Abstract：
Bacillus cereus is a well-known foodborne pathogen that can cause human diseases, including vomiting caused by emetic toxin, cereulide, requiring 105-108 cells per gram to cause the disease. The bacterial cells may be eliminated during processing, but cereulide can survive in most processing techniques due to its resistance to high temperatures, extreme pH and proteolytic enzymes. Herein, we reported dynamic processes of biofilm formation of four different types and cereulide production within the biofilm. Confocal laser scanning microscopy (CLSM) images revealed that biofilms of the four different types reach each stage at different time points. Among the extracellular polymeric substances (EPS) components of the four biofilms formed by the emetic B. cereus F4810/72 strain, proteins account for the majority. In addition, there are significant differences (p < 0.05) in the EPS components at the same stage among biofilms of different types. The time point at which cereulide was first detected in the four types of biofilms was 24 h. In the biofilm of B. cereus formed in ultra-high-temperature (UHT) milk, the first peak of cereulide appeared at 72 h. The cereulide content of the biofilms formed in BHI was mostly higher than that of the biofilms formed in UHT milk. This study contributes to a better understanding of food safety issues in the industry caused by biofilm and cereulide toxin produced by B. cereus.
摘要：
蜡样芽孢杆菌是一种众所周知的食源性病原体，可引起人类疾病，包括呕吐毒素引起的呕吐,cereulide,每克需要105-108个细胞才能导致疾病。细菌细胞可以在加工过程中消除，但是cereulide可以在大多数加工技术中存活，因为它耐高温，极端的pH和蛋白水解酶。在这里，我们报道了四种不同类型的生物膜形成的动态过程和生物膜内的cereulide生产。共聚焦激光扫描显微镜（CLSM）图像显示，四种不同类型的生物膜在不同的时间点到达每个阶段。在由催吐蜡状芽孢杆菌F4810/72菌株形成的四种生物膜的胞外聚合物(EPS)组分中，蛋白质占大多数。此外,不同类型生物膜在同一阶段的EPS组分存在显著差异(p<0.05)。在四种类型的生物膜中首次检测到蜡状芽孢杆菌的时间点为24小时。在超高温（UHT）牛奶中形成的蜡状芽孢杆菌的生物膜中，Cereulide的第一个峰出现在72h。BHI中形成的生物膜的Cereulide含量大多高于UHT牛奶中形成的生物膜。这项研究有助于更好地了解由蜡状芽孢杆菌产生的生物膜和蜡状芽孢杆菌毒素引起的行业食品安全问题。
