Disinfection of Salmonella spp. on Tomato Surface by Pulsed Ultraviolet Light and Selected Sanitizers

Abstract

The efficacy of three sanitizers (10 mL/L peracetic acid, 10 mL/L hydrogen peroxide and 20 mL/L commercial GRAS disinfectant) for inactivating Salmonella spp. inoculated onto the surface of whole tomatoes stored up to 8 days was investigated when they were used alone or in combination with pulsed ultraviolet light (PUV). Ten mL/L peracetic acid alone resulted in an average 3 log10 reductions throughout the 8-day storage. Ten mL/L hydrogen peroxide and 20 mL/L commercial biodegradable GRAS sanitizer alone yielded 1.41 and 1.29 log10 reductions, respectively, on day 0, but from day 2 to day 8 of storage, their disinfecting effect dwindled, with no significant difference detected from control (water rinse) on day 8 (p ≤ 0.05). The 60s PUV treatments alone achieved less than 2 log10 reductions, but when it was combined with 10 mL/L hydrogen peroxide, the bacterial reduction significantly increased to over 4 log10 during the 8-day storage (p ≤ 0.05). Similarly, PUV also enabled 20 mL/L commercial GRAS sanitizer to have unchanged bactericidal effect throughout the 8-day storage period. Results from this study showed that sanitizers combined with PUV radiation could generate a significant and lasting inactivation of Salmonella spp. on the surface of tomatoes.