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.

Abstract

BACKGROUNDThe purpose of the present study was to examine the inactivation of Salmonella enterica (50 μL; 109 CFU g−1), Listeria monocytogenes (50 μL; 109 CFU g−1), and murine norovirus (MNV‐1; 50 μL; 107 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 °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.RESULTSWhen 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 °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.CONCLUSIONThe 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. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.