Peracetic Acid Sanitation on Arugula Microgreens Contaminated with Surface-Attached and Internalized Tulane Virus and Rotavirus

Hydroponic production of vegetables is becoming more common, especially in regions with unfavorable climate for year-round crop production. However, if viruses are present in the hydroponics feed water, then there is a chance that infectious viruses will be internalized into the tissues of hydroponically grown vegetables. When this happens, surface sanitization of postharvest vegetables may not be effective because the sanitizer cannot disinfect the internalized viruses. In this study, we determined if the effectiveness of peracetic acid (PAA), a sanitizer used in the vegetable industry, is affected by the location of viruses (produce surface or interior tissue) in microgreen arugula. Either internally or externally contaminated hydroponically grown microgreen arugula was then treated with PAA at either 30 or 80 ppm for up to 3 min. The PAA disinfection efficacy was higher when the RV was on the arugula surface (approximately 5-log₁₀ in PFU after 3 min of exposure), instead of the arugula interior (1.5-log₁₀ in PFU after 3 min of exposure). However, PAA disinfection efficacy of TV was not dependent on the virus location in arugula. For both internalized TV and RV, the disinfection efficacy was less than 2-log₁₀ in PFU using all the tested PAA concentrations and exposure times examined here. Thus, both the type and location of virus in fresh vegetables may influence the virus disinfection of postharvest vegetables. Therefore, the optimization of sanitation for postharvest fresh vegetables is needed to reduce foodborne viral infection risks.