CIISA - Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, Avenida da Universidade Técnica, Lisboa, 1300-477, Portugal.
Risk Anal. 2020 Nov;40(11):2427-2441. doi: 10.1111/risa.13546. Epub 2020 Jul 1.
Currently, there is a growing preference for convenience food products, such as ready-to-eat (RTE) foods, associated with long refrigerated shelf-lives, not requiring a heat treatment prior to consumption. Because Listeria monocytogenes is able to grow at refrigeration temperatures, inconsistent temperatures during production, distribution, and at consumer's household may allow for the pathogen to thrive, reaching unsafe limits. L. monocytogenes is the causative agent of listeriosis, a rare but severe human illness, with high fatality rates, transmitted almost exclusively by food consumption. With the aim of assessing the quantitative microbial risk of L. monocytogenes in RTE chicken salads, a challenge test was performed. Salads were inoculated with a three-strain mixture of cold-adapted L. monocytogenes and stored at 4, 12, and 16 °C for eight days. Results revealed that the salad was able to support L. monocytogenes' growth, even at refrigeration temperatures. The Baranyi primary model was fitted to microbiological data to estimate the pathogen's growth kinetic parameters. Temperature effect on the maximum specific growth rate (μ ) was modeled using a square-root-type model. Storage temperature significantly influenced μ of L. monocytogenes (p < 0.05). These predicted growth models for L. monocytogenes were subsequently used to develop a quantitative microbial risk assessment, estimating a median number of 0.00008726 listeriosis cases per year linked to the consumption of these RTE salads. Sensitivity analysis considering different time-temperature scenarios indicated a very low median risk per portion (<-7 log), even if the assessed RTE chicken salad was kept in abuse storage conditions.
目前，人们越来越喜欢方便食品，如即食（RTE）食品，这些食品具有较长的冷藏保质期，在食用前不需要进行热处理。由于单核细胞增生李斯特菌能够在冷藏温度下生长，在生产、配送和消费者家庭中温度不一致可能会使病原体大量繁殖，达到不安全的限度。单核细胞增生李斯特菌是李斯特菌病的病原体，这是一种罕见但严重的人类疾病，死亡率很高，几乎完全通过食物摄入传播。为了评估 RTE 鸡肉沙拉中单核细胞增生李斯特菌的定量微生物风险，进行了一项挑战试验。沙拉用适应寒冷的单核细胞增生李斯特菌三菌株混合物接种，并在 4、12 和 16°C 下储存八天。结果表明，即使在冷藏温度下，沙拉也能够支持单核细胞增生李斯特菌的生长。Baranyi 主要模型被拟合到微生物数据中，以估计病原体的生长动力学参数。使用平方根模型对温度对最大比生长速率（μ）的影响进行建模。储存温度显著影响单核细胞增生李斯特菌的μ（p<0.05）。这些预测的单核细胞增生李斯特菌生长模型随后用于开发定量微生物风险评估，估计每年与食用这些 RTE 沙拉相关的李斯特菌病病例中位数为 0.00008726 例。考虑不同时间-温度情景的敏感性分析表明，即使评估的 RTE 鸡肉沙拉处于滥用储存条件下，每份的风险中位数也非常低（<-7 log）。
