Enteric virus presence in green vegetables and associated irrigation waters in a rural area from Argentina. A quantitative microbial risk assessment

The aim of this study was to assess the presence of norovirus, rotavirus and infective enterovirus in leafy green vegetables and irrigation waters collected from a farm located at the province of C ' ordoba, Argentina, and to estimate the quantitative risk of infection by consuming these vegetables. During June 2014-July 2015, vegetables (n = 101) and their corresponding irrigation waters (n = 24) were collected. Viruses were concentrated in both matrices by polyethylene glycol precipitation and then were subjected to RT-PCR to assess the presence of norovirus and rotavirus. The concentrates were also inoculated in CaCo-2 cells to monitor the occurrence of infective enterovirus. The frequency of detection of norovirus, rotavirus and infective enterovirus in irrigation waters was 37.5%, 20.8% and 37.5% and in crops 60.4%, 22.7% and 35.6% respectively. Similar profiles of norovirus genogroups and rotavirus G-types distribution were observed in green vegetables and irrigation waters. The estimated risk of rotavirus infection associated with raw consumption of the vegetables harvested in that rural farm was 0.2 per person per day. This study demonstrates a wide distribution of human pathogenic viruses in irrigation waters and green leafy vegetables, which is of concern when, as in this case, the vegetables are eaten raw.