Microbial safety of oily, low water activity food products: A review
Section snippets
Fatty or oily, low water activity (OL aw) foods
Foods with low water activity (aw) (<0.70) have a long shelf life and can be shelf stable for years. The number of food items and food ingredients considered to be or that can contribute to the low aw of a food are almost limitless. Examples of products in this category include soup mixes, spices, herbs, nuts, dried fruits and vegetables, dried meats, chocolate, cocoa, pasta, breakfast cereals, cake mixes, powdered milk and infant formula, egg powder, hydrolyzed vegetable protein, snacks,
Manufacture of tahini and halva
Tahini and halva-making technologies are based on traditional methods and have been described in the literature in detail (QUALEB, 2015; Mureşan et al., 2013). The technological features of tahini and halva manufacture are presented schematically in Fig. 1, Fig. 2, respectively.
Tahini is mainly manufactured by milling roasted and dehulled sesame seeds (QUALEB, 2015). The first stage of the process involves washing and drying sesame seeds using special machines to remove the sand and other
Contamination of OL aw foods with foodborne pathogens
The contamination of OL aw products foods with foodborne pathogens may occur during growth, storage or processing (Podolak et al., 2010; Sheth et al., 2011). Pathogens which were isolated from the major raw component (eg. cacao beans, sesame seeds and peanuts) of OL aw foods have also been found at the processing stage of the food chain which means that these pathogens may originate from the production environment and survive until processing (Frank, 2014). Pathogenic bacteria may contaminate
Illness outbreaks and recalls linked to OL aw foods
In recent years, low aw foods or food ingredients have been associated with foodborne illness outbreaks due to contamination with foodborne pathogens. Unfortunately, several pathogens can persist in low aw foods for months, or years, in concert with static health hazard (Beuchat et al., 2013).
The persistence of pathogens in the foods increases with decreasing aw and increasing fat content (Santillana Farakos et al., 2013). Foodborne pathogens that survive in low aw foods showed higher
Survival of pathogenic bacteria in OL aw foods
The growth or survival of pathogenic bacteria in food products is affected by various factors including the chemical and physical properties of foods (intrinsic features), storage conditions or extrinsic features, implicit features which include the physiological properties of microorganisms, as well as processing features such as heating, canning, and irradiation (Jay, 2000; Yousef and Courtney, 2003). The major intrinsic factors affecting behavior of pathogens in OL aw foods are the low aw
Bacterial responses and mechanism of survival in OL aw foods
Although there are some suggested methods by which bacteria present in an OL aw food can survive such harsh conditions, the exact mechanisms of survival are not well understood (Finn et al., 2013a). Upon exposure to the osmotic stress of low aw foods, bacteria try to overcome the stress by increasing intracellular concentrations of compatible solutes, which balance the osmolarity of the intracellular environment with that externally and thus prevent water loss. Osmoprotectants are accumulated
Control of bacterial pathogens in OL aw foods
Contamination of OL aw products with foodborne pathogens may occur during pre-processing, processing or post-processing steps (Olaimat and Holley, 2012). Therefore, control of pathogens in these products is necessary at each step of potential contamination: in the field, during harvesting, processing, distribution, retail markets, foodservice facilities, or at home to improve the safety of these products (Beuchat et al., 2013; Frank, 2014). However, preservation treatments still need to be
Sanitation, hygienic design of manufacturing facilities, good hygienic practices, environmental monitoring
OL aw producers are required to find means to prevent the occurrence of pathogenic organisms in their finished products. The potential hazards and risks throughout the manufacturing stages of these products could be eliminated through implementation of planned approaches of food safety management systems such as the International Organization for Standardization (ISO) 22000, good manufacturing practices (GMP), Good Hygienic Practices (GHP), and Hazard Analysis Critical Control Points (HACCP)
Conclusions
OL aw products have been routinely associated with large illness outbreaks and recalls, particularly involving Salmonella spp. The remarkable ability of some foodborne pathogens to survive in OL aw food products for long periods is commonly observed and is due to the high levels of fat in these foods. Although these low aw products are usually exposed to heat treatment during processing, which is sufficient to eliminate pathogens from the seed or seed coat, post-processing contamination may
Further studies
The general strategy for contamination prevention is to understand the mechanism well enough by which contamination and disease transmission can occur to interrupt them. Therefore, the effective application of control requires coordinated effort among those responsible for harvesting, processing and distribution activities. It is evident that study is required to more fully characterize the main routes by which pathogen contamination occurs in these products during production in the field and
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
References (179)
- et al.
Inhibition of Listeria innocua in hummus by a combination of nisin and citric acid
J. Food Protect.
(2006) - et al.
Use of acetic and citric acids to control Salmonella Typhimurium in tahini (sesame paste)
Food Microbiol.
(2014) - et al.
Effects of osmotic pressure, acid, or cold stresses on antibiotic susceptibility of Listeria monocytogenes
Food Microbiol.
(2015) - et al.
The effects of particle size, fermentation and roasting of cocoa nibs on supercritical fluid extraction of cocoa butter
J. Food Eng.
(2008) - et al.
