Elimination of Vibrio parahaemolyticus biofilms on crab and shrimp surfaces using ultraviolet C irradiation coupled with sodium hypochlorite and slightly acidic electrolyzed water

Abstract

Vibrio parahaemolyticus is a biofilm-producing seafood-borne pathogen that causes gastrointestinal disease in humans. Therefore, our study aimed to assess the elimination effects (alone or in combination) of ultraviolet C (UV-C; 5-60 mW x s/cm(2)) irradiation, sodium hypochlorite (NaOCl; 50-300 ppm), and slightly acidic electrolyzed water (SAEW; 1-15 min) on V. parahaemolyticus biofilms on crab and shrimp surfaces. SAEW alone had more significant effects than NaOCl even though it contained lower free chlorine concentrations. The combined UV-C/NaOCl treatment exhibited a significant (P < 0.05) but low reduction of V. parahaemolyticus biofilms on shrimp and crab surfaces, whereas UV-C/SAEW acquired a significantly higher (P < 0.05) reduction on both surfaces. 60 mW x s/cm(2) UV-C coupled with 300 ppm NaOCl rendered maximum reductions of 3.78 and 3.32 log CFU/cm(2) on shrimp and crab surfaces, respectively, whereas 60 mW x s/cm(2) UV-C and 15 min of SAEW resulted in 4.41 and 4.06 log CFU/cm(2) reductions in shrimp and crab, respectively. Therefore, our findings indicate that both UV-C/NaOCl and UV-C/SAEW treatment could be employed to improve the microbiological safety of the seafood industry.