家用洗衣机卫生现状及清洗效果的实验研究

Experimental study on sanitary status and cleaning effect of domestic washing machines

目的探究居民家用洗衣机微生物污染状况并评价专业洗衣机清洗对微生物污染的改善效果。方法在清洗前、后分别对成都市15台社区居民家用洗衣机的内筒外壁、过滤网、密封圈、洗涤剂抽屉盒和洗涤水无菌采样,共获得150份样本;检测样品细菌总数、真菌总数和大肠菌群数以反映洗衣机卫生状况,同时进行沙门氏菌、志贺氏菌和白色念珠菌的分离培养以反映致病菌污染状况;依据清洗前、后微生物检出情况和清除率综合分析洗衣机清洗效果。结果清洗前,洗衣机内细菌总数范围为1.25×10^(3)~1.19×10^(6) CFU/cm^(2);清洗后,洗衣机内细菌总数范围为0.01~375.00 CFU/cm^(2);内筒外壁、过滤网、密封圈、洗涤水和洗涤剂抽屉盒的细菌清除率分别为99.93%、99.99%、99.99%、99.74%、99.86%。清洗前,洗衣机内真菌总数范围为8.50~9.45×10^(3)CFU/cm^(2);清洗后,洗衣机内真菌总数范围为0~49.22 CFU/cm^(2);内筒外壁、过滤网、密封圈、洗涤水和洗涤剂抽屉盒的真菌清除率分别为99.36%、99.74%、99.76%、99.51%、99.64%。清洗前,洗衣机内大肠菌群数范围为0~4.6×10^(4)MPN/100 ml;清洗后,大肠菌群数均接近于0。清洗前,洗衣机内沙门氏菌平均检出率为5.33%,志贺氏菌平均检出率为2.67%,未检出白色念珠菌;清洗后,均未检出沙门氏菌、志贺氏菌和白色念珠菌。结论本研究的家用洗衣机清洗前细菌和真菌数量较大,且存在沙门氏菌和志贺氏菌污染,专业清洗后洗衣机卫生状况明显改善。

Objective To explore the microbial contamination status of household washing machines and evaluate the improvement effect of professional washing machine cleaning on microbial contamination.Methods Before and after cleaning,samples were collected asepticly from the outer wall of the inner cylinder,filter,sealing ring,detergent drawer box and washing water of 15 household washing machines,thus,a total of 150 samples were obtained.The total number of bacteria,fungi and coliform were detected to reflect the hygiene status of the washing machine.At the same time,Salmonella,Shigella and Candida albicans were isolated and cultured to reflect the contamination status of pathogenic bacteria.According to the detection and clearance rate of microorganisms,the cleaning effects of washing machine were comprehensively analyzed.Results Before washing,the total number of bacteria in the washing machine ranged from 1.25×10^(3) to 1.19×10^(6) CFU/cm^(2).After washing,the total number of bacteria in the washing machine ranged from 0.01 to 375 CFU/cm^(2).The bacterial clearance rates of the outer wall of the inner cylinder,the filter,the sealing ring,the washing water and the detergent drawer box were 99.93%,99.99%,99.99%,99.74%and 99.86%,respectively.Before washing,the total number of fungi in the washing machine ranged from 8.5 to 9.45×10^(3) CFU/cm^(2).After washing,the total number of fungi in the washing machine ranged from 0 to 49.22 CFU/cm^(2).The fungal clearance rates of the outer wall of the inner cylinder,filter screen,seal ring,washing water and detergent drawer box were 99.36%,99.74%,99.76%,99.51%and 99.64%,respectively.Before washing,the coliforms in the washing machine ranged from 0 to 4.6×10^(4) MPN/100 ml.After washing,the number of coliform bacteria was close to 0.Before washing,the average detection rate of Salmonella in the washing machine was 5.33%,the average detection rate of Shigella was 2.67%,and no Candida albicans was detected.After washing,Salmonella,Shigella and Candida albicans were not detected.Conclusion There are a large number of bacteria and fungi in the household washing machine before cleaning,and there are Salmonella and Shigella contamination.After professional cleaning,the hygiene condition of the washing machine is significantly improved.