Quantitative PCR-based identification of enteric viruses contaminating fresh produce and surface water used for irrigation in Egypt

Fresh produce irrigated with surface water that may contain pathogens such as enteric viruses can lead to outbreaks of foodborne viral illnesses. In the current study, we performed real-time PCR (qPCR) to monitor the presence of enteric viruses such as human adenoviruses (HAdVs), hepatitis A virus (HAV), rotavirus group A (RVA), and norovirus GI (NoV GI) in surface water and fresh produce that were grown using this surface water in Egypt. Samples were collected on four occasions from different sites located in the Delta and in Greater Cairo, Egypt. Of the 32 water samples and 128 fresh produce samples, 27/32 (84.3%) and 99/128 (77.3%), respectively, were positive for at least one virus. HAdV (30/32) with a mean viral load = 1.5 × 10⁷ genome copies/L (GC/L) was the most commonly detected virus in water, followed by RVA (16/32, with a mean viral load = 2.7 × 10⁵ GC/L), HAV (11/32, with a mean viral load = 1.2 × 10⁴ GC /L), and NoV GI (10/32, with a mean viral load = 3.5 × 10³ GC/L). Additionally, HAdV (71/128, with a mean viral load = 9.8 × 10⁵ GC/g) was also the most commonly detected virus in the fresh produce, followed by NoV GI (43/128, with a mean viral load = 4.5 × 10³ GC/g), HAV (33/128, with a mean viral load = 6.4 × 10³ GC/g), and RVA (25/128, with a mean viral load = 1.5 × 10⁴ GC/g). Our results indicate that fresh produce may be contaminated with a wide range of enteric viruses, and these viruses may originate from virus-contaminated irrigation water. Moreover, this fresh produce may serve as a potential vector for the transmission of viral foodborne illnesses. These findings are important for future risk assessment analysis related to water/foodborne viruses. Graphical abstract . Please provide caption for Graphical AbstractGraphical abstract showing sample collection and processing