Microbial Risk Analysis ( IF 2.8 ) Pub Date : 2021-09-02 , DOI: 10.1016/j.mran.2021.100177 Gabriela Orosco Werlang 1 , Tatiana Regina Vieira 1 , Marisa Cardoso 1 , Eduardo de Freitas Costa 2
The microbiological quality of fermented products such as salami are highly dependent on the interaction of environmental conditions during its fabrication. These effects may be predicted by mathematical modeling, and this approach has been adopted in several occasions. The aim of this study was to validate the Gamma concept model to predict Salmonella behavior during salami manufacturing in environmental conditions found in small scale Brazilian manufacturer. Furthermore, we simulated the growth and inactivation of Salmonella in salami considering a Brazilian scenario of contamination level of pork. Salami pieces were elaborated with a cocktail of five strains of Salmonella and subjected to maturation. For the fitted model construction, temperatures of 30°C during fermentation and 20°C during drying were used; while 25°C (fermentation) and 18°C (drying) were used in the validation study. Water activity (aw) and pH were analyzed and Salmonella enumerated during maturation for fitting the curves. Salmonella isolates recovered at the end of the maturation were subjected to macrorestriction profiling (PFGE). The parameters obtained in the fitted Gamma concept model (μopt, δ1, δ2, α) were used to predict the bacteria behaviour in the validation study. During the maturation, Salmonella concentration decreased from 7.086 to 3.368 log10 cfu/g (after 941 horas), and from 7.751 to 2.749 log10 cfu/g (after 1121.5 horas) in the fitted model and validation study, respectively. The aw was determinant for starting the microbial inactivation in the fitted model. Strains belonging to all PFGE-profiles inoculated in the salami pieces were detected in the end of the maturation. Regarding the simulation in a Brazilian scenario of pork contamination, the model predicted, in the upper 95% confidence interval, zero log10 cfu/g of Salmonella after 670 h of maturation. The results indicate that the Gamma concept model provide a robust alternative to predict the concentration of Salmonella in salami considering the characteristics of production adopted in small industries in Brazil. The model predicted that in a scenario of higher environmental temperatures (30°C fermentation/ 20°C drying) Salmonella absence can be achieved after 15 days.
中文翻译:
在巴西小规模制造商的环境条件下,在意大利腊肠的整个制造过程中应用预测微生物模型来估计沙门氏菌行为
意大利腊肠等发酵产品的微生物质量在很大程度上取决于其制造过程中环境条件的相互作用。这些影响可以通过数学建模来预测,并且这种方法已被多次采用。本研究的目的是验证 Gamma 概念模型,以预测在巴西小规模制造商发现的环境条件下意大利腊肠制造过程中的沙门氏菌行为。此外,考虑到巴西猪肉污染水平,我们模拟了意大利腊肠中沙门氏菌的生长和灭活。意大利腊肠片是用五种沙门氏菌的鸡尾酒制成的并经过成熟。对于拟合模型构建,发酵过程中的温度为 30°C,干燥过程中的温度为 20°C;而验证研究中使用了 25°C(发酵)和 18°C(干燥)。分析水分活度 (a w ) 和 pH 值,并在成熟过程中对沙门氏菌进行计数以拟合曲线。在成熟结束时回收的沙门氏菌分离物进行宏观限制分析 (PFGE)。在拟合 Gamma 概念模型中获得的参数(μ opt、δ1、δ2、α)用于预测验证研究中的细菌行为。在成熟过程中,沙门氏菌浓度从 7.086 下降到 3.368 log 10cfu/g(在 941 horas 之后),以及在拟合模型和验证研究中分别从 7.751 到 2.749 log 10 cfu/g(在 1121.5 horas 之后)。a w是拟合模型中开始微生物灭活的决定因素。在成熟结束时检测到属于所有 PFGE 谱的菌株接种在意大利腊肠片中。关于巴西猪肉污染情景中的模拟,该模型预测,在 95% 置信区间的上限,沙门氏菌在成熟 670 小时后为零 log 10 cfu/g 。结果表明 Gamma 概念模型提供了一种可靠的替代方法来预测沙门氏菌的浓度考虑到巴西小工业采用的生产特征,在意大利腊肠中。该模型预测,在环境温度较高(30°C 发酵/20°C 干燥)的情况下,15 天后可以消除沙门氏菌。