Screening the effect of ionizing radiation on microbiological quality, sensory acceptability and shelf life extension of lean fish fillets

Abstract

Stripped weakfish (Cynoscion guatucupa) fillets were packed and irradiated at 0, 1.5, 4, and 6.5 kGy. The behavior of total mesophilic and psychrotrophic aerobic bacteria, total and fecal coliforms, and Staphylococcus spp. was analyzed during 33 days at 4 ± 1 °C. Proximate chemical composition, pH, and total volatile basic nitrogen (TVBN) were determined. Sensory acceptability of cooked fillets was evaluated based on the aroma, appearance, mouthfeel, taste, and global acceptability. Gamma radiation reduced the counts of the studied microorganisms in a dose-dependent manner. pH and TVBN behavior corresponded with microbiological counts during storage. All sample´s attributes were well accepted, with average scores around 7 on a 9-point hedonic scale, and no differences were observed due to radiation treatment on day 1. Control sensory acceptability decreased on day 5, while 4 and 6.5 kGy samples were accepted after 33 days, to the same extent as on day 1. A dose of 4 kGy extended this fresh product shelf life by 16 days at 4 ± 1 °C, maintaining its sensory quality. Gamma radiation reduced initial microorganism counts, slowed their growth, and decreased TVBN production. It maintained the sensory acceptability during storage by slowing the rate of deterioration-associated changes. Radiation extended the shelf life under refrigeration, adding value to the product while maintaining its fresh condition.