INRA, UMR1014 Secalim, 44322 Nantes Cedex 3, France; LUNAM Université, Oniris, Nantes, France.
CTCPA, Unité de microbiologie, ZA de l'aéroport, 84911 Avignon, France.
Int J Food Microbiol. 2014 Mar 17;174:23-30. doi: 10.1016/j.ijfoodmicro.2013.12.029. Epub 2014 Jan 7.
Foodborne botulism is a serious disease resulting from ingestion of preformed Clostridium botulinum neurotoxin in foodstuff. Since the 19th century, the heat resistance of this spore forming bacteria has been extensively studied in order to guarantee the public health associated with low acidic, ambient stable products. The most largely used heat resistance parameters in thermal settings of such products are the D121.1°C values (time required to have a 10-fold decrease of the spore count, at 121.1°C) and the z-values (temperature increase to have a 10-fold decrease of D-values). To determine D121.1°C and z-values of proteolytic C. botulinum and its nontoxigenic surrogate strain C. sporogenes PA3679, a dataset of 911 D-values was collected from 38 scientific studies. Within a meta-analysis framework, a mixed-effect linear model was developed with the log D-value (min) as response and the heat treatment temperature as explicative variable. The studies (38), the C. botulinum strains (11), and the heat treatment media (liquid media and various food matrices, split into nine categories in total) were considered as co-variables having a random effect. The species (C. botulinum and C. sporogenes) and the pH (five categories) were considered as co-variables having a fixed effect. Overall, the model gave satisfactory results with a residual standard deviation of 0.22. The heat resistance of proteolytic C. botulinum was found significantly lower than the C. sporogenes PA 3679 one: the mean D-values at the reference temperature of 121.1°C, in liquid media and pH neutral, were estimated to 0.19 and 1.28min for C. botulinum and C. sporogenes, respectively. On the other hand, the mean z-values of the two species were similar: 11.3 and 11.1°C for C. botulinum and C. sporogenes, respectively. These results will be applied to thermal settings of low-acid ambient stable products.
食源性肉毒中毒是一种严重的疾病，由摄入食品中预先形成的肉毒梭状芽孢杆菌神经毒素引起。自 19 世纪以来，为了保证与低酸性、环境稳定产品相关的公共卫生，人们广泛研究了这种产芽孢细菌的耐热性。在这些产品的热设定中，最常用的耐热性参数是 D121.1°C 值（在 121.1°C 下，芽孢数减少 10 倍所需的时间）和 z 值（温度升高 10 倍时，D 值减少所需的温度）。为了确定蛋白水解梭状芽孢杆菌及其无毒替代菌株 C. sporogenes PA3679 的 D121.1°C 和 z 值，从 38 项科学研究中收集了 911 个 D 值数据集。在荟萃分析框架内，建立了一个混合效应线性模型，以对数 D 值（min）作为响应，以热处理温度作为解释变量。研究（38 项）、梭状芽孢杆菌菌株（11 株）和热处理介质（液体介质和各种食品基质，共分为九类）被视为具有随机效应的协变量。物种（梭状芽孢杆菌和 C. sporogenes）和 pH 值（五类）被视为具有固定效应的协变量。总体而言，该模型的残差标准差为 0.22，结果令人满意。蛋白水解梭状芽孢杆菌的耐热性明显低于 C. sporogenes PA3679：在参考温度 121.1°C 下，在液体介质和中性 pH 值下，C. botulinum 和 C. sporogenes 的平均 D 值估计分别为 0.19 和 1.28min。另一方面，这两个物种的平均 z 值相似：C. botulinum 和 C. sporogenes 的平均 z 值分别为 11.3°C 和 11.1°C。这些结果将应用于低酸性环境稳定产品的热设定。
