Evaluation of water-assisted UV-C light and its additive effect with peracetic acid for the inactivation of Listeria monocytogenes, Salmonella enterica and murine norovirus on whole and fresh-cut strawberries during shelf-life

BACKGROUND The purpose of the present study was to examine the inactivation of Salmonella enterica (50 mu L; 10(9) CFU g(-1)), Listeria monocytogenes (50 mu L; 10(9) CFU g(-1)), and murine norovirus (MNV-1; 50 mu L; 10(7) 50% tissue culture infectious dose (TCID50) mL(-1)) on whole and fresh-cut strawberries after 2 min disinfection treatments (water (H2O), chlorine 200 mg L-1 (NaClO), water-assisted ultraviolet-C (UV-C) (WUV), and the combination WUV and 40 mg L-1 of PA (WUV + PA)) in a water tank (15 L) equipped with 4 UV-C lamps (17.2 W each), and after 7 days of cold storage (4 and 10 degrees C). For MNV-1, dry UV-C treatment (DUV) was also tested. For all UV-C treatments, an irradiation dose of 1.3 kJ m(-2) was used. RESULTS When strawberries were washed with WUV, L. monocytogenes and S. enterica were reduced by 2.8 and 2.2 log CFU g(-1), respectively. The addition of 40 mg L-1 of PA to WUV (WUV + PA) increased the reduction range of L. monocytogenes and S. enterica by 1.9 and 0.8 log, respectively. Regarding the wash water, no pathogens were recovered after the WUV + PA treatment (detection limit 50 CFU mL(-1)). Depending on storage conditions (7 days at 4 or 10 degrees C), reductions observed were 0.5 to 2.0 log for S. enterica and 0.5 to 3.0 log for L. monocytogenes. The reductions in MNV-1 titer after disinfection treatments ranged from 1.3 to 1.7 log. No significant differences between storage conditions were observed for MNV-1: titers did not decline or were reduced up to 0.3 log after 7 days of cold storage. CONCLUSION The three-way action for disinfecting strawberries by UV-C irradiation and PA, plus the physical removal of the microorganisms by agitated water, are effective against foodborne pathogens on strawberries and water wash. During storage, WUV had a larger impact on the inactivation kinetics of S. enterica. Storage had little impact on MNV-1 inactivation. (c) 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.