Efficacy of Gamma Irradiation in Eliminating Salmonella typhimurium Contamination in Seafood

Abstract

Salmonella is a foodborne pathogen known to cause gastrointestinal disturbances. Contamination of seafood with Salmonella is a major public health concern, often occurring through cross-contamination. The natural habitat of Salmonella is the gastrointestinal tract of animals, including birds and humans. The current research study was carried out to investigate the gamma radiation sensitivity of Salmonella Typhimurium (NCIM 2501) in shrimp, squid, and clam samples. The decimal reduction dose (D10) values of Salmonella Typhimurium in saline and nutrient broth were 0.119 ± 0.004 kGy and 0.139 ± 0.0014 kGy, respectively. Seafