Water to Decontaminate Sweet Basil and Thai Mint: A Case Study Food Control (IF 3.667) Pub Date : 2018-07-19 Pitirat Klintham, Sasitorn Tongchitpakdee, Wannee Chinsirikul, Warapa Mahakarnchanakul
A study was conducted on pre-washing vegetables with four different kinds of surfactant in the washing solution, followed by an acidic electrolyzed oxidizing microbubbles water (AEO-MB) to compare their efficacy on the decontamination of E. coli and S. Typhimurium on sweet basil and Thai mint. Three commercial surfactants (0.1% v/v) and Tween 80® were applied in pre-washing with a constant rate of shaking at 60 rpm for 3 min, then washed with 40 mg/L of AEO, oxidation reduction potential (ORP) 1,130-1,180 mV and pH 2.8-3.1, under the continuous generation of MB for 5 min. All surfactants showed no antimicrobial activity but greater decontamination (99.0-99.9%) was observed when two-step washing was applied. Wash water with AEO indicated the absence of microorganisms thus helping to prevent cross-contamination. Our study revealed that pre-washing helped to improve the washing efficacy and to enhance the food safety of sweet basil and Thai mint and the treatment may be suitable for application with household or commercial ready-to-eat produce.
Elemental analysis of sea cucumber from five major production sites in China: A chemometric approach1 Food Control (IF 3.667) Pub Date : 2018-07-17 Xuming Kang, Yanfang Zhao, Derong Shang, Yuxiu Zhai, Jinsong Ning, Xiaofeng Sheng
Geographic origin of sea cucumber is topic of interest for both consumers and producers since the prices of sea cucumber vary largely according to their geographic origins. It is currently important that a scientific technique should be developed for determining geographic origin as a mean to detect fraudulent labeling. We have therefore developed a technique to classify the geographic origin of sea cucumber based on elemental analysis combined with the statistical analysis. In this study, a total of 39 elements contents of sea cucumber from five major production regions in China were determined to evaluate their applicability in the origin traceability of sea cucumber. Pattern recognition techniques including principal component analysis (PCA) and linear discriminate analysis (LDA) were applied to evaluate their performance in terms of classification or predictive ability. Thirty six elements in sea cucumber samples of different regions showed significant differences (p<0.05), which proved that the elemental composition was an effective tool for distinguishing different origins of sea cucumber. Classification of sea cucumber using PCA did not give satisfactory results. The LDA gave an overall correct classification rate of 94.1% and cross-validation rate of 88.2%. These results demonstrated the usefulness of multi-element fingerprints as indicators for authenticating the geographical origin of sea cucumber in China.
Antimicrobial activity and mechanism of action of olive oil polyphenols extract against Cronobacter sakazakii Food Control (IF 3.667) Pub Date : 2018-07-17 Peng Fei, Md. Aslam Ali, Shaoying Gong, Qi Sun, Xue Bi, Sifan Liu, Ling Guo
This study was conducted to analyze the antimicrobial activity of olive oil polyphenols extract (OOPE) against Cronobacter sakazakii. The antimicrobial effect was evaluated by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values, and survival of bacteria after treatments with OOPE in sterile normal saline (NS) and Luria-Bertani (LB) broth. The changes in intracellular ATP concentration, cell membrane potential, content of bacterial protein, and cell morphology were analyzed to reveal possible mechanism of action. The results showed that the MICs and MBCs of OOPE against C. sakazakii strains ranged from 0.625 to 1.25 mg/mL, and 1.25 to 2.50 mg/mL, respectively. Approximately 8 log CFU/mL of C. sakazakii was completely inactivated after a treatment with 1 MIC of OOPE in NS at 37°C for 3 h, and in LB broth at 37°C for 10 h. The mechanism of action of OOPE against C.sakazakii was associated with reduction of intracellular ATP concentrations, cell membranes depolarization, leakage of cytoplasm, decrease of bacterial protein content and leakage of cytoplasm. Therefore, our findings provided a theoretical possibility that OOPE can be used as a natural food preservative or bactericide to reduce the food safety problems caused by C. sakazakii strains in food industries as well as food processing environments.
Enzymatic dispersal of dual-species biofilms carrying Listeria monocytogenes and other associated food industry bacteria Food Control (IF 3.667) Pub Date : 2018-07-17 C.H. Puga, P. Rodríguez-López, M.L. Cabo, C. SanJose, B. Orgaz
Enzyme-based treatments could therefore be used to complement regular cleaning processes. Most studies using enzymes as anti-biofilms strategy are focused on their outcome in mono-species biofilms. Nevertheless, in real environments mixed biofilms are prevalent. In this work, seven types of dual-species biofilms were selected to serve as targets for enzymatic treatments carrying different environmental strains of L. monocytogenes and accompanying bacteria isolated from dairy, meat and seafood processing plants. The effectiveness of nine commercial enzymatic preparations, including pronase, cellulase, pectinase, DNase I, lysozyme, phospholipase, peroxidase, β-glucanase and chitinase, was evaluated. For this, residual attached viable cells of both L. monocytogenes and its partners were enumerated through swabbing and colony plate counting following the action of each enzyme. Moreover, Confocal Laser Scanning Microscopy (CLSM) images were analyzed pre and after enzymatic treatments in order to quantify changes in biofilm thickness, covered area and volume. The viable attached population of L. monocytogenes was almost unaffected by all of the enzymes here tested, being eliminated on average just the 90% of the initially attached population (around 1 Log10 cfu cm−2 reduction). Nevertheless, some of the partner species (Escherichia coli and Staphylococcus saprophyticus) were sometimes protected from enzymatic detachment when in dual-species biofilms, depending on the enzyme tested and the accompanying L. monocytogenes strain. CLSM images showed important changes in biofilm covered area and volume after DNase I, pronase and pectinase treatments. These results demonstrate that enzymes can greatly weaken dual-species biofilms structure. Nevertheless, it cannot be disregarded that detached cells from these treatments would still be viable. Thus, a control of cell viability after an enzymatic procedure in the food industry must be always considered before designing an efficient disinfection treatment.
A comparison between NIR and ATR-FTIR spectroscopy for varietal differentiation of Spanish intact almonds Food Control (IF 3.667) Pub Date : 2018-07-17 Victoria Cortés, José Manuel Barat, Pau Talens, José Blasco, María Jesús Lerma-García
The rapid and easy classification of almond varieties with similar morphology, different quality properties and, in most cases, different prices is interesting to protect both the almond industry and the consumers from fraud. Therefore, in this work, intact almond kernels from four Spanish varieties (‘Guara’, ‘Rumbeta’, ‘Marcona’ and ‘Planeta’) were analysed using both near infrared (NIR) and attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy. After spectra measurement, NIR and ATR-FTIR spectral data were pre-treated and employed to construct two classification methods (partial least square-discriminant analysis (PLS-DA) and quadratic discriminant analysis (QDA)) in order to check their ability to classify almonds according to their variety. The best overall accuracies (94.45%) were obtained with the PLS-DA model of ATR-FTIR and the QDA model of NIR data. These results confirm that both spectroscopic techniques, if the optimal statistical model is selected, are powerful tools to reliably discriminate almonds according to their varieties.
Development of an automated method for the identification of defective hazelnuts based on RGB image analysis and colourgrams Food Control (IF 3.667) Pub Date : 2018-07-17 A. Giraudo, R. Calvini, G. Orlandi, A. Ulrici, F. Geobaldo, F. Savorani
Over the past decades, Red-Green-Blue (RGB) image analysis has gained increasing importance in industrial applications, since it has widely proved to be a suitable tool for food quality and process control. This article describes the development of a fast and objective method for the automated identification of defective hazelnut kernels based on multivariate analysis of RGB images. To this aim, an overall sample set of 2000 half-cut hazelnut kernels, previously assigned by industrial expert assessors as sound or defective (i.e. rotten or pest-affected), was collected and imaged using a digital camera. The colour-related information of the images was converted into one-dimensional signals, named colourgrams, which were firstly explored through the Principal Component Analysis and subsequently used to build classification models, based on both Partial Least Square-Discriminant Analysis (PLS-DA) and interval-PLS-DA (iPLS-DA) algorithms. A tree-structure hierarchical classification approach has been considered, i.e. the discrimination between sound and defective kernels as a first rule, and the discrimination between the two types of defect as a second rule. The best sound vs defective classification model was able to correctly recognize approximately the 97% of the test set defective samples, while the best rotten vs pest-affected model allowed classifying correctly more than 92% of the test set samples. Moreover, the image reconstruction performed using the selected colourgram features led to an exhaustive interpretation of the decision-making criteria adopted by the classification algorithms and further confirmed the reliability of the proposed method.
Antimicrobial susceptibility of bifidobacteria from probiotic milk products and determination of the genetic basis of tetracycline resistance in Enterococcus species after in vitro conjugation with Biﬁdobacterium animalis subsp. lactis Food Control (IF 3.667) Pub Date : 2018-07-12 Shahram Naghizadeh Raeisi, Hamid B. Ghoddusi, Erik Juncker Boll, Nasim Farahmand, Birgitte Stuer-Lauridsen, Eric Johansen, Jane P. Sutherland, Labia Irène I. Ouoba
The study aimed at investigating the antimicrobial resistance (AMR) profiles of bifidobacteria from fermented milks sold in the UK that are claimed to have beneficial effects on humans, and assess the potential transferability of AMR to other bacteria.Isolates of different Bifidobacterium species were screened for their susceptibility to 24 antimicrobials and the presence of AMR genes [tet(M), tet(L), tet(S), tet(Q), tet(K), tet(O), tet(W), aph(3’’)-I, ant(2’’)-I, aph(3’’)-III, strA, strB, aadA, aadE, erm(A), erm(B), and erm(C)]. The ability of Bifidobacterium animalis ssp. lactis isolates to transfer the tet(W) gene to Enterococcus faecalis JH2-2 and Enterococcus faecium BM4105 was investigated by conjugation. Potential E. faecalis transconjugants (PETs) were analysed by whole genome sequencing (WGS) for the presence of tet(W), other DNA fragments from the donor and single-nucleotide polymorphisms (SNPs). A high level of resistance to aminoglycosides and a moderate level of resistance to tetracycline were observed, while susceptibility to macrolides, vancomycin, chloramphenicol and beta-lactams was determined. Only the tet(W) gene was detected in all B. animalis ssp. lactis isolates. Some PETs exhibited a significant tetracycline MIC increase from 1 to up to 16 mg/L. WGS did not detect tet(W) in the PETs, but SNPs in the rpsJ gene encoding the ribosomal protein S10, which is part of the 30S ribosomal subunit and contains a proposed tetracycline binding site. Substitutions (Tyr-58→Asp, Tyr-58→Cys, Asp-60→Tyr, Tyr-58→Ser, Ser-61→Tyr, Ala-54→Glu, Asp-60→Tyr) and an insertion of Thr between Thr55 and His56 were detected. No E. faecium transconjugants were recovered.B. animalis ssp. lactis isolates did not transfer the tet(W) gene to the Enterococcus species. The majority of the PETs had mutations within or near the ribosomal protein S10 vertex loop suggesting that mutations in the rpsJ gene confer tetracycline resistance to E. faecalis JH2-2.
