LAUSR

Abstract Vibrio vulnificus and Vibrio parahaemolyticus are halophilic bacteria and can cause illness associated with the consumption of oysters. In this study, we tested the hypothesis to see if the adjustment of the acceleration voltage can change the efficacy of X-ray doses on V. vulnificus and V. parahaemolyticus in pure culture and inoculated V. parahaemolyticus within farm-raised live oysters (Crassostrea virginica). By using a tailor-made X-ray irradiator (Kimtron 350), the acceleration voltage was adjusted to 50, 200 or 350 kV and irradiated on pure culture of V. vulnificus or V. parahaemolyticus and farm-raised live oysters accumulated with a three-strain mixture of V. parahaemolyticus. Inactivation of V. vulnificus and V. parahaemolyticus pure cultures without filter had a lower inactivation when compared with filtered X-ray. With a 1 mm aluminum filter, 250–300 Gy X-ray reduced more than 6 log CFU ml−1 at 350 kV acceleration voltage. When 350 kV X-ray was applied on live oysters with the aluminum filter, 6 log MPN g−1 reduction of V. parahaemolyticus was achieved with 1250 Gy. The V. parahaemolyticus was significantly (p