摘要
以一株蜡样芽孢杆菌为研究对象,其产毒基因以及产毒类型通过ELISA以及PCR鉴定,而后将其接种到米饭中并混合均匀,置于不同的温度条件下培养,温度分别设置为(10.0±0.2),(15.0±0.2),(20.0±0.2),(25.0±0.2),(30.0±0.2),(35.0±0.2)℃,研究其在米饭中生长以及产毒情况。采用修正的Gompertz模型构建初级生长模型,并在此基础进行产毒预测。结果表明,该株蜡样芽胞杆菌具有致泻型肠毒素基因,在15~35℃范围内该株菌在米饭中可产生肠毒素,随着培养温度的下降,开始产生毒素的时间也随之推迟;通过间隔取样检测到最初产毒素时的菌落总数范围为6.5~7.0 lg(CFU/g),采用插值计算校正后得到的实际开始产毒素时菌落总数范围为5.5~6.0 lg(CFU/g)。由于试验结果显示在15~35℃温度范围内蜡样芽胞杆菌是否产毒与其达到的浓度(菌落总数)有直接的相关性,因此从生长预测模型预测到的菌落数可用于判断产生毒素的风险程度。
In this paper,the type of Bacillus diarrhoeal enterotoxin gene of a Bacillus cereus spp.was identified by PCR and ELISA,this strain was also inoculated into cooked rice and stored at various temperature of（10.0±0.2）,（15.0±0.2）,（20.0±0.2）,（25.0±0.2）,（30.0±0.2）,（35.0±0.2）℃ separately.Duplicate samples were analyzed to count the number of colonies and detect the Bacillus diarrhoeal enterotoxin.The modified Gompertz model was used to describe the Bacillus cereus spp.growth in cooked rice,the enterotoxigenic prediction was then carried out one the basis of its primary model.The results showed that this Bacillus cereus spp.contains Bacillus diarrhoeal enterotoxin gene and could produce diarrhea Bacillus diarrhoeal enterotoxin in cooked rice under the temperature of 15-35 ℃,however the Bacillus diarrhoeal enterotoxin was become later to be detected with the temperature decreased.The result of duplicate samples showed that the population of Bacillus cereus spp.in cooked rice was 6.5-7.0 lg（CFU/g）,where the Bacillus diarrhoeal enterotoxin could be detected.When the interpolation calculation was used to calibrate the time when the Bacillus diarrhoeal enterotoxin could be detected,the population of Bacillus cereus spp.was then shifted to 5.5-6.0 lg（CFU/g）.The result of this study also indicated that the population of Bacillus cereus spp.had correlation with the enterotoxigenic production,so the population of Bacillus cereus spp.obtained from the primary model may be used to predicate the risk of the enterotoxigenic production.
出处
《中国食品学报》
EI
CAS
CSCD
北大核心
2017年第1期230-239,共10页
Journal of Chinese Institute Of Food Science and Technology
基金
上海市科委应用技术开发专项(2013-116
2014-110)
关键词
蜡样芽胞杆菌
致泻肠毒素
生长模型
产毒预测
Bacillus cereus spp
Bacillus diarrhoeal enterotoxin
primary model
enterotoxigenic prediction
