市售鲜湿米粉菌落总数及大肠菌群数繁殖动态的考察

Investigation on the total number of bacterial colonies and the breeding dynamics of coliform bacteria in fresh wet rice noodles sold in the market

目的考察南宁市售不同厂家的鲜湿类米粉的菌落总数、大肠菌群污染状况及后续繁殖动态。方法按照GB4789.1-2016《食品安全国家标准食品微生物学检验总则》抽样方法,从餐饮店抽取6批不同厂家的未开封的鲜湿米粉。按照GB4789.2-2016《食品安全国家标准食品微生物学检验菌落总数测定》、GB4789.3-2016《食品安全国家标准食品微生物学检验大肠菌群计数》的检测方法,分别在0、2、4、8、12、16、24h对样品的菌落总数及大肠菌群项目进行检测,在24h同时取部分样品在沸水中焯1min后平行检测,对计数结果进行分析。结果0h时,各样品的菌落总数在3.1×10^3~6.9×10^7CFU/g,大肠菌群在0~8.5×10^5CFU/g。在22℃条件放置下,随着时间推移,各样品的菌落总数和大肠菌群数仍不断增殖。16h(即保质期过后),菌落总数达到7.2×10^7~1.9×10^9CFU/g左右,繁殖基本趋缓。24h时,在沸水中焯1min后,所有样品的菌落总数小于1.3×10^3CFU/g,大肠菌群均小于10CFU/g,远低于标准规定。结论22℃储藏条件下并不能遏制鲜湿米粉的菌落总数及大肠菌群增殖,沸水焯1min可有效降至安全水平。

Objective To investigate the total number of colonies,coliform contamination and subsequent reproductive dynamics of fresh wet rice noodles sold by different manufacturers in Nanning.Methods According to GB 4789.1-2016 National food safety standard-Microbiology inspection-General principles sampling method,6 batches of unopened fresh wet rice noodles from different manufacturers were taken from the restaurant.According to GB 4789.2-2016 National food safety standard-Food microbiology test-Detection of aerobic bacterial count,and GB 4789.3-2016 National food safety standard-Food microbiology test-Enumeration of coliforms,the total number of colonies and coliforms of the samples were detected at 0,2,4,8,12,16 and 24 h,respectively.At 24 h,some samples were simultaneously blanched in boiling water for 1 min and then tested in parallel to analyze the counting results.Results At 0 h,the total numbers of colonies of sample were 3.1×10^3 to 6.9×10^7 CFU/g,and the coliform groups were 0 to 8.5×10^5 CFU/g.Under the conditions of 22℃,the total number of colonies and the number of coliforms of each sample continued to proliferate over time.After 16 h(that was,after the shelf life),the total numbers of colonies reached 7.2×10^7~1.9×10^9 CFU/g,and the reproduction basically slowed down.At 24 h,after 1 min in boiling water,the total numbers of colonies of all samples were less than 1.3×10^3 CFU/g,and the coliform groups were less than 10 CFU/g,which was far below the standard.Conclusion Under the storage condition of 22℃,the total number of colonies of fresh wet rice noodles and the proliferation of coliform bacteria can not be suppressed.It can be effectively reduced to a safe level after boiling in boiling water for 1 min.