灭菌乳中嗜热脂肪芽孢杆菌商业无菌的最低可视浓度的测定

Determination of the lowest visible concentration of commercial sterility of Geobacillus stearothermophilus in sterilized milk

中文关键词:  灭菌乳  嗜热脂肪芽孢杆菌  商业无菌  检出限  漏检

英文关键词:sterilized milk  Geobacillus stearothermophilus  commercial sterility  limit of detection  missed detection

中文摘要:

      目的 测定灭菌乳中嗜热脂肪芽孢杆菌的商业无菌最低可视浓度。方法 随机购买3种不同品牌的灭菌乳, 分别添加105、104、103、102、101、100 CFU/mL浓度的嗜热脂肪芽孢杆菌制成模拟样品, 分别对培养4、7、9、10 d的样品按照GB 4789.26-2013《食品安全国家标准 食品微生物学检验 商业无菌检验》的检验方法检测。结果 培养7 d和10 d后的3种品牌模拟样品从编号(X-1)-(X-5)(X代表表1中样品信息编号)均可在视野范围内观察到嗜热脂肪芽孢杆菌, 同时镜检发现培养10 d后样品中的嗜热脂肪芽孢杆菌并无百倍或百倍以上增殖也无菌落形成芽孢。对培养10 d后的模拟样品进行菌落计数验证以上结论。结论 灭菌乳中嗜热脂肪芽孢杆菌商业无菌最低可视浓度为101 CFU/mL。灭菌乳中嗜热脂肪芽孢杆菌在培养10 d后无明显增殖, 也无菌落进入休眠状态。表明灭菌乳中污染嗜热脂肪芽孢杆菌符合商业无菌相对无菌标准。

英文摘要:

      Objective To determine the lowest visible concentration of commercial sterility of Geobacillus stearothermophilus in sterilized milk. Methods Three different brands of sterilized milk were randomly purchased, after adding 105, 104, 103, 102, 101, 100 CFU/mL concentration Geobacillus stearothermophilus to make a simulated sample, the samples cultured for 4, 7, 9, and 10 d were tested according to the inspection method of GB 4789.26-2013 National food safety standard-Food microbiological inspection-Commercial sterility inspection. Results After 7 d and 10 d of cultivation, the 3 brand simulation samples from number (X-1) to (X-5) (X represents the sample information number in Table 1) could all be observed in the field of view of Geobacillus stearothermophilus, at the same time, it was found that the Geobacillus stearothermophilus in the sample after 10 days of culture did not multiply a hundred times or more, and did not produce spores. Colony counts were performed on the simulated samples after 10 days of culture to verify the above conclusions. Conclusion The lowest commercial sterile concentration of Geobacillus stearothermophilus in sterilized milk is 101 CFU/mL. Geobacillus stearothermophilus in the sterilized milk do not proliferate significantly after 10 days of culture, and no colony enteres a dormant state. It showes that the contaminated Geobacillus stearothermophilus in the sterilized milk meets the commercial sterility relative sterility standard.