Center for Food Safety, University of Georgia, Griffin, GA 30223, USA.
J Food Prot. 2012 Aug;75(8):1437-46. doi: 10.4315/0362-028X.JFP-12-052.
Human noroviruses (NoVs) cause an estimated 58% of foodborne illnesses in the United States annually. The majority of these outbreaks are due to contamination by food handlers. The objective of this study was to quantify the transfer rate and degree of contamination that occurs on small fruits (blueberries, grapes, and raspberries) and food contact surfaces (stainless steel) when manipulated with NoV-contaminated hands. Human NoVs (genogroups I and II [GI and GII]) and murine norovirus (MNV-1) were inoculated individually or as a three-virus cocktail onto donor surfaces (gloved fingertips or stainless steel) and either immediately interfaced with one or more recipient surfaces (fruit, gloves, or stainless steel) or allowed to dry before contact. Viruses on recipient surfaces were quantified by real-time quantitative reverse transcriptase PCR. Transfer rates were 58 to 60% for GII NoV from fingertips to stainless steel, blueberries, and grapes and 4% for raspberries under wet conditions. Dry transfer occurred at a much lower rate (<1%) for all recipient surfaces. Transfer rates ranged from 20 to 70% from fingertips to stainless steel or fruits for the GI, GII, and MNV-1 virus cocktail under wet conditions and from 4 to 12% for all viruses under dry transfer conditions. Fomite transfer (from stainless steel to fingertip and then to fruit) was lower for all viruses, ranging from 1 to 50% for wet transfer and 2 to 11% for dry transfer. Viruses transferred at higher rates under wet conditions than under dry conditions. The inoculum matrix affected the rate of virus transfer, but the majority of experiments resulted in no difference in the transfer rates for the three viruses. While transfer rates were often low, the amount of virus transferred to recipient surfaces often exceeded 4- or 5-log genomic copy numbers, indicating a potential food safety hazard. Quantitative data such as these are needed to model scenarios of produce contamination by food handling and devise appropriate interventions to manage risk.
人类诺如病毒（NoV）每年导致美国约 58%的食源性疾病。这些疫情大多数是由于食品处理人员受到污染。本研究的目的是量化污染的转移率和污染程度，即当用受诺如病毒污染的手处理小水果（蓝莓、葡萄和覆盆子）和食品接触表面（不锈钢）时，小水果和食品接触表面会发生污染。人类 NoV（基因组 I 和 II [GI 和 GII]）和鼠诺如病毒（MNV-1）单独或作为三种病毒鸡尾酒接种到供体表面（手套指尖或不锈钢）上，然后立即与一个或多个受体表面（水果、手套或不锈钢）接触，或在接触前让其干燥。通过实时定量逆转录 PCR 定量受体表面上的病毒。在潮湿条件下，从指尖到不锈钢、蓝莓和葡萄的 GII NoV 的转移率为 58%至 60%，而覆盆子的转移率为 4%。在所有受体表面，干燥转移的转移率均低于 1%。在潮湿条件下，从指尖到不锈钢或水果的 GI、GII 和 MNV-1 病毒鸡尾酒的转移率为 20%至 70%，在干燥转移条件下，所有病毒的转移率为 4%至 12%。在所有病毒中，从不锈钢到指尖再到水果的载体转移（载体转移）较低，在潮湿条件下转移率为 1%至 50%，在干燥条件下转移率为 2%至 11%。病毒在潮湿条件下的转移率高于干燥条件下的转移率。接种物基质会影响病毒的转移率，但大多数实验结果表明，三种病毒的转移率没有差异。虽然转移率通常较低，但转移到受体表面的病毒量通常超过 4 或 5 个对数基因组拷贝数，表明存在潜在的食品安全危害。需要定量数据来模拟食品处理人员污染农产品的情况，并制定适当的干预措施来管理风险。
