Method validation for norovirus detection in naturally contaminated irrigation water and fresh produce

Human enteric viruses are shed in extremely high numbers in the feces of infected individuals, becoming environmental contaminants and eventually leading to contamination of a variety of foodstuffs at the pre-harvest stage. Among these foods at risk is fresh produce and irrigation water is a major vehicle for crop contamination. In the present study, a standardized molecular method for quantitative virus assay has been evaluated in different types of fresh produce and in irrigation water for human norovirus (NoV) detection. Two different virus concentration procedures, polyethylene-glycol precipitation (PEG) and organic flocculation (OF), were employed. The procedures were initially assayed in spiked samples and later validated on naturally contaminated samples from the Nile Delta in Egypt.