Significance and molecular detection of noroviruses in fresh produce

Human noroviruses (HuNoVs) are a primary cause of epidemic and sporadic cases of non-bacterial gastroenteritis; easily transmitted by the fecal-oral route which involves food as a frequent vehicle causing HuNoVs to be the major agent of food-borne illness worldwide. Primary factors contributing to the food contamination are contacts with infected food handler, cross-contamination during preparation, contaminated raw product and insufficient heating. Fresh produce are typically eaten raw with no thermal processing, therefore they are considered as high risk food because contamination can occur at the pre-harvest stage due to faecally polluted irrigation water and possible internalization; during harvest/postharvest stage and at the point of sale/consumption due to contact with human faeces/faecally soiled materials and infected food handlers; cross-contamination from polluted working equipment/surfaces. Detection of food-borne HuNoVs in fruits and vegetables has become important based on the increasing number of reported outbreaks. Real-time RT-PCR is considered the gold standard detection method due to its high sensitivity and specificity, as well as for possibility of quantification and multiplexing.