Contamination of fresh vegetables and berries with human enteric viruses is a major cause of food poisoning. The aim of this study was to investigate the prevalence of norovirus GI, norovirus GII, hepatitis A virus (HAV), adenovirus, astrovirus, rotavirus, and male-specific coliphage systematically in fresh fruit and vegetables and associated agricultural environmental samples, including irrigation water, soil, and worker's gloves. Enteric viruses were detected by international standard methods (ISO/TS 15216), and male-specific coliphages were isolated using US EPA Method 1601. For the study, 773 samples were collected from June 2016 to April 2017, including Chinese cabbage (n = 244), cucumber (n = 98), lettuce (n = 73), strawberry (n = 120), soil (n = 191), irrigation water (n = 14), and gloves (n = 27). Two cucumber and two irrigation water samples were positive for norovirus GI, and one cucumber and two irrigation water samples were positive for norovirus GII. HAV was detected in one strawberry sample and one glove sample. The other tested foodborne viruses were not detected in any of the samples. Sixteen male-specific coliphages were isolated from Chinese cabbage, cucumber, lettuce, cherry tomato, soil, and irrigation water. The isolation of male-specific coliphage would be more practical to investigate the fecal contamination in produce rather than pathogenic viruses.
Keywords: hepatitis A virus; norovirus; on-farm food safety; preharvest food safety; vegetables.