Division of Food Processing Science and Technology, U. S. Food and Drug Administration, Bedford Park, Illinois, United States of America.
Institute for Food Safety and Health, Illinois Institute of Technology, Bedford Park, Illinois, United States of America.
PLoS One. 2020 Jun 30;15(6):e0235472. doi: 10.1371/journal.pone.0235472. eCollection 2020.
Refrigerated ready-to-eat (RTE) dips often have pH and water activity combinations conducive to the proliferation of foodborne pathogens, including Listeria monocytogenes. This study conducted product assessments of five refrigerated RTE dips: baba ghanoush, guacamole, hummus, pesto, and tahini, along with individual dip components including avocado, basil, chickpeas, cilantro, eggplant, garlic, and jalapeno pepper. Dips and dip components were inoculated with 2 log CFU/g of L. monocytogenes and stored at 10°C for 28 days. The pathogen was enumerated throughout storage and growth rates were determined using the DMFit program to compute the time required for L. monocytogenes to achieve a 1 log CFU/g increase in population. Survival and growth rates varied significantly between the refrigerated RTE dips and dip components assessed in this study. For dips, L. monocytogenes progressively decreased in baba ghanoush, pesto, and tahini. In contrast, the pathogen proliferated in both hummus and guacamole and the highest growth rate was observed in guacamole (0.34±0.05 log CFU/g per day) resulting in a 1 log CFU/g increase in population in 7.8 days. L. monocytogenes proliferated in all dip components with the exception of eggplant and garlic. The pathogen achieved the highest growth rate in chickpeas (2.22±1.75 log CFU/g per day) resulting in a computed 1 log CFU/g increase in only 0.5 days. Results from this study can aid in understanding how L. monocytogenes behaves in refrigerated RTE dips and dip components and data can be utilized in understanding product formulations and in risk assessments.
冷藏即食（RTE）蘸酱通常具有有利于食源性病原体（包括单核细胞增生李斯特菌）增殖的 pH 值和水活度组合。本研究对五种冷藏 RTE 蘸酱：茄子泥、鳄梨酱、鹰嘴豆泥、香蒜酱和芝麻酱，以及包括鳄梨、罗勒、鹰嘴豆、香菜、茄子、大蒜和墨西哥胡椒在内的单个蘸酱成分进行了产品评估。将蘸酱和蘸酱成分接种 2 log CFU/g 的单核细胞增生李斯特菌，并在 10°C 下储存 28 天。在整个储存过程中对病原体进行计数，并使用 DMFit 程序确定生长速率，以计算单核细胞增生李斯特菌实现种群增加 1 log CFU/g 所需的时间。在本研究中评估的冷藏 RTE 蘸酱和蘸酱成分之间，生存和生长速率差异显著。对于蘸酱，单核细胞增生李斯特菌在茄子泥、香蒜酱和芝麻酱中逐渐减少。相比之下，病原体在鹰嘴豆泥和鳄梨酱中增殖，在鳄梨酱中观察到最高的生长速率（每天 0.34±0.05 log CFU/g），导致种群增加 1 log CFU/g 仅需 7.8 天。单核细胞增生李斯特菌在除茄子和大蒜以外的所有蘸酱成分中均增殖。病原体在鹰嘴豆中达到最高的生长速率（每天 2.22±1.75 log CFU/g），仅需 0.5 天即可计算出 1 log CFU/g 的增加。本研究的结果可以帮助理解单核细胞增生李斯特菌在冷藏 RTE 蘸酱和蘸酱成分中的行为，并且数据可用于理解产品配方和风险评估。