Low false response rates in screening a hundred veterinary drug residues in foodstuffs by LC-MS/MS with analyte-specific correction of the matrix effect Food Control (IF 3.667) Pub Date : 2018-07-12 Thierry Delatour, Marie-Claude Savoy, Adrienne Tarres, Thomas Bessaire, Pascal Mottier, Aurélien Desmarchelier
As a response to the demand for better efficiency and reliability in the monitoring of veterinary drug residues in food, liquid chromatography-mass spectrometry (LC-MS), either in tandem with quadrupoles (LC-MS/MS) or with high resolution systems (LC-HRMS), has become an attractive tool for screening purposes. However, the lack of reproducibility of the ionization yield observed by electrospray remains a major limitation for having powerful LC-MS platforms able to screen more than a hundred substances in a broad range of food on a reliable manner. False responses are not scarce, and require insightful approaches to mitigate them. This study describes a screening with analyte-specific correction of the matrix effect (SACME), as a strategy based upon the comparison of the chromatographic signals between the sample analyzed ‘as is’ and a replicate that has preliminarily been spiked at the action level. Emphasis was put on the high level of confidence in the results achieved with SACME, providing a self-quality control of each sample tested. The significant decrease in the variability of the responses compared to a screening with absolute abundance (SAA) of the signals is shown, and the perspective of screening a wide range of food matrices (raw materials, processed ingredients and finished products) without tedious technical precautions is highlighted. In the end, false response rates are compared, and data demonstrate unambiguously the benefit of the matrix effect attenuation against the common approach using absolute areas. No false positive (FP) was obtained with SASAME, whilst a minimum of 2 to 14 compounds (over 105 substances in the scope of the method) exhibited false positive responses with SAA. With SACME, false negative (FN) rates as low as 1 to 5 compounds were obtained, whilst remained in the range 15 – 31 compounds with SAA.
Organic and conventional coffee differentiation by NMR spectroscopy Food Control (IF 3.667) Pub Date : 2018-07-12 R. Consonni, D. Polla, L.R. Cagliani
The present study reports the application of 1H NMR profiling for the differentiation of organic and conventional Coffea arabica roasted coffee samples. NMR data of coffees with different geographical origins have been analyzed by chemometrics for a possible metabolite differentiation. Classification methods like OPLS-DA allowed to highlight fatty acids, β-(1-3)-d-galactopyranose, β-(1-4)-d-mannopyranose, quinic acid and its cyclic ester as the characteristic metabolite for organic coffee, while trigonelline, CGA isomers, caffeine and acetate for conventional ones. The use of Orthogonal Signal Correction (OSC) filters improved the samples differentiation confirming fatty acids, β-(1-3)-d-galactopyranose, quinic acid and its cyclic ester as the major metabolites characterizing organic roasted coffee, while conventional resulted enriched in trigonelline and CGA isomers. The preliminary data here presented indicated 1H NMR spectroscopy as a valid method for farming differentiation of C. arabica roasted coffee.
Antimicrobial mechanism of clove oil on Listeria monocytogenes Food Control (IF 3.667) Pub Date : 2018-07-11 Haiying Cui, Chenghui Zhang, Changzhu Li, Lin Lin
Although clove oil is widely used in food preservation, very little is known about its possible antibacterial mechanism. In order to reveal its antibacterial mechanism, the inhibitory effect of clove oil on Listeria monocytogenes and its effect on cell membrane, respiratory metabolism, and its interaction with DNA were investigated, respectively. The results showed the treatment of clove oil can cause the leakage of three biological macromolecules (protein, ATP and DNA) and the reduction of two intracellular enzymes (β-galactosidase and AKP) activities, indicating that clove oil has an effect on cell membrane permeability. The inhibition rate and superposition rate test confirmed that the pathway of clove oil affecting the respiratory metabolism of Listeria monocytogenes is TCA pathway. The treatment of clove oil can reduce the activity of three key enzymes (isocitrate dehydrogenase, citrate synthase and α-ketoglutarate dehydrogenase) in TCA pathway, and affect the content of metabolites in the pathway. The results of ultraviolet absorption spectroscopy showed that eugenol, the main component of clove oil, can change the structure of DNA via the formation of eugenol-DNA chimera.
Antibacterial effect and mechanism of anthocyanin rich Chinese wild blueberry extract on various foodborne pathogens Food Control (IF 3.667) Pub Date : 2018-07-11 Xiao-hong Sun, Tong-tong Zhou, Cai-hong Wei, Wei-qing Lan, Yong Zhao, Ying-jie Pan, Vivian C.H. Wu
Anthocyanins of wild blueberries were studied for the inhibition of the growth of Listeria monocytogenes, Staphylococcus aureus, Salmonella enteritidis and Vibrio parahaemolyticus. The inhibitory mechanisms of anthocyanins from Chinese wild blueberries were also evaluated. Vibrio parahaemolyticus was the most susceptible to anthocyanins with the lowest MIC/MBC for each treatment, followed by St. aureus. After a treatment of anthocyanins, the membrane permeability and metabolism of four pathogens were assessed. The whole protein content and the activity of alkaline phosphatase, adenosine triphosphatase and superoxide dismutase were measured by several protein assay kits. When foodborne pathogens were treated with anthocyanins for 2 h, the nucleic acid leakage and protein releaseincreased, which demonstrated that anthocyanins could destroy the cell membrane. Furthermore, the whole protein content and enzyme activity decreased after treatment. With an increasing concentration of anthocyanins, the production rate of formazan by L. monocytogenes, St. aureus, S. enteritidis, V. parahaemolyticus decreased by 55%, 71%, 67% and 79%, respectively. This inferred that the TCA cycle was decreased, reducing the energy transfer of pathogens thus inhibiting their growth and reproduction. The strong antimicrobial effect of Chinese wild blueberry anthocyanins provides application potential in the field of food safety.
Antibacterial activity of gallic acid against Shigella flexneri and its effect on biofilm formation by repressing mdoH gene expression Food Control (IF 3.667) Pub Date : 2018-07-09 Jiamu Kang, Liu Liu, Meihui Liu, Xiaoxia Wu, Jianke Li
Persistent bacterial infections caused by biofilm- associated Shigella spp. are a global public health concern. The following study aims to determine the antibacterial activity and possible mechanism that gallic acid (GA) displays against Shigella flexneri (Sh. flexneri) and its effect on the biofilm formation. The minimum inhibitory concentration (MIC) and the minimal bactericidal concentration (MBC) values that GA exhibited against planktonic Sh. flexneri were 2 mg/mL and 8 mg/mL. The time-kill curves showed that the concentration and the treatment time of GA led to inhibitory effects, which was evidenced by reduced cell viability, destroyed cell membranes, and changes in the bacterial morphology. GA was shown to have a significant inhibition effect on the Sh. flexneri biofilm formation and infiltrated into the EPS, which reduced the number of viable bacteria. Further studies showed that the expression of the mdoH gene and the OpgH protein was inhibited in the Sh. flexneri biofilm cells. The polysaccharide contents in the biofilm decreased. The results suggested that GA effectively inhibited planktonic Sh. flexneri activity and its biofilm formation by regulating the expression of the mdoH gene and the OpgH protein. These findings indicated that GA has potential use as a natural and a safe alternative for controlling the growth of the Sh. flexneri biofilm.
Development of Finger Citron (Citrus medica L. var. sarcodactylis) essential oil loaded nanoemulsion and its antimicrobial activity Food Control (IF 3.667) Pub Date : 2018-07-09 Ze-hua Li, Ming Cai, Yuan-shuai Liu, Pei-long Sun
In this work, various surfactants and cosurfactants were selected to develop nanoemulsions of finger citron essential oil (FCEO). Five suitable mixtures of surfactants were obtained: Cremophor EL/1, 2-propanediol (1:1, m/m), Cremophor EL/glycerol (1:1, m/m), Tween 80/ethanol (3:2, m/m), Tween 80/PEG-400 (3:2, m/m) and Tween 80/1, 2-propanediol (3:1, m/m). These five nanoemulsions showed a good stability with average droplet sizes kept below 20 nm for at least 28 days. All of them had low polydispersity index. Antimicrobial activities of these five nanoemulsions against bacteria (E. coli, B. subtilis and S. aureus) and molds (A. niger and P. citrinum) were tested, in which the nanoemulsion with Cremophor EL enhanced the antibacterial ability. However, the antifungal activities of these nanoemulsions were weaker than expected. These developed FCEO loaded nanoemulsions have good physical stability and antibacterial activity, suggesting their potential application in food and beverage fields.
Techniques for Insect Detection in Stored Food Grains: An Overview Food Control (IF 3.667) Pub Date : 2018-07-09 Km.Sheetal Banga, Nachiket Kotwaliwale, Debabandya Mohapatra, Saroj Kumar Giri
Insects cause a major loss in stored food grains. Besides, pestilential activities of insects in stored food grains affect the marketability as well as the nutritional values. Early detection and monitoring of insects in the stored food grains become necessary for applying corrective actions. Visual inspection, probe sampling, insect trap, Berlese funnel, visual lures, pheromone devices etc., are some of the popular methods largely used in commercial granaries or grain storage establishments. Of late, electronic nose, solid phase micro-extraction, thermal imaging, acoustic detection, etc. have been reported to be successful in detecting insects. The capability of in-situ early detection, monitoring, cost, reliability, and labor requirements are the major factors considered during for selection of the method. Detection of hidden infestation, whose population may be many times higher than the free-living insects is an important concern to mitigate the losses in bulk storage warehouses, so as to enable the early actions for fumigation or to dispose off the grain. This paper reviews some of the widely used detection methods for early detection of insects’ pestilential activities in stored food grains as well as some of the novel technologies with an emphasis on acoustic method, which has a good commercial potential.
Quantification of TMA in fishery products by direct sample analysis with high resolution mass spectrometry Food Control (IF 3.667) Pub Date : 2018-07-07 Giovanna Esposito, Simona Sciuto, Pier Luigi Acutis
Seafood freshness is a quality key parameter due to the short shelf life of this highly perishable foodstuff in relation to safety, nutritional value, availability, and edibility. A variety of physical, microbiological, and chemical methods are used for assessing and predicting seafood quality. Chemical analyses to assess seafood freshness quality are based on the determination of substances like volatile amines that are structurally similar to ammonia and responsible for the fishy odour fish give off several days after catch.Here we report the results of a method to detect and quantify trimethylamine (TMA) by means of direct sampling analysis (DSA) coupled with a high-resolution mass spectrometer with a time of flight detector (TOF).Three different seafood products, Sea bream (Sparus aurata), Octopus (Octopus vulgaris), and Red mullet (Mullus barbartus) purchased fresh from a wholesale fish market (Savona, Ligurian Sea, Italy) were analyzed. The TMA adduct was correctly identified in all samples. Monitoring of TMA levels in the wholesale products from day 0 to day 20 showed an increase in all samples, confirming deterioration of freshness quality.This innovative, simple, and rapid method may prove useful for routine screening analysis and holds promise as a tool to evaluate seafood freshness quality and protect consumers from potential health risks.
The Effects of Grapefruit Seed Extract on the Thermal Inactivation of Listeria monocytogenes in Sous-vide Processed Döner Kebabs Food Control (IF 3.667) Pub Date : 2018-07-07 Güliz Haskaraca, Vijay K. Juneja, Sudarsan Mukhopadhyay, Nuray Kolsarici
The heat resistance (57.5 to 65°C) of Listeria monocytogenes in vacuum packaged, cook-in-bag, döner kebabs that included 0.5 or 1% grapefruit seed extract (GSE) was determined. The packages were processed to an internal temperature of 57.5, 60, 62.5 or 65°C in 1 h, held for a predetermined period of time, and then, ice chilled. The surviving cell population was determined by plating diluted samples onto tryptic soy agar overlaid with 10 ml of modified Oxford agar. Survivor curves were fitted to an equation based on the Weibull distribution using the USDA Integrated Pathogen Modeling Program 2013 software tool. The Weibull model consistently offered more accurate fit to all survivor curves based on the smaller root mean square error (< 0.46). The times to 4-log reduction were 140, 62.38, 14.45 and 6.84 min at 57.5, 60, 62.5, and 65°C, respectively. Supplementing döner kebab with 0.5 – 1% GSE rendered the pathogen more sensitive to the lethal effect of heat. The results provide the food industry with an option to supplement 0.5 – 1% GSE in sous vide processed döner kebab, that ensures adequate degree of protection against L. monocytogenes and at the same time, provide energy conservation and quality products.
Improved antimicrobial activity of immobilised essential oil components against representative spoilage wine microorganisms Food Control (IF 3.667) Pub Date : 2018-07-07 Estéfani García-Ríos, María Ruiz-Rico, José M. Guillamón, Édgar Pérez-Esteve, José M. Barat
Wine, as a fermented drink, is considered a microbiologically safe beverage, but the growth of spoilage microorganisms can cause economic damage. As a new preservative process, the application of immobilised essential oil components (EOCs) is proposed in this study. EOCs were attached to the surface of three different commercial supports (silica particles, cellulose particles and cellulosic membrane) to avoid the disadvantages of using these compounds in their free form, such as volatility, low water solubility and intense aroma. The results showed that the treatment of spoilage microorganisms with antimicrobial particles (silica and cellulose) significantly reduced the viability and growth capacity of the target microorganisms. The covalent attachment of EOCs to particles led to a significant reduction in both the MIC values and viability compared with most free compounds. The enhanced antimicrobial activity of EOCs after their anchorage to a support was confirmed, resulting in MIC values of 10–90 fold lower than those of the free bioactive compounds. In addition, the filtration of microorganism suspensions through EOC-functionalised membranes showed remarkably antimicrobial activity.
Stress resistance, motility and biofilm formation mediated by a 25kb plasmid pLMSZ08 in Listeria monocytogenes Food Control (IF 3.667) Pub Date : 2018-07-04 Hui Zhang, Yunhe Hu, Chenglu Zhou, Zhenquan Yang, Litin Wu, Mengya Zhu, Hongduo Bao, Yan Zhou, Maoda Pang, Ran Wang, Xiaohui Zhou
Listeria monocytogenes is a foodborne pathogen that can form biofilm and tolerate severe environment condition and thus persist in food product for a prolonged period, which poses a significant risk to food safety. While some chromosomal genetic determinants associated with stress resistance and biofilm formation have been characterized, plasmid-mediated stress resistance in particular L. monocytogenes strains are less known. In this study, we showed a L. monocytogenes strain SZ08 (serovar 1/2b) isolated from a raw meat processing environment harbored a 25kb plasmid, designated as pLMSZ08. After incubation under the selective condition containing novobiocin, pLMSZ08 was successfully cured from SZ08. Compared to its parental strain SZ08, the cured strain SZ08* was not able to grow well under the high concentration of sodium chloride (5.5%). SZ08* displayed higher efficiency of plaque formation compared with its parental strain SZ08. There were no significant growth difference under different temperature and pH conditions between SZ08 and SZ08*. Biofilm formation of SZ08* reduced significantly compared with SZ08 after 48hr incubation. Furthermore, the relative expression levels of flagella-associated genes in SZ08* were up-regulated comparing to those in SZ08. We have sequenced the pLMSZ08 and the sequencing results showed that pLMSZ08 harbors genes associated with transcriptional regulation, metal/drug transport, histidine kinase and ATPase. These results suggested that these genes encoded by pLMSZ08 are associated with tolerance, motility and biofilm formation in L. monocytogenes SZ08.
Evaluation of Roka Atlas Salmonella method for the detection of Salmonella in egg products in comparison with culture method, real-time PCR and isothermal amplification assays Food Control (IF 3.667) Pub Date : 2018-07-03 Lijun Hu, Xiaohong Deng, Eric W. Brown, Thomas S. Hammack, Li M. Ma, Guodong Zhang
With the increasing focus on the food safety, rapid methods for the detection of Salmonella are crucial for both food industry and regulatory agencies. Recently, many molecular methodologies with diverse technologies have been introduced. Roka Atlas®Salmonella Assay (SEN) is a molecular method that uses ribosomal RNA as target for detection, which is theoretically more sensitive than PCR or isothermal amplification methods that target the DNA sequences of single genes. In this study, SEN assay was compared with 4 PCR- and isothermal amplification-based assays and a culture method, such as the MicroSEQ®Salmonella spp. Detection kit (MicroSEQ), 3M™ Molecular Detection Assay (MDA) Salmonella, ANSRTMSalmonella Assay (ANSR), and Pro-AmpRTTM SALM spp. Kit (Pro-AmpRT). Food samples were prepared and analyzed according to the current U. S. Food and Drug Administration (FDA) Bacteriological Analytical Manual (BAM) Salmonella culture method. A total of 155 bacterial isolates (121 for Salmonella inclusivity and 34 for Salmeonlla exclusivity) and 200 egg product samples inoculated at a level of 1–5 CFU/25 g were analyzed. The study also estimated the limit of detection of these molecular methods, and illustrated their advantages and disadvantages. For exclusivity, all 34 non-Salmonella isolates were negative by all 5 molecular methods studied. For inclusivity, all 121 Salmonella isolates were positive by MDA, ANSR, and Pro-AmpRT methods. However, the SEN and MicroSEQ results were negative for 9 samples inoculated with Salmonella bongori. The detection limit of the 5 molecular methods ranged from 0.38 to 3.76 log CFU/mL pre-enrichment culture, with the SEN assay being the most sensitive (0.38–2.64 log CFU/mL). The results indicated that the SEN assay was as effective and sensitive in detecting Salmonella enterica in egg products as was the FDA BAM culture method and the 4 other isothermal amplification and PCR methods evaluated in the study.
Assessing farmers market produce vendors’ handling of containers and evaluation of the survival of Salmonella and Listeria monocytogenes on plastic, pressed-card, and wood container surfaces at refrigerated and room temperature Food Control (IF 3.667) Pub Date : 2018-07-02 KaWang Li, Hanna Khouryieh, Lisa Jones, Xiaoli Etienne, Cangliang Shen
This study aims to assess how small produce growers handle containers and evaluate the survival of Salmonella and Listeria monocytogenes on various produce container surfaces commonly used at farmers markets, under storage conditions both at refrigerated and room temperature. In Study I, an anonymous survey was conducted to assess the practices of handling produce containers from 28 vendors at farmers markets in Morgantown, WV and 141 vendors from farmers markets in Kentucky. In Study II, plastic, pressed-card, and wood containers were trimmed (25 cm2) and inoculated with S. typhimurium and Tennessee, and two strains of L. monocytogenes, stored at 3.2 °C (22.19% RH) and 22.5 °C (50.40% RH), respectively, for 21 days and periodically analyzed for microbial populations on XLT-4 (Salmonella) and Modified-Oxford (L. monocytogenes) agars. The survey results showed that plastic, paper, and wood containers are the top three choices for small produce growers to transport and present produce at farmers markets. The pathogens decreased slower (P < 0.05) at 3.2 °C and on pressed-card and wood surfaces than at 22.5 °C and on a plastic surface. At 3.2 °C, Salmonella counts decreased (P < 0.05) from 5.27 to 5.53 to 2.63–2.84 log CFU/cm2, and L. monocytogenes decreased (P < 0.05) from 6.39 to 6.93 to 4.89–5.46 log CFU/cm2 on the three material surfaces by the end of the storage period, with the lowest (P < 0.05) survival on a plastic surface. At 22.5 °C, Salmonella populations decreased (P < 0.05) from 4.94 to 5.38 to <1.30 log CFU/cm2 (the detection limit) after 3, 9 and 12 days on plastic, pressed-card and wood surfaces, respectively. L. monocytogenes decreased (P < 0.05) from 6.39 to 6.93 to ≤1.30 log CFU/cm2 after 12, 12, and 21 days on plastic, wood and pressed-card surfaces, respectively. These results were confirmed by different mathematical survival models for analyzing pathogen inactivation rates. Vendors at farmers markets should choose plastic containers to store fresh produce and avoid storing containers at refrigerated temperature.
A new single-tube platform of melting temperature curve analysis based on multiplex real-time PCR using EvaGreen for simultaneous screening detection of Shiga toxin-producing Escherichia coli, Salmonella spp. and Listeria monocytogenes in food Food Control (IF 3.667) Pub Date : 2018-07-02 Bundidamorn Damkerng, Supawasit Wannakarn, Trevanich Sudsai
Shiga toxin-producing Escherichia coli (STEC), Salmonella spp. and Listeria monocytogenes are continuously reported as causative agents of great concern regarding food safety and widespread contamination in many food varieties. Therefore, their simultaneous detection may be advantageous in terms of cost, time and labor savings and simplicity. This study developed a new, simple platform of multiplex real-time polymerase chain reaction (mRT-PCR) for specific, sensitive and rapid detection of STEC, Salmonella spp. and L. monocytogenes in food. The single-tube mRT-PCR format was developed by combining an 18 h enrichment step in simultaneous enrichment broth, boiling based on DNA extraction assay and a mRT-PCR detection system based on melting curve analysis using a fluorescent dye (EvaGreen) for detection of the presence or absence of the three target bacterial pathogens in food samples. Three specific peaks were clearly detected with average melting temperatures of 84.5 ± 0.90 °C, 87.5 ± 0.54 °C and 79.3 °C ± 0.48 °C for STEC, Salmonella spp. and L. monocytogenes, respectively. The sensitivity and specificity of these newly developed mRT-PCR platforms were further investigated using artificially and naturally contaminated food samples. The relative sensitivity, relative specificity and relative accuracy were all 100%, with a detection limit of 1 cfu for each target pathogen in 25 g of food sample. The developed platform of EvaGreen-based single-tube mRT-PCR for detection of the three target pathogenic bacteria in food samples provided results of absence or presence within 20 h. The newly developed mRT-PCR platform in this study offers a promising approach for simple, rapid, sensitive, specific and accurate detection of the three target bacterial pathogens in food.
Interactions of aflatoxin B1 and related secondary metabolites with native cyclodextrins and their potential utilization Food Control (IF 3.667) Pub Date : 2018-06-30 Qifang Wu, Jun Xu, Huirong Xu
Quaternary ammonium compounds with multiple cationic moieties (multiQACs) provide antimicrobial activity against Campylobacter jejuni ☆ Food Control (IF 3.667) Pub Date : 2018-06-30 Nereus W. Gunther IV, Aisha Abdul-Wakeel, Erin R. Reichenberger, Saleh Al-Khalifa, Kevin P.C. Minbiole
Recently developed quaternary ammonium compounds (QACs) possessing multiple cationic moieties, referred to as multiQACs, were tested with strains of Campylobacter jejuni to determine their potential as antimicrobial compounds against this important foodborne pathogen. Eight multiQACs were tested against a cocktail of six C. jejuni strains isolated from environmental and clinical sources. The resulting reductions in C. jejuni numbers mediated by the multiQACs were compared to the reductions produced by the application of four commercially available QACs, each of which bears a single cation. Multiple concentrations and exposure times were utilized for all compounds. The compounds which yielded the maximum C. jejuni reductions at the lowest concentrations and applied over the shortest exposure times were judged to be the most successful. Of the eight multiQACs investigated, four demonstrated reductions in C. jejuni numbers superior to the commercial QACs; these four are biscationic, and two of them bear an additional uncharged nitrogen atom. The remaining four multiQACs, which contain three or four cations, did not produce reductions in bacterial numbers comparable to commercial QACs in the timeframes tested. At the intermediary compound concentration (0.05 mM) and exposure time (5 min) the most effective multiQACs (PQ-12,12 and 12(3)0(3)12) on average killed over 99% of the Campylobacter cells present while the best commercial compound at those parameters (cetyl pyridinium chloride, CPC) only killed on average 84.56% of the Campylobacter cells. At the highest compound concentration tested (0.1 mM) and shortest exposure time (1 min), the same two biscationic multiQACs averaged mean percent reductions of Campylobacter cell numbers around 99.5% while CPC at the same concentration/exposure only managed a percent reduction of 91.3%. The biscationic multiQACs demonstrate the potential for providing a new group of antimicrobial compounds superior to current commercially available QACs in their effectiveness against C. jejuni.
Survival of Salmonella on Raw Poultry Exposed to 10% Lemon Juice and Vinegar Washes Food Control (IF 3.667) Pub Date : 2018-06-30 Shauna C. Henley, Natalie Launchi, Jennifer J. Quinlan
The widespread practice of washing raw poultry has been the target of multiple consumer education campaigns in recent years. In addition to rinsing with plain water, a subset of consumers report using acidic solutions (diluted lemon/lime juice or vinegar) to wash raw poultry. While studies have demonstrated the ineffectiveness of acidic marinades to eliminate pathogens from raw meat, the effect of acidic washes on raw poultry has not previously been examined. The research reported here determined the fate of Salmonella enterica 19214 inoculated onto raw poultry and subsequently exposed to acidic washes. Chicken breasts were inoculated with approximately 5 x 108 CFU of Salmonella enterica 19214 (resistant to tetracycline, streptomycin and chloramphenicol). Inoculated breasts were then washed for 10 seconds, 30 seconds, 2 minutes or 5 minutes in control (tap water) or acidic (10% vinegar or 10% lemon juice) solutions to simulate consumer washing. Following washing, S. enterica 19214 levels were determined both in the wash water and on the chicken using media containing antibiotics. Washing with 10% vinegar (pH 3.1) resulted in the recovery of 7.23 to 7.46 log CFU/ml S. enterica from the chicken and 6.63 to 6.73 log CFU/ml S. enterica from the vinegar wash solution. Washing with 10% lemon juice (pH 2.6) resulted in the recovery of 7.26 to 7.42 log CFU/ml from the chicken and 6.28 to 7.06 log CFU/ml from the lemon juice wash. Results indicate that acidic washes result in live Salmonella both in the wash as well as remaining on the chicken. Washing raw poultry in a diluted lemon juice or vinegar solution is an inefficient method for removing pathogens and results in pathogens both in the wash water and on the chicken, increasing the risk for cross contamination and potential foodborne illness.
Factors Affecting the Performance and Monitoring of a Chlorine Wash in Preventing Escherichia coli O157:H7 Cross-Contamination during Postharvest Washing of Cut Lettuce Food Control (IF 3.667) Pub Date : 2018-06-30 Tong-Jen Fu, Yichen Li, Deena Awad, Ting-Yang Zhou, Lyurui Liu
This study examined factors that may affect the performance of a produce wash in preventing E. coli O157:H7 cross-contamination. Fresh-cut romaine lettuce (8 or 20 g) inoculated with ca. 7 log CFU/g of E. coli O157:H7 expressing green fluorescence protein was washed with uninoculated cut lettuce (800 or 2000 g) in 40 L of water for 2 min. Washing trials were performed in both sterile tap water and spent wash water collected from a commercial leafy greens processing facility under different prewash free chlorine levels (0, 5, 20 and 30 ppm), water temperatures (3 and 20 ºC), leaf-to-water ratios (1:20 and 1:50), and flow rates (fast, medium, and slow). Performance of the chlorine wash was greatly affected by free chlorine level and wash water quality. Temperature, lettuce-to-water ratio, or water flow rate did not appear to have a significant impact. A prewash free chlorine concentration of 10 or 20 ppm was effective in preventing E. coli O157:H7 cross-contamination when lettuce was washed in tap water in the two washing systems assembled; 30 ppm of chlorine was needed to prevent cross-contamination during washing in industry water. Small-scale (100 ml) inactivation studies were performed to examine the impact of organic and solid contents (with the addition of lettuce juice and play sand) on the antimicrobial efficacy of chlorinated water. Increases in organic matter resulted in greater depletion of chlorine and the presence of solids enabled the pathogen to better survive chlorination; both led to a lower antimicrobial efficacy observed. ORP did not correlate linearly with free chlorine. E. coli O157:H7 cross-contamination was observed when ORP exceeded 650 mV, indicating that a threshold level of 650 mV may not ensure the safety of produce wash water. Since effective chlorine level is highly influenced by wash water quality, monitoring of produce washing systems may best be performed by measuring wash water quality in conjunction with rapid measurement of free chlorine.
Influence of temperature on the inactivation kinetics of Salmonella Enteritidis by the application of UV-C technology in soymilk Food Control (IF 3.667) Pub Date : 2018-06-29 Arícia Possas, Antonio Valero, Rosa Maria García-Gimeno, Fernando Pérez-Rodríguez, Poliana Mendes de Souza
The Ultraviolet-C technology is proposed as an alternative to thermal pasteurization for decontamination of soymilk, as heat treatments may adversely affect its quality. The aim of this study was to evaluate and model the influence of different processing temperatures (4-30 ºC) on the inactivation of Salmonella Enteritidis in soymilk at different UV-C doses. Inactivation efficiency was potentiated by the increase in temperature from 4 to 18 ºC. Higher temperatures (ranging from 18 to 30 ºC) did not yield significant differences between Salmonella maximum inactivation levels, i.e. difference between concentrations after and before treatments. The Weibull model was suitable to describe the inactivation data as a function of UV-C dose, at all temperatures evaluated. Since the Weibull shape parameter (p) was statistically homogeneous at temperatures ranging from 8-30 ºC (P > 0.05), it was fixed at its mean value (0.68 ± 0.08) and inactivation curves were re-fitted. Secondary modelling was conducted only to establish a relationship between Weibull model scale parameter (δ) and temperature. The δ estimations indicate that lower UV-C doses are required at 18-30 °C to attain a first tenfold reduction of Salmonella population in soymilk. Finally, a model combining primary and secondary models was developed to predict Salmonella inactivation at different UV-C doses and temperatures. This model provided acceptable predictions of inactivation data at temperatures within its limits. Accurate predictions of microbial inactivation curves at different combinations of UV-C doses and processing temperatures would be beneficial in setting favourable conditions of UV-C application to achieve desired levels of bacterial inactivation in soymilk.
Food Safety Knowledge, Attitudes and Practices of Food Handlers in Lebanese Hospitals: A cross-sectional study Food Control (IF 3.667) Pub Date : 2018-06-27 Christelle Bou Mitri, Darine Mahmoud, Najwa El Gerges, Maya Abou Jaoude
This study aims to assess the food safety knowledge, attitudes and practices among food handlers working in Lebanese hospitals and to explore the association between the obtained scores, handler socio-demographic and working characteristics.An observational cross-sectional study was carried out, using a semi-administered, semi-structured questionnaire interviewing 254 food handlers working in 13 different hospitals located in Beirut (n=7) and Mount Lebanon (n=6).The mean age of the 254 recruited food handlers was 37.6 ± 10.3 years, 63.8% were males, 60.1% had primary level education and the majority (90%) had previously received a course on food safety in hospitals. The most incorrect practice was thawing food at room temperature (72.8%). On average, food handlers scored 59.2%, 83.7% and 83.2% on the knowledge, attitudes and practices questions, respectively and 75.4% on the overall knowledge, attitude, practice (KAP) score. Knowledge scores were significantly higher among food handlers who attended a training course (60.8%, p = 0.001), working in government and hospitals not affiliated to university (71.3%, p = 0.013 and 60.5%, p = 0.013, respectively). Respondents who served for more than 21 years in university-affiliated hospitals were significantly (p < 0.001) more likely to have positive attitudes. The reported practices and overall KAP scores were significantly higher among those who had been working for more than 21 years, in government hospitals. Men scored better than women for practices scores (85.2%, 79.6%, p = 0.001).Resultsstrongly emphasize the need for continuous food safety interventions, training sessions and food hygiene regulations to enhance food handlers’ knowledge and improve food safety in hospitals.
Inner-filter effect based fluorescence-quenching immunochromotographic assay for sensitive detection of aflatoxin B1 in soybean sauce Food Control (IF 3.667) Pub Date : 2018-06-26 Hu Jiang, Wenjing Zhang, Juan Li, Lijuan Nie, Kesheng Wu, Hong Duan, Yonghua Xiong
A fluorescence-quenching immunochromotographic assay (ICA) was developed for sensitive detection of aflatoxin B1 (AFB1) in soybean sauce based on the inner filter effect (IFE) between flower-like gold nanoparticles (AuNFs) and quantum dots (QDs). QDs were sprayed on the test and control line zones as background fluorescence signals, whereas AuNFs were designed as the fluorescence absorber of QDs because the surface plasma resonance peak of AuNFs totally matched with the maximum emission peak of QDs. Under the optimal conditions, the fluorescence-quenching ICA strip showed a good linear detection for AFB1 in standard AFB1 solution from 0.008 μg/L to 1 μg/L with a low detection limit of 0.004 μg/L. The average recoveries for different concentrations of AFB1-spiked soybean sauce samples ranged from 84.69% to 120.44% with a coefficient of variation ranging from 2.73% to 10.41%. In addition, the reliability of the proposed method was further confirmed by ultra-performance liquid chromatography with fluorescence detection method. In brief, this novel IFE-based strip offers a simple, rapid, sensitive, and accurate strategy for quantitative detection of AFB1 in soybean sauce.
Comparative evaluation of impedanciometry combined with chromogenic agars or RNA hybridization and real-time PCR methods for the detection of L. monocytogenes in dry-cured ham Food Control (IF 3.667) Pub Date : 2018-06-26 Mirian Labrador, María Carmen Rota, Consuelo Pérez-Arquillué, Antonio Herrera, Susana Bayarri
Listeria monocytogenes is an important foodborne pathogen of particular relevance in “Ready To Eat” products. Food producers require rapid methods to detect L. monocytogenes, since the reference method (ISO 11290-1) is laborious, lengthy and costly. The aim of this study was to evaluate three alternative methods to detect L. monocytogenes in dry-cured ham following the ISO 16140-2:2016 standard: (A) impedance measurement followed by plating onto chromogenic agars; (B) impedance measurement followed by RNA hybridization, and (C) real-time PCR.Inclusivity and exclusivity were evaluated. The limits of detection 50 (LOD50) and the relative limits of detection (RLOD) were obtained by analysing dry-cured ham samples inoculated with L. monocytogenes at three different levels of contamination. The sensitivity study of alternative methods, as well as the relative specificity (SP), sensitivity (SE), and Kappa Cohen's index were calculated analysing 93 samples of sliced dry-cured ham. The inclusivity and exclusivity tests of three methods showed no interference in pathogen detection. LOD50 were very low for the three methods evaluated (<1 cfu/25 g dry-cured ham). The RLOD values of the three alternative methods were below the acceptability limit established by ISO 16140. For methods A and C, good results were obtained in the sensitivity study, as well as in the SP and SE. However, method B showed poorer results in the sensitivity study, along with lower results for SP (99.7%) and SE (79.6%), due to the occurrence of false positives and negatives in samples with presence of other Listeria spp.Methods A and C were considered to be a thoroughly appropriate control tool for use in the meat industry to improve the detection of L. monocytogenes.
Sublethal injury and recovery of Escherichia coli O157:H7 after ohmic heating Food Control (IF 3.667) Pub Date : 2018-06-21 Xiaojing Tian, Qianqian Yu, Lele Shao, Xingmin Li, Ruitong Dai
This study investigated the inactivation, sublethal injury, and recovery of Escherichia coli O157:H7 cells induced by ohmic heating (OH) in phosphate buffer saline (PBS) using thin agar layer (TAL) method. The voltage gradients of OH were 10 V/cm and 5 V/cm, which required 3 min and 13 min to reach the center temperature of 72 °C, respectively. The results indicated that OH at 10 V/cm voltage gradient had a comparable inactivation effect to 5 V/cm at the end of heating process. The proportion of sublethally injured cells in the survivors increased with increasing heating time and temperature and reached a maximum (> 97%) at the end of both treatments. When different liquid media, temperature, pH, and sodium chloride (NaCl) concentrations were used to study the recovery process of sublethally injured cells, limited nutrition, low temperature (4 °C), lower pH (4.0), and higher NaCl concentrations (more than 3%) significantly inhibited the recovery process. These results could provide the potential possibility to explore the combination of OH with other technologies (e.g. low temperature, low pH, and high salt) to inactivate targeted pathogens in foods.
Anticipation of food safety and fraud issues: ISAR - A new screening tool to monitor food prices and commodity flows Food Control (IF 3.667) Pub Date : 2018-06-21 K. Verhaelen, A. Bauer, F. Günther, B. Müller, M. Nist, B. Ülker Celik, C. Weidner, H. Küchenhoff, P. Wallner
Despite major efforts, food safety and food fraud issues continue to appear, showing the need for an improved risk anticipation to enhance consumer protection. To this end, we need a holistic view on the food production beyond the classical farm to fork principle and consider developments in- and outside the food chain. Commodity flows and prices are considered as relevant drivers for the emergence of food safety and fraud issues. To conveniently obtain information on these drivers and to monitor their changes, we developed a tool to analyze the volume, origin and price of foods imported to Germany, based on data of the German Foreign Trade Statistic. The ISAR-Tool (Import Screening for the Anticipation of Food Risks) facilitates a descriptive analysis of the import data of about 2400 different food items imported from 220 countries and an automated analysis of the data for a systematic detection of unexpected changes in import volumes and prices. For the automated approach, time series analyses using SARIMA and ETS models are applied and data points outside the model-based 99% prediction intervals are considered as potentially relevant changes. Monthly, more than 2000 of such changes are detected, leaving us with the challenging task of their evaluation for food safety and food fraud. To deal with the vast amount of results, of which the great majority cannot be linked to food safety or fraud issues, we implemented prioritization routines, and the 200 most critical results are considered for further expert evaluation. Despite remaining challenges in the performed evaluation process of the automated analysis, the described approach facilitates already at this stage an improved identification of food safety and food fraud hazards and the implementation of more targeted food safety controls, as shown in this paper. Our most prominent example of an identified food fraud and food safety risk was the detection of massive adulterations of hazelnut products with almonds and cashews, which were associated to the observed all-time high in hazelnut prices. Based on our findings, we conclude that the ISAR-Tool and the described analyses of commodity flows and prices can be important elements in the anticipation of risks and enable an enhanced consumer protection.
A novel hapten and monoclonal antibody-based indirect competitive ELISA for simultaneous analysis of alternariol and alternariol monomethyl ether in wheat Food Control (IF 3.667) Pub Date : 2018-06-21 Jianyi Wang, Tao Peng, Xiya Zhang, Kai Yao, Yuebin Ke, Bing Shao, Zhanhui Wang, Jianzhong Shen, Haiyang Jiang
This study synthesized a new alternariol (AOH) hapten. The AOH had an alkylation reaction with ethyl 4-bromobutyrate, followed by hydrolysis and purification, and then conjugated with keyhole limpet hemocyanin to immunize mice and successfully produced two kinds of monoclonal antibodies (mAbs), namely the antibodies which can recognize both AOH and alternariol monomethyl ether (AME) and the ones that can specifically recognize AOH. Wherein, mAb 13D8 can uniformly recognize AOH and AME with the 50% inhibition concentration (IC50) values of 9.4 ng/mL and 9.7 ng/mL, respectively. An indirect competitive ELISA (icELISA) was established by mAb 13D8 to simultaneously detect AOH and AME, with the limit of detection (LOD) being 0.7 ng/mL and 1.0 ng/mL, respectively. The average recoveries in spiked wheat sample were 84.5–107.6% with the coefficient of variation (CV) lower than 10%. The established icELISA method was used to detect 13 real samples with the same results as HPLC-MS/MS, indicating that the method is suitable for simultaneous detection of AOH and AME in wheat.
Study of fish products in Metro Vancouver using DNA barcoding methods reveals fraudulent labeling Food Control (IF 3.667) Pub Date : 2018-06-18 Yaxi Hu, Shr Yun Huang, Robert Hanner, Julia Levin, Xiaonan Lu
The complexity of seafood supply chains and fish naming systems has rendered the traceability of a seafood product challenging if not impossible, creating loopholes for intentional or unintentional illicit practices that erode the market transparency and integrity. DNA barcoding has been extensively applied to evaluate the integrity of seafood markets worldwide. However, little information is available to comprehensively assess the fish market integrity in Metro Vancouver, the 3rd largest metropolitan city in Canada. Therefore, we conducted a market survey by collecting 285 finfish samples from grocery stores, sushi bars and non-sushi restaurants in Metro Vancouver and used DNA barcoding and DNA mini-barcoding to analyze the compliance of product market names with allowable species in accordance with the Canadian Fish List. On average 25% of the samples were mislabeled. Restaurants had the highest mislabeling rate (i.e. 29%), followed by grocery stores (i.e. 24%), while sushi venues (i.e. 23%) had the least mislabeling incidence. Among the mislabeled products, snappers presented the highest mislabeling rate (i.e. 91%). Evidence of the various motivations of the mislabeling, including intentional substitution using less expensive species, purposed mislabeling of by-catch or illegal, unreported and unregulated fishing products, and unintentional misidentification or misuse of dialects and vernaculars were all observed. To protect the integrity of the seafood supply chain, several recommendations on the labeling standards are discussed: harmonize the accepted common names with major trading countries; enforce labels to include scientific names for fish products; disapprove the use of vague multispecies generic names; and require labels to provide information of geographical origins and catching/farming methods. These actions have contributed to the significant improvement of seafood market integrity in the European Union and are anticipated to be effective in Canada.
Investigating the current skim milk powder inspection strategies for improvements in process optimisation. Food Control (IF 3.667) Pub Date : 2018-06-18 Niamh Burke, Mark Southern, Alan Ryan, Catherine C. Adley
The production of skim milk powder (SMP) has increased among Irish Dairy processors in recent years. SMP has nutritional benefits and functional properties, including high calcium and potassium, a low fat content, excellent gelation, emulsification and foaming properties. As Irish dairy exports are increasing year on year, the requirement to intensify process optimisation is heightened. This study investigated the analytical test levels applicable to the regulatory requirements for the quality and safety assurance in the production of SMP across a 12 month period in two large Irish milk processing plants. The efficacy of the testing strategies and turnaround time for SMP for both plants were examined and compared. The results of this study demonstrate excess testing at 64% and 36% respectively, over the regulatory requirements for both companies. The sediment and density tests demonstrated the highest out of specification excess test results for each plant respectively. This is the first study to our knowledge on optimising sampling regimes in a dairy processing setting and the outcomes of this study propose an overview to the current SMP testing strategies for improvement in process optimisation for any milk product, focusing on the process in order to optimise overall production levels and to address analytical test levels, out of specification results and laboratory turn-around time (TAT).
Stringent sampling inspection plans using upper envelopes for cell counts Food Control (IF 3.667) Pub Date : 2018-06-14 K. Govindaraju, M. Bebbington, R. Kissling
A new type of stringent sampling inspection plan is proposed for cell counts generally in line with a Poisson or a mixed-Poisson type of distribution. The proposed plan is based on setting an upper envelope estimated from the sample counts which should remain below the given microbiological limit m. We used Monte-Carlo simulation methodology to evaluate the proposed plans and showed that the lot acceptance criterion using the upper envelope improves consumer protection in general. Both two and three class attribute plans are investigated for establishing the upper envelope. Our study reveals that the proposed plans can offer better consumer protection and economy when compared to both two and three class attribute plans. It is also demonstrated that a slightly stringent plan can be found in place of lognormal type variables plans. The limitations of the proposed new plans, and a discussion on alternative stringent rules for batch acceptance are also provided. The new plan was also validated using the APC cell counts observed for 2000 milk powder batches. Our conclusion is that the proposed stringent plans can improve protection to the consumer, particularly for exported food products.
Effect of Display Case Cooling Technologies on Shelf-Life of Beef and Chicken Food Control (IF 3.667) Pub Date : 2018-06-14 Keith Vorst, Niraja Shivalingaiah, Ana Lorena Monge Brenes, Shannon Coleman, Aubrey Mendonça, J. Wyatt Brown, Angela Shaw
Shelf-life is defined as the time a food product retains its desired sensory, chemical, and physical characteristics while also remaining safe for consumption. Bacteria associated with meat spoilage produce off-odors and flavors, tissue discoloration, gas, and slime. The objectives of this study were, 1) to determine the effect of refrigerated-display-case type on the shelf-life and microbial load of the natural flora found on beef steak and chicken breasts and, 2) to evaluate the effect of gravity coil conductive cooling vs. complete conductive cooling on the growth of Escherichia coli K12 artificially inoculated onto beef steak under abusive conditions. In Study 1, beef steak and chicken breasts were placed for 8 or 5 days, respectively, in a conduction cooling gravity assist service case, gravity coil service case with partial conduction coil base deck, gravity coil service case with serpentine assist, or blower coil service case with an additional fogging system. Mesophilic bacteria, Pseudomonas spp. and psychrotrophic bacterial counts on meat surfaces, and meat color, internal meat temperature, case temperature and case relative humidity were determined daily. In Study 2, two of the four types of display case ̶ the complete conductive cooling and gravity-coil conduction cooling systems ̶ were chosen to evaluate microbial growth on beef steak due to novel conductive cooling technologies. Temperature and weight loss, aerobic plate counts and viable E. coli colony-forming-units on the beef steaks were determined daily. In study 1, the warmest display ambient air temperature was found in the gravity coil service case with partial conduction coil base deck (PCC). The coldest tissue temperatures were observed for steaks and chicken breasts placed in the conduction cooling gravity assist service display case. The lowest RH also tended to occur in the PCC case. Overall, the type of retail display case had no effect on the growth of mesophilic and psychrotrophic bacteria or Pseudomonas on both steaks and chicken breasts. In study 2, the initial numbers of viable E. coli K12 on inoculated steaks were low and remained low through 7 days storage, regardless of display case. The novel conduction cooling gravity assist service display case used in this study has the greatest potential for extending shelf-life due to lower overall tissue temperatures and reduced water loss from meat products held in this case during high traffic and abusive retail conditions.
How consumer confidence in food safety practices along the food supply chain determines food handling practices: Evidence from Ghana Food Control (IF 3.667) Pub Date : 2018-06-14 Carl Johan Lagerkvist, Franklin Amuakwa-Mensah, Justice Tei Mensah
The relationship between consumer confidence in food safety measures for vegetables sold in open markets and their use of safe food handling practices in the domestic environment was investigated for a set of 332 randomly sampled vegetable consumers within the suburbs of Accra, Ghana. More specifically, the confidence of consumers in twelve food safety measures employed by farmers, middlemen and traders was assessed, together with the frequency of treatment of vegetables with salt or vinegar and whether or not vegetables were stored in a hygienic and ventilated place. The results suggest that the level of consumer confidence in food safety measures along the value chain of vegetable production influences their food safety actions. Principal component analysis identified two factors determining confidence: (a) cleanliness and contact exposure, and (b) safe practices related to water, pesticides and fertilisers in production and general hygiene at the selling point. Structural equation modelling showed that confidence was significantly related to the cleanliness and contact exposure component (path coefficient = 0.41, p=0.002), but only indirectly to the safe production practices and hygiene component (r=0.71). Moreover, confidence then directed storage (path coefficient = 0.54, p<0.001), but impaired use of salt or vinegar (path coefficient = -0.29, p=0.0015). Furthermore, multinomial logit modelling revealed a significant association between delayed vegetable consumption and frequency of treatment of vegetables with salt or vinegar before cooking or eating (χ2=13.2, p<0.05). It also showed that the marginal effects of changes in the two principal components of confidence operated differently for groups of consumers who differed in their combined use of storage and treatment. These findings have implications for food risk communication and actions to improve local conditions under which food is sold.
Heat resistance of Salmonella Enteritidis in four different liquid egg products and the performance and equivalent conditions of Ministry of Food and Drug Safety of South Korea and US Department of Agriculture protocols Food Control (IF 3.667) Pub Date : 2018-06-14 Il-Byeong Kang, Dong-Hyeon Kim, Dana Jeong, Jin-Hyeong Park, Hyun-Woo Lim, Kun-Ho Seo
Heat treatment is one of the most effective methods for eliminating undesirable microorganisms from foods. Salmonella Enteritidis has long been known to be strongly associated with liquid egg products. To investigate the influence of the liquid egg matrix on the heat tolerance of residual bacteria, we evaluated the thermal inactivation D-values of S. Enteritidis in four different liquid egg products (egg white, whole egg, egg yolk, and egg yolk plus 10% NaCl). Additionally, the performance and science-based equivalent conditions of the Ministry of Food and Drug Safety (MFDS) and US Department of Agriculture (USDA) protocols for liquid egg products were investigated using calculated D-values. Liquid egg products inoculated with S. Enteritidis were heated in capillary tubes to temperatures ranging from 51 to 59°C and then spread onto tryptic soy agar plates, followed by incubation at 37°C for 24 h. S. Enteritidis showed the lowest D-values in egg whites, followed by whole eggs and egg yolks. The addition of NaCl to egg yolks increased the heat resistance of S. Enteritidis. MFDS protocols for egg whites and whole eggs showed higher performance, whereas MFDS protocols for egg yolks and egg yolks plus 10% NaCl showed lower performance than USDA protocols. Overall, our findings may facilitate greater flexibility in egg pasteurization.
Colorimetric determination of alcohols in spirit drinks using a reversible solid sensor Food Control (IF 3.667) Pub Date : 2018-06-14 N. Jornet-Martínez, R. Gómez-Ojea, O. Tomás-Huercio, R. Herráez-Hernández, P. Campíns-Falcó
A sensor for the colorimetric estimation of the alcoholic content has been developed based on the entrapment of the reagent (4-N,N-dioctylamino)-4‘-trifluoroacetylazobenzene (ETHT 4001) into polydimethylsiloxane (PDMS) modified with tretraethylorthosilicate (TEOS). When exposed to an alcoholic media, the sensor delivers ETHT 4001 so that it reacts with alcohols, resulting in a change in the solution color. The diffusion of the entrapped ETHT 4001 from the polymeric sensor to the working solution depends on the hydrophobicity of both the sensor matrix and the media, while the time of exposure determines whether the reagent reacts with methanol, or with methanol and ethanol. Thus, the sensors are a versatile tool for the estimation of the methanol content in ethanol or in ethanol/water mixtures, and for the measurement of the total alcoholic content (methanol plus ethanol) in an hydroalcoholic media. The proposed sensors are very easy to prepare, and show good precision and long-term stability. Moreover, the reagent delivery is reversible which allows its recovery once the absorbance measurements have been made simply by adding water, so the sensors can be reutilized and the generation of wastes is reduced. The potential utility of the proposed sensors has been demonstrated by measuring the alcoholic strength of commercial spirit drinks, and the methanol content in spiked hydroalcoholic samples.
Effect of different baking treatments on the acrylamide formation and phenolic compounds in Californian-style black olives Food Control (IF 3.667) Pub Date : 2018-06-13 Francisco Pérez-Nevado, Manuel Cabrera-Bañegil, Elena Repilado, Sara Martillanes, Daniel Martín-Vertedor
The acrylamide content in oxidised black olives and the influence of baking treatments on the concentrations of acrylamide and phenolic compounds were determined. Twenty different randomly selected commercial brands of olives were purchased from industries located in Spain and Portugal, for analysis of the acrylamide contents. A wide variation in acrylamide concentration was obtained for the commercial canned black ripe olives and brine. Various baking temperatures and times were applied to the table olives with the lowest acrylamide content. The baking treatments significantly increased the acrylamide amount in olives and drastically reduced the phenolic compounds. The phenolic compounds had a strong negative linear correlation with the acrylamide content.
Dynamic Analysis Of Competitive Growth Of Escherichia Coli O157:H7 In Raw Ground Beef &z.star; Food Control (IF 3.667) Pub Date : 2018-06-12 Cheng-An Hwang, Lihan Huang
The objective of this study was to investigate the growth of Escherichia coli O157:H7 in raw ground beef under competition from background flora. The growth of E. coli O157:H7 was observed in sterile irradiated and non-irradiated raw ground beef under dynamically changing temperature conditions. A one-step dynamic analysis method was used to directly construct tertiary models for describing bacterial growth with and without competition and to estimate the kinetic parameters from dynamic growth curves to prove the hypothesis that the growth of E. coli O157:H7 was significantly affected by competition from background flora in raw ground beef.
Thermal Inactivation of Fungi in Chestnuts by Hot Air Assisted Radio Frequency Treatments Food Control (IF 3.667) Pub Date : 2018-06-11 Lixia Hou, Xiaoxi Kou, Rui Li, Shaojin Wang
Infestations with fungi in chestnuts are one of the major safety issues during process and storage, resulting in short shelf-life and high economic losses. The purpose of this research was to study possible applications of radio frequency (RF) treatments for pasteurization of chestnuts to replace chemical methods. Thermal lethal kinetic models of fungi isolated from spoilage chestnuts and parameters of the developed model were determined. A 6 kW, 27 MHz free-running oscillator RF system combined with hot air heating was used to validate the treatment parameters based on thermal lethal kinetic models of fungi. The results showed that four mycotoxigenic fungi dominated and were isolated at frequency of 58.31±2.39% for Penicillium crustosum, 17.78±5.00% for Penicilluim discolor, 15.66±7.67% for Penicillium expansum, and 14.24±6.71% for Penicillium glabrum from a total sample size of one hundred spoilage nuts. Modified Weibull distribution model (R2=0.939 to 0.999) had a better description of the inactivation behavior of Penicillium sp. than the first-order kinetic model (R2=0.829 to 0.993) and P. crustosum was the most heat resistant fungi in chestnuts. Heating chestnuts to 60 °C or higher using hot air assisted RF energy resulted in 4-log reductions of P. crustosum isolated from moldy chestnuts. Quality of chestnuts was not influenced by the hot air assisted RF treatments because no significant differences in moisture, firmness, and color were observed between thermal treatments and untreated controls. Meanwhile, RF treatments also help to inhibit the growth of fungi during accelerated shelf life storage. The RF treatments may provide a rapid and environmentally friendly method to replace chemical fungicide for pasteurizing chestnuts.
NGS-based amplicon sequencing approach; towards a new era in GMO screening and detection Food Control (IF 3.667) Pub Date : 2018-06-08 Alfred J. Arulandhu, Jeroen van Dijk, Martijn Staats, Rico Hagelaar, Marleen Voorhuijzen, Bonnie Molenaar, Richard van Hoof, Rong Li, Litao Yang, Jianxin Shi, Ingrid Scholtens, Esther Kok
The development and commercialization of Genetically Modified Organisms (GMOs) and its related products have been increasing in the last two decades. This challenges the currently applied time-consuming and expensive qPCR screening procedure from a practical perspective, due to the necessity to develop and validate additional targets at a regular pace and the increasing number of targets included in a single screening. In this study we developed a next generation sequencing (NGS)-based GMO screening approach covering 96 GMO targets and compared it to the two-step qPCR GMO screening approach; the two approaches were evaluated with five feed samples known to contain GMOs. The amplicons obtained from the feed samples were analyzed using 150-bp Paired-End sequencing, Illumina HiSeq 4000 platform. A dedicated data analysis pipeline was developed, which allows automated identification of GMOs and associated genetic elements and constructs. The result of the NGS-based screening were compared with the qPCR approach, indicating that 92% of the targets were commonly identified between the qPCR and NGS-based screening. The remaining 8% of the targets had discrepancies in detection between the two methods. This was mainly observed for targets that were detected in qPCR with high Cq values (above 36), which could not be detected in NGS-based screening. Additionally, due to the more extensive screening in the NGS-based strategy, in total 43 additional GMOs and related targets were identified compared to the standard qPCR screening. From the commonly identified targets in both approaches, 8 targets could not be associated with the detected GMOs. These targets had late Cq values (above 36) and could indicate traces of unknown GMOs in the samples. The current study shows the applicability of NGS as a novel, broad and reliable screening strategy for GMOs and its potential to improve current screening methods.
A review on the application of chromatographic methods, coupled to chemometrics, for food authentication (Chromatography-chemometrics in food authentication) Food Control (IF 3.667) Pub Date : 2018-06-08 M. Esteki, J. Simal-Gandara, Z. Shahsavari, S. Zandbaaf, E. Dashtaki, Yvan Vander Heyden
The increase of food adulteration, inducing losing a large amount of money as well as of the confidence of consumers, has become an urgent issue for producers, researchers, governments and consumers. Chromatographic methods, in combination with chemometrics, are usually developed and applied throughout the food chain to verify the nature or origin of food, with both targeted (metabolomics) and non-targeted (profiling) approaches. Their operation, together with their advantages and drawbacks, will be discussed in this review to show strategies to solve food authentication issues.
Identification of single target taxon-specific reference assays for the most commonly genetically transformed crops using digital droplet PCR Food Control (IF 3.667) Pub Date : 2018-06-07 Jacchia Sara, Kagkli Dafni-Maria, Lievens Antoon, Angers-Loustau Alexandre, Savini Christian, Emons Hendrik, Mazzara Marco
Knowledge of the number of DNA sequences targeted by the taxon-specific reference assays is essential for correct GM quantification and is key to the harmonisation of measurement results. In the present study droplet digital PCR (ddPCR) was used to determine the number of DNA target copies of taxon-specific assays validated for real-time PCR for the four main genetically modified (GM) crops. The transferability of experimental conditions from real-time PCR to ddPCR was also explored, as well as the effect of DNA digestion. The results of this study indicate that for each crop at least one taxon-specific assay can be identified as having a single DNA target. A short list of taxon-specific reference assays is proposed as best candidates for the relative quantification of GM events for soybean, maize, cotton and oilseed rape. The investigated assays could be in most cases transferred to ddPCR without further optimisation. The use of DNA digestion did not improve ddPCR characteristics such as rain and resolution at the conditions tested.
Food allergies and perceptions towards food allergen labelling in Mauritius Food Control (IF 3.667) Pub Date : 2018-06-07 Soogali Nabiilah Bibi, Jan Mei Soon
There remains a paucity of research in food allergies in Sub-saharan Africa. It is the aim of this study to determine the self-reported prevalence of food allergies and consumers’ perceptions towards food allergen labelling in Mauritius. A survey was conducted in four supermarkets in the Municipalities of Vacoas-Phoenix, Quatre-Bornes and Moka during the period of September to November 2017. The questionnaire was designed based on previous studies and administered using a face-to-face interview approach to increase completion rate. Descriptive analysis and one-way ANOVA between subjects design were conducted. Shellfish was reported as the most common causative agent followed by fish, egg and peanut. Respondents were satisfied with the current font size and general information provided in food labels. Respondents agreed that it could be problematic to identify suitable foods for individuals suffering from food allergies or intolerances. Variations of PAL statements and generic terms provided in food labels, and location of allergy warnings were cause for concern. More than 80% of the respondents felt that allergens in ingredient list should be emphasised (e.g. bold font) and plain English or French language should be used to describe allergenic ingredients. The findings in this study provide practical insights on food allergen labelling issues for policy makers and stakeholders in the food supply chain. Determining the prevalence of food allergies in the country will inform policy makers to consider adding shellfish and other major allergenic ingredients to the list of ingredients requiring mandatory allergen warning label in Mauritius.
The quality and safety of food contact materials – paper and cardboard coated with paraffin emulsion Food Control (IF 3.667) Pub Date : 2018-06-05 M. Nowacka, K. Rybak, A. Wiktor, A. Mika, P. Boruszewski, J. Woch, K. Przybysz, D. Witrowa-Rajchert
The aim of this study was to assess the quality of paper and cardboard coated with different emulsions as food contact materials. The paper and cardboard were covered (impregnated) with a single layer of three different emulsions produced using paraffin and waxes, varying in content of dry matter, pH and emulsifiers. The organoleptic properties, overall and specific migration expressed as cadmium and lead content, were evaluated. Moreover, the water and oil contact angle and samples’ microstructure were analyzed in order to determine the resistance of materials to moisture and grease penetration. The analysis of scanning electron microscope (SEM) images indicated that some of the examined emulsions penetrated the material, and others created a layer of coating. Impregnation of paper and board caused a change in smell, but did not influence the taste of food used to test the impact on sensorial properties. It is worth emphasizing that overall migration limit was not exceeded in the case of all investigated samples. The samples impregnated with emulsion were characterized as having better water (including water vapor) and oil in comparison with the non-coated ones.
Occurrence of aflatoxins B1 and M1 in milk powder and UHT consumed in the city of Assomada (Cape Verde Islands) and southern Brazil Food Control (IF 3.667) Pub Date : 2018-06-05 Keven David Moreira Gonçalves, Karen Vanessa Marimón Sibaja, Ana Carla Penteado Feltrin, Rafael Diaz Remedi, Sabrina de Oliveira Garcia, Jaqueline Garda-Buffon
The occurrence of aflatoxins M1 (AFLAM1) and B1 (AFLAB1) was evaluated in 112 milk samples (whole, skimmed, semi-skimmed—liquids and powders), collected at a local commercial establishment in southern Brazil and Assomada City, Cape Verde. AFLAM1 and AFLAB1 were determined by using high-performance liquid chromatography with fluorescence detection. For the 62 milk samples from 41 supermarkets in the city of Rio Grande, Rio Grande do Sul, 68% were contaminated by AFLAM1 (range, 40–3670 ng L-1) and 16% were contaminated by AFLAB1 (range, 40–600 ng L-1), with contamination found only in liquid milk. Among the 50 samples from Assomada City, AFLAM1 was detected in 76% of the samples (range, 32–2896 ng L-1), at values below the current Brazilian legislation for the maximum permitted level in milk powder (5000 ng L-1) but higher than that recommended by the European Commission.
Long-term antibacterial efficacy of disinfectants based on benzalkonium chloride and sodium hypochlorite tested on surfaces against resistant gram-positive bacteria Food Control (IF 3.667) Pub Date : 2018-06-05 Abel G. Ríos-Castillo, Fabio Fontecha Umaña, José J. Rodríguez-Jerez
The long-term antibacterial activity of disinfectant products based on benzalkonium chloride and sodium hypochlorite on surfaces was evaluated for prevention of bacterial adhesion. To this end, the European standard EN 13697, which determines the antibacterial activity of disinfectant formulations on bacteria, was adapted. As a prior step, the initial antibacterial activity (≥4 log10) was determined and after 24 h the long-term efficacy (≥3 log10) of each disinfectant product. Gram-positive bacteria belonging to the genera Staphylococci and Enterococci are able to survive in adverse conditions and have been involved in the increasing of bacterial resistance to different antimicrobials. In this study, Staphylococcus aureus and Enterococcus hirae were selected as ‘indicator organisms’ for the presence of bacterial contamination. The results showed that all the disinfectant products based on benzalkonium chloride and sodium hypochlorite had an initial antibacterial activity of up to 4 log10. After 24 h, the benzalkonium chloride based products demonstrated long-term antibacterial efficacy for both bacterial strains. Sodium hypochlorite as a sole compound at 4.0% did not demonstrate long-term efficacy, but when it was formulated with sodium hydroxide, benzalkonium chloride, fatty alcohol ethoxylate and amine oxide, it was effective. The bactericidal test developed in this study fulfills the purpose of evaluating the long-term antibacterial efficacy of disinfectant products on surfaces.
A meta-analysis on the effectiveness of electrolyzed water treatments in reducing foodborne pathogens on different foods Food Control (IF 3.667) Pub Date : 2018-06-05 George Kwabena Afari, Yen-Con Hung
The aim of this meta-analysis was to develop an overall estimate of the pathogen reductions achieved when food products are treated with electrolyzed (EO) water. A literature search and systematic review was conducted to identify EO water intervention studies to reduce Escherichia coli O157:H7, Salmonella and Listeria monocytogenes on poultry, eggs, meat, fish and produce. Pathogen reduction data from the included studies were utilized in the estimation of effect sizes (mean log reductions) and heterogeneity assessment between studies (I2). Twenty-seven studies (294 observations) were obtained and the sanitizers identified as controls were water and sodium hypochlorite. Summary effects of 0.66, 1.12, 1.15, 2.41, 4.45 and 5.34 log reductions were estimated for EO water treatments on poultry, fish, meats, lettuce, eggs and tomatoes, respectively. Highest reductions were estimated for smooth-surfaced foods (eggs, tomatoes) while pathogen reductions were lower on muscle foods. I2 ranged between 60-99%, indicating high heterogeneity and necessitating the use of meta-regressions to assess the variations. Free chlorine concentration (FCC), time and temperature were significant variables (p<0.05) in estimating EO water effectiveness, although no single variable was significant for all the products. The developed meta-regression models were applied to a selected treatment condition (30 mg/L FCC, 20 o C, 3 min) to attain 2.09, 5.27, 0.87 and 4.91 predicted log reductions on lettuce, tomatoes, meats and eggs, respectively. This analysis provides a precise estimate of the inactivation effect of EO water on different foods that can be applied in quantitative risk assessments for ensuring food safety.
Multiple-locus variable-number tandem repeat analysis using multiplex polymerase chain reaction and next-generation sequencing - a novel high-throughput method for subtyping Listeria strains Food Control (IF 3.667) Pub Date : 2018-06-05 Chirapiphat Phraephaisarn, Yurika Kitai, Rabuesak Khumthong, Hajime Takahashi, Chihiro Ohshima, Punnida Techaruvichit, Mongkol Vesaratchavest, Rutjawate Taharnklaew, Suwimon Keeratipibul
Listeria monocytogenes is significantly associated with listeriosis infection. Several species of Listeria other than L. monocytogenes directly affect the food industry. In the present study we developed a novel subtyping method for tracking the source of L. monocytogenes and L. innocua in large-scale investigations using multiple-locus variable-number tandem repeat analysis (MLVA) coupled with next-generation sequencing (NGS). Forty-eight L. monocytogenes and L. innocua strains isolated from a food processing plant and the environment were used for the amplification of 15 specific variable number tandem repeat (VNTR) loci. The results exhibited 100% concordance for amplicon detection using both the subtyping methods. Coupling of MLVA with capillary electrophoresis (CE) or NGS detected 38 and 89 different alleles, respectively. MLVA coupled with NGS showed significantly higher discriminating power than MLVA coupled with CE. In MLVA coupled with NGS method, locus JLR1 of L. monocytogenes had 54% discrimination while locus TR3 had 100% discrimination solely in L. innocua. In addition, MLVA coupled with NGS method had significantly higher discrimination power (DI=1.0 with 48 MLVA patterns) than that of MLVA coupled with CE (DI=0.79 with 15 MLVA patterns). These results indicate the advantage of MLVA coupled with NGS method in detecting not only the length but also sequence polymorphism in a single read run. MLVA coupled with NGS led to significant reduction in labor and cost than CE and the traditional Sanger sequencing. Thus, MLVA coupled with NGS is an effective and feasible technique for the molecular typing of Listeria species in food industries.
Challenges and difficulties in the implementation of a food safety management system in Thailand: A survey of BRC certified food productions Food Control (IF 3.667) Pub Date : 2018-06-04 Prachara Chaoniruthisai, Prattana Punnakitikashem, Kittichai Rajchamaha
There have been a series of contaminated food crises over the world in recent decades. FSMSs have been used by food producers to ensure food safety. However, there are various challenges and difficulties that exist which impede the effective implementation of FSMS. This paper aims to 1) identify and prioritize those challenges and difficulties in an effort to more effectively implement FSMS by Thai BRC certified production, 2) indicate the contextual factors of food organization (i.e. firm size and QA systems) and investigate their impact on the effectiveness of BRC implementation, and 3) examine whether the Food Safety Team (FST) number could moderate the association between firm size and effectiveness. To achieve the objectives and answer the questions, a quantitative methodology approach was used to develop a survey to gather data from 217 food safety and quality managers throughout the country. Descriptive and inferential statistics were used to analyze the data. The results showed that sampling was dominated by larger-sized firms (67.1%), meaning firms employed in excess of 200 people. By exploratory factor analysis, four difficulty constructs were extracted and named in descending order of mean value as organizational and staff capacity, finance and budgeting, human characteristics, and system requirements. The study of contextual factors showed a significant outcome in firms with BRC-certified production together with the complement of ISO 9001 and HACCP systems, i.e., these firms were considered to be more effective. However, there was no significant effect due to interaction by FST number on the relationship of firm size and effectiveness.
The effect of photosensitization mediated by curcumin on storage life of fresh date (Phoenix dactylifera L.) fruit Food Control (IF 3.667) Pub Date : 2018-06-04 Fahad Al-Asmari, Ram Mereddy, Yasmina Sultanbawa
The effect of photosensitization mediated by curcumin (CUR) in sanitizing the fresh date fruit surface was investigated. Approximately 3 – 4 µl CUR solution ranging from 1000 to 1800 µM was sprayed on the date surface, followed by irradiation using blue light at 420 nm for 10 and 15 min at light dosages of 180 J/cm2 and 270 J/cm2 respectively. After irradiation, the date was stored at 4˚C and 30˚C until fungi was visually observed. The combination of CUR and light resulted in significant (p<0.05) extension of the shelf life and quality of fresh date. The shelf life of date fruit photosensitized by 1400 µM CUR for 10 min and stored at 30˚C lasted for 14 days in comparison to the 7 days for the control, while date stored at 4˚C lasted 98 days for the photosensitized fruit compared to the control of 28 days under the same conditions. In addition, no changes in physico-chemical characteristics were observed after treatment. The sanitization treatment of photosensitization mediated by CUR indicated a promising strategy in extending the shelf life of fresh date fruit. Clean and green technologies that are environmentally friendly like photosensitization are preferred by consumers to the synthetic chemicals used in conventional practices for sanitizing food.
Italian tomato-based products authentication by multi-element approach: a mineral elements database to distinguish the domestic provenance Food Control (IF 3.667) Pub Date : 2018-06-04 Rosaria Fragni, Antonio Trifirò, Ada Nucci, Andrea Seno, Alessia Allodi, Matteo Di Rocco
In this study, we propose a novel mineral elements database for the authentication of Italian processed tomato, able to discriminate the domestic provenance from the Chinese, US and Spanish ones.Multi-element analyses by Inductively Coupled Plasma orthogonal acceleration Time-of-Flight Mass Spectrometry (ICP-oa-TOF-MS) and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) were used for quantifying 26 mineral elements (Li, Be, Na, Mg, Al, K, Ca, V, Cr, Mn, Co, Cu, Zn, Ga, As, Rb, Sr, Ag, Cd, In, Cs, Ba, Tl, Pb, Bi and U) in 183 tomato-based samples of different origin (Italy, China, US and Spain) collected in three different years of production (2013, 2015 and 2017). Linear Discriminant Analysis (LDA) applied to 28 variables (single elements + elemental ratios) allowed excellent separation between Italian and non-Italian tomato samples. Three elemental ratios (Li/Cu, Co/Rb and Sr/Cd) resulted highly effective in identifying the domestic provenance of tomato (100% prediction ability of the model and 98.8% in cross-validation). This result highlighted that ratios between elements were more important than single elements in discrimination.
Growth and toxin production of Bacillus cereus strains in reconstituted initial infant milk formula Food Control (IF 3.667) Pub Date : 2017-05-06 Šárka Bursová, Lenka Necidová, Danka Haruštiaková
Bacillus cereus may cause two different types of foodborne illness: diarrheal and emetic syndromes. Dried infant formulae are at risk of contamination by the B. cereus, which is reflected by the requirement for the microbiological examination of foods listed in Regulation (EC) 2073/2005, as amended. This study evaluates the growth and toxin production potential of B. cereus in reconstituted dried infant milk formula. Powdered milk was inoculated with approximately 1 log and 3 log cfu g−1 of spore suspension of toxigenic B. cereus strains and then stored as reconstituted milk for 48 h at 8 °C, 15 °C, and 24 °C. The growth of B. cereus, tested by the plate method, and production of the emetic toxin and enterotoxins, tested by the gold-labelled immunosorbent assay, were regularly detected during 48 h of storage. The Baranyi-Roberts model was used to study the growth potential of B. cereus strains. In reconstituted infant milk, B. cereus did not grow at 8 °C during 48 h of storage. B. cereus multiplied and formed toxins only at 15 °C and 24 °C. The growth curve of the bacteria stored at 15 °C included the lag and exponential phases, and the growth was not completed during the period. The growth of B. cereus at 24 °C was completed, peaking within 27 and 20 h, with the low and high inoculum sizes, respectively. Detectable amounts of toxins were formed during the bacterial growth of around 5 log cfu ml−1 (non-hemolytic enterotoxin) and 7 log cfu ml−1 (hemolysin BL and emetic toxin). Model experiments evaluated consumer risk from B. cereus toxins resulting from extended storage of reconstituted infant milk formula at improper temperatures.
Effect of Tea Marinades on the formation of polycyclic aromatic hydrocarbons in charcoal-grilled chicken wings Food Control (IF 3.667) Pub Date : 2017-12-07 Chong Wang, Yunting Xie, Jun Qi, Ying Yu, Yun Bai, Chen Dai, Chunbao Li, Xinglian Xu, Guanghong Zhou
Aflatoxin degradation by Bacillus subtilis UTB1 is based on production of an oxidoreductase involved in bacilysin biosynthesis Food Control (IF 3.667) Pub Date : 2018-03-01 Hamideh Afsharmanesh, Alejandro Perez-Garcia, Houda Zeriouh, Masoud Ahmadzadeh, Diego Romero
Aflatoxins produced by some strains of the fungal genus Aspergillus are among the most hazardous mycotoxins for humans and livestock, a reason that has forced to investigate efficient strategies of management of these fungal contaminations. Some bacterial species have been proven capable of degrading or modifying aflatoxin into less- or nontoxic derivatives. In a previous work, Bacillus subtilis UTB1 was already proposed as a good candidate to be used for degradation of aflatoxin. Aiming to deepen in this biological activity, in this study, we searched for homologous to enzymes of Mycobacterium smegmatis degrading aflatoxin within the genus Bacillus. A candidate was the gene bacC, an oxidoreductase enzyme dedicated to the production of the antimicrobial di-peptide bacilysin. bacC mutants were compromised in the inhibitory activity against A. flavus, and the degradation of aflatoxin, compared to wild type both in vitro and on pistachio fruits. Taken together, our findings led us to propose a double and complementary mechanism by which BacC contributes to the reduction of aflatoxin levels in pistachio fruits: first, by a direct antagonism towards A. flavus, presumably mediated by the peptide bacilysin, and second, by a degradative or modifying activity of aflatoxin.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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