Microbial contamination of online ordering takeout food in Guangzhou in 2017
2017年3月、6-9月及11月在广州市10个区通过在网络外卖平台订购的方式采集米饭加菜类、寿司手卷类、紫菜包饭类及热汤粉面类4个类别的网络外卖配送餐样品856份，按GB 4789《食品安全国家标准食品微生物学检验》规定的方法对样品开展菌落总数、大肠埃希氏菌及常见食源性致病菌（沙门氏菌、金黄色葡萄球菌、蜡样芽孢杆菌、单核细胞增生李斯特氏菌与副溶血性弧菌）项目的检测。参照DBS 44/006-2016《广东省食品安全地方标准非预包装即食食品微生物限量》对检验结果进行评价，如样品中任一项目达"不合格"限量标准，则该样品判为不合格。基于广州各区地理位置、人口分布等因素将采样区域分为城区和城郊区，并对结果进行分析。
χ2=11.744， P=0.001）。不同类别样品间检测微生物不合格率差异有统计学意义（ χ2=40.481， P=0.001）；紫菜包饭类大肠埃希氏菌不合格率最高，达47.96%（47/98）；米饭加菜类菌落总数不合格率最高，为19.93%（111/557）。夏秋季（6-9月）样品检测微生物不合格率28.67%（164/572）高于冬春季（3月与11月）19.72%（56/284）（ χ2=7.966， P=0.005）。 结论
In recent years, "online ordering takeout food" has become popular among various customer groups such as students and office workers and part of daily life for the residents in Guangzhou. Recent frequent incidents concerning online ordering takeout food safety and hygiene have aroused public concern. However, its microbial contamination is rarely studied.
This study is designed to investigate the microbial contamination status of online ordering takeout food in Guangzhou, and provide evidence for the food safety supervision and further research on online ordering takeout food.
A total of 856 samples of four kinds of takeout food including Chinese box food, sushi, gimbap, and noodle with hot soup were collected through online ordering in 10 districts of Guangzhou in March, June to September, and November of 2017. Examinations of total aerobic bacteria,
Escherichia coli, and five common foodborne pathogens ( Salmonella, Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes, and Vibrio parahaemolyticus) were carried out according to standard microbiological testing methods stipulated by the GB 4789 National Food Safety Standards:Food Microbiological Examination. According to the DBS 44/006-2016 Local Standards of Food Safety in Guangdong Province:Microbial Limits of Non-prepackaged Ready-to-eat Food, the samples were evaluated and categorized as disqualified if the count of any pathogens reached the "unqualified" limit. Base on geographical location and population distribution, the sample sites were divided into suburban and downtown areas, and the results were analyzed. Results
The overall unqualified rate of selected microbial indicators online ordering takeout food samples was 25.70% (220/856), and the most prevalent pathogens were
Escherichia coli(17.52%, 150/856), followed by total aerobic bacteria (14.72%, 126/856), and foodborne pathogens (1.17%, 10/856). The unqualified rate was significantly higher in samples from downtown areas (28.78%, 181/629) than in those from suburban areas (17.18%, 39/227) ( χ2=11.744, P=0.001). There was a significant difference in the unqualified rate among different food types ( χ2=40.481, P=0.001), with the highest prevalence rates of Escherichia coliand total aerobic bacteria found in gimbap (47.96%, 47/98) and Chinese box food (19.93%, 111/557) samples, respectively. A significantly higher unqualified rate was found during summer and autumn (from June to September, 28.67%, 164/572) than during spring and winter (March and November, 19.72%, 56/284) ( χ2=7.966, P=0.005). Conclusion
Poor sanitary conditions due to microbial contamination are generally found in online ordering takeout food in Guangzhou. It is urgent for relevant government departments to strengthen the hygienic supervision and monitoring of online ordering takeout food.