北京市售巴氏杀菌乳的消费调查及实验验证研究

Consumption survey and experimental verification study of pasteurized milk in Beijing

目的了解北京地区消费者巴氏杀菌乳的消费习惯,评估储存温度和时间对巴氏杀菌乳中微生物数量的影响,为消费者正确储存巴氏杀菌乳提供依据。方法北京10个行政区各选择1个大型超市进行问卷调查,调查内容包括巴氏杀菌乳的饮用频率、储存温度和时间等。依据调查结果模拟消费者储存条件,结合微生物生长规律,采用正交试验方法探究温度和时间对巴氏杀菌乳中菌落总数及金黄色葡萄球菌(Staphylococcusaureus)数量的影响。结果调查问卷结果表明,18岁以下、18~54岁和55岁以上的消费者中,每天饮用巴氏杀菌乳的比例最高分别为15.4%、49.0%和75.9%;所调查消费者中,将巴氏杀菌乳储存在2~6℃、室温、-20℃的比例分别为75.0%、14.6%、5.5%;模拟实验结果表明储存温度对巴氏杀菌乳中微生物影响更大,37℃储存48 h后,菌落总数和S.aureus数量达到1.26×10^5 CFU/mL和1.20×10^4 CFU/mL。结论北京市饮用巴氏杀菌乳的消费者主要集中在中老年人群;部分消费者(24.2%)不明确巴氏杀菌乳的正确储存温度;不当的储存温度导致巴氏杀菌乳中的菌落总数和金黄色葡萄球菌的数量增加。

Objective To understand the consumption habits of pasteurized milk of consumers in Beijing, evaluate the impact of storage temperature and time on the number of microorganisms in pasteurized milk, and provide a basis for consumers to properly store pasteurized milk. Methods A large supermarket in each of Beijing's 10 administrative regions was selected for the questionnaire survey, which included the drinking frequency, storage temperature and time of pasteurized milk. Based on the results of the investigation, the effects of temperature and time on the total number of bacterial colonies and Staphylococcus aureus in pasteurized milk were studied by means of orthogonal test in combination with the simulated storage conditions of consumers and the growth rules of microorganisms. Results The results of the questionnaire showed that among consumers under 18 years old, 18-54 years old and over 55 years old, the maximum proportion of daily consumption of pasteurized milk were 15.4%, 49.0% and 75.9%, respectively. Among the consumers surveyed, the percentages of sterilized milk stored at 2-6 °C,room temperature and -20 °C were 75.0%, 14.6% and 5.5%, respectively. The simulation results showed that the storage temperature had more effect on microorganism in pasteurized milk, and the total number of colonies and S. aureus number were 1.26×10^5 CFU/mL and 1.20×10^4 CFU/mL after storage at 37 °C for 48 h. Conclusion The consumers of pasteurized milk in Beijing are mainly middle-aged and elderly people, and some consumers (24.2%) do not know the correct storage temperature of pasteurized milk. Improper storage temperature leads to an increase in the total number of bacteria and Staphylococcus aureus in pasteurized milk.