肉制品中产气荚膜梭菌的形成与调控机制研究

Clostridium perfringens is an anaerobic growth and produce toxins, it is considered as one of the most common pathogen causes of food poisoning. But it is difficult for C. perfringens spores to inactivate in normal cooking conditions of meat products. Instead, cooking may activate the spores, which can germinate and outgrow during cooling. Potential safety hazard is serious. Therefore, study on the formation and regulatory mechanism of C.perfringens is of great significance to improve the level of meat safety and public health. Firstly, the effect factor of formation and growth of C. perfringens would be confirmed by electronic speculum and PCR in the project. Then, growth characteristic of C. perfringens on dynamic change would be studied using anaerobic culture method. The tertiary model in one step of C.perfringens would be built combined with computer program simulation and numerical optimization method. And validate the model under both dynamic and isothermal conditions. Finally, based on the prediction model, probability of relative growth of C.perfringens would be obtained by calculate and analyze the probability of relative growth using stochastic simulation program. The formation and regulatory mechanism of C.perfringens in meat product would be revealed combined with its effect factor of formation and growth. This project would provide theoretical foundation and scientific basis for directional control of C.perfringens in meat products, and provide ideas and methods for the research on the safety of food microbiology.

产气荚膜梭菌（Clostridium perfringens）在厌氧环境中生长且产毒，是引起食源性疾病最常见病原菌之一。而肉制品中C.perfringens芽孢失活难，且易被激活和萌发，安全隐患大，开展肉制品中C.perfringens形成和调控机制研究对提高肉品安全和公众健康水平具有重要意义。本项目首先应用电镜、PCR等技术确定影响肉制品中C.perfringens形成和生长的因素；其次，应用厌氧培养法研究其动态变化时生长特性，通过计算机程序模拟与数值优化法结合一步构建其动态变化预测模型，并验证动态和等温状态；最后，基于构建预测模型采用随机方法和计算机程序计算和分析获得其相对生长量的概率，并结合影响其形成和生长因素揭示肉制品中C.perfringens的形成和调控机制，为肉制品中C.perfringens的定向调控提供理论基础和科学依据，也为食品微生物安全性研究提供新思路和方法。

产气荚膜梭菌（Clostridium perfringens）是广泛分布环境中能够快速生长，极易产毒的厌氧芽孢菌，且是引起食源性疾病的常见致病菌之一。在肉制品中热加工后的冷却为其芽孢萌发，生长和繁殖提供了机会，导致肉制品安全存在极大隐患。本项目通过不同温度和精油等处理，确定影响肉品中芽孢萌发和生长的主要因素是热处理后冷却过程中温度和时间；热激可显著诱导芽孢萌发，最适热激温度为75℃。基于此，研究热处理-冷却条件下肉制品中C. perfringens动态生长特性，然后通过计算机程序模拟与四阶龙格库塔（RK4）数值优化法结合，一步构建真空包装肉制品在不同动态冷却下动态模型，通过RMSE和残差等分析确定模型准确度高。.最后，通过高性能各向异性的微分积分数值解析，创新设计自身特色的数值解析软件解析其相对生长量的概率，C.perfringens相对生长量控制在1 log CFU/g内可保证肉制品安全，烧鸡55-27℃冷却时间需控制在1h，27-4℃控制在3h以内；酱牛肉制品55-27℃冷却时间在1h内，27-4℃控制在2.7h，总时间控制在3.7h内可保证酱牛肉安全；通过相对生长量的概率解析，构造出C. perfringens复杂变化下的温度-时间双参数优化与调控新模式，突破冷却调控科学理论难题，揭示肉制品中C. perfringens的形成与调控机制，解决了准确而科学控制产业加工中安全隐患难题，对食品安全控制具有重大支撑作用，对丰富和发展各向异性非线性双参数的内涵有着重要的理论意义和应用价值。.另外，本项目研究中发现，无论是何种诱导芽孢萌发的因素包括营养/非营养因子等都是先通过热激诱导芽孢萌发，而C. perfringens芽孢如何感应热激和诱导萌发尚未可知，值得进一步研究。