鸡是可疑的尿路致病性大肠杆菌(UPEC)的水库,导致食源性尿路感染(UTI)。由于低温长时间(LTLT)过程,Sous-vide即食(RTE)食品可能与微生物危害有关。然而,关于UPEC在sous-vide烹饪过程中的存活情况知之甚少。本研究的目的是评估UPEC在鸡胸肉中的耐热性,并建立预测灭活模型。用UPEC的四菌株混合物接种鸡胸肉样品,包括来自UTI患者和鸡分离株的参考菌株。接种的样品,含或不含3%NaCl溶液进行腌制,真空密封在袋子里,浸入温控水浴中,并在50°C下煮熟,55°C,60°C,63℃用线性和Weibull失活模型拟合UPEC种群的生存变化,以获得不同温度下的生存曲线;还计算了D值和z值。拟合优度使用均方根误差(RMSE)进行评估,误差平方和(SSE),调整后的R2和Akaike信息标准(AIC)。结果表明,带尾线性模型的拟合性能优于Weibull模型。加入盐腌料,50°C时的D值,55°C,60°C,由尾部线性模型确定的63°C从299.78分钟降低到166.93分钟,16,60至13.87分钟,4.06至3.05min,和1.05到0.87分钟,分别,与对照组相比。对照和盐腌制样品的z值分别为6.14°C和5.89°C,分别。在58°C下使用额外的存活曲线验证了用于预测Sous-Vide烹饪下UPEC存活率的模型。验证结果表明,RMSE为0.122和0.133logCFU/g,对照和盐渍样品在可接受的预测区中的相对误差比例为0.875和0.750,分别。总之,一种新兴的食源性病原体的耐热性,UPEC,在苏维德加工鸡胸肉首次被揭露。我们的结果表明,盐腌泡汁(3%NaCl)在sous-vide加工过程中增加了UPEC的热敏感性。基于带尾线性模型开发的生存函数可用于控制UPEC的热致死性。
Chicken is a suspected reservoir of uropathogenic Escherichia coli (UPEC), resulting in foodborne urinary tract infections (UTIs). Sous-vide ready-to-eat (RTE) food products may be associated with microbial hazards due to the low-temperature long-time (LTLT) process. However, little is known regarding the survival of UPEC during sous-vide cooking. The aim of this study was to evaluate the heat resistance of UPEC in chicken breast during sous-vide processing and establish predictive inactivation models. Chicken breast samples were inoculated with a four-strain cocktail of UPEC, including reference strains from UTI patients and chicken isolates. The inoculated samples, with or without 3% NaCl solution for marination, were vacuum sealed in bags, immersed in a temperature-controlled water bath, and cooked at 50 °C, 55 °C, 60 °C, and 63 °C. The change in survival of populations of UPEC was fitted with the linear and Weibull inactivation models to obtain the survival curves at different temperatures; the D- and z-values were also calculated. The goodness-of-fit was evaluated using the root mean square error (RMSE), sum of squared errors (SSE), adjusted R2, and Akaike information criterion (AIC). The results showed that the linear model with tail was better than the Weibull model in terms of fitting performance. With the addition of salt marinade, D-values at 50 °C, 55 °C, 60 °C, and 63 °C determined by the linear model with tail decreased from 299.78 to 166.93 min, 16,60 to 13.87 min, 4.06 to 3.05 min, and 1.05 to 0.87 min, respectively, compared with the controls. The z-values of control and salt-marinated samples were 6.14 °C and 5.89 °C, respectively. The model developed for predicting UPEC survival under sous-vide cooking was validated using an additional survival curve at 58 °C. The validation results showed that the RMSE was 0.122 and 0.133 log CFU/g, and the proportion of relative error was 0.875 and 0.750 in the acceptable prediction zones for the control and salt-marinated samples, respectively. In conclusion, the heat resistance of an emerging foodborne pathogen, UPEC, in sous-vide processed chicken breast was revealed for the first time. Our results showed that salt marinade (3% NaCl) increases the heat sensitivity of UPEC during the sous-vide processing. The developed survival functions based on the linear model with tail can be applied to control the thermal lethality of UPEC.