Microbiological quality of tehineh manufactured in Saudi Arabia
J. Food Protect.
(1986) - et al.
Effects of gamma irradiation for inactivating Salmonella Typhimurium in peanut butter product during storage
Int. J. Food Microbiol.
(2014) - et al.
Dry stress and survival time of Enterobacter sakazakii and other Enterobacteriaceae in dehydrated powdered infant formula
J. Food Protect.
(2007) - et al.
Low–water activity foods: increased concern as vehicles of foodborne pathogens
J. Food Protect.
(2013) - et al.
A dry-inoculation method for nut kernels
Food Microbiol.
(2013) - et al.
Salmonella in sesame seed products
J. Food Protect.
(2004)
Cross-contamination and recontamination by Salmonella in foods: a review
Food Res. Int.
Antimicrobial activity of cinnamaldehyde, carvacrol, and lauric arginate against Salmonella Tennessee in a glycerol-sucrose model and peanut paste at different fat concentrations
J. Food Protect.
Colloidal stability and rheological properties of sesame paste
J. Food Eng.
Influence of water activity and storage conditions on survival and growth of proteolytic Clostridium botulinum in peanut spread
Food Microbiol.
International outbreak of Salmonella Eastbourne infection traced to contaminated chocolate
Lancet
Utilization of sunflower seeds in tahina and halawa processing
Food Chem.
Transcriptome sequencing of Salmonella enterica serovar Enteritidis under desiccation and starvation stress in peanut oil
Food Microbiol.
Effect of high hydrostatic pressure and pressure cycling on a pathogenic Salmonella serovar cocktail inoculated into creamy peanut butter
J. Food Protect.
Effect of high hydrostatic pressure on Salmonella inoculated into creamy peanut butter with modified composition
J. Food Protect.
Improving halva quality with dietary fibres of sesame seed coats and date pulp, enriched with emulsifier
Food Chem.
Outbreak of Salmonella Napoli infection caused by contaminated chocolate bars
Lancet
Sequencing and Identification of Different Salmonella species in cocoa beans treated with gamma irradiation
Procedia Food Sci
Cleaning and sanitation of Salmonella-contaminated peanut butter processing equipment
Food Microbiol.
An international outbreak of Salmonella Nima from imported chocolate
J. Food Protect.
Use of electron beam radiation for the reduction of Salmonella enterica serovars Typhimurium and Tennessee in peanut butter
J. Food Protect.
Survival of Salmonella Tennessee, Salmonella Typhimurium DT104, and Enterococcus faecium in peanut paste formulations at two different levels of water activity and fat
J. Food Protect.
Effect of growth on the thermal resistance and survival of Salmonella Tennessee and Oranienburg in peanut butter, measured by a new thin-layer thermal death time device
J. Food Protect.
Health hazard alert food recall warning - amira brand tahini sauce recalled due to Salmonella
Bacterial Pathogens in Chocolate-Based Confectionaries – April 1, 2016 to March 31, 2018, Food Microbiology – Targeted Surveys – Final Report
Salmonellosis – Outbreak Investigation February 2007
Multistate outbreak of Salmonella infections associated with peanut butter and peanut butter-containing products—United States, 2008–2009
MMWR Weekly
Multistate outbreak of Salmonella Typhimurium infections linked to peanut butter, 2008–2009 (final update)
Multistate outbreak of Salmonella Bredeney infections linked to peanut butter manufactured by Sunland, Inc. (final update)
Multistate outbreak of Salmonella serotype Bovismorbificans infections associated with hummus and tahini — United States, 2011
MMWR Weekly
Notes from the field: Salmonella Bredeney infections linked to a brand of peanut butter —United States, 2012
MMWR Weekly
Salmonella Montevideoand Salmonella Mbandakainfections linked to tahini sesame paste
Multistate outbreak of Salmonella Braenderup infections linked to nut butter manufactured by nSpired Natural Foods, Inc. (final update)
Outbreak of Salmonellainfections Linked to Tahini from Achdut Ltd
Inspection Report: FEI Number 1000117188
FDA Investigated Multistate Outbreak of E. coli O157:H7 Infections Linked to SoyNut Butter
FDA investigating a multistate outbreak of Salmonella Concord linked to tahini produced by Achdut Ltd
International outbreak of Salmonella Typhimurium DT104 – update from Norway
Wkly. Releases
Physicochemical and rheological properties of sesame pastes (tahin) processed from hulled and unhulled roasted sesame seeds and their blends at various levels
J. Food Process. Eng.
Inhibitory effect of thyme and cinnamon essential oils against E. coli O157:H7 in tahini
Food Sci. Technol.
Survival of E. coli O157:H7 and Listeria innocua in tahini (sesame paste)
J. Food Agric. Environ.
Assessing the microbial quality of tahini (sesame paste) in Lebanon
Glob. Health
Process Bulletin. Peanut Butter
Peanuts as functional food: a review
J. Food Sci. Technol.
Functionality of palm oil as a stabilizer in peanut butter
J. Food Sci.
Timing of induction of osmotically controlled genes in Salmonella enterica Serovar Typhimurium, determined with quantitative real-time reverse transcription-PCR
Appl. Environ. Microbiol.
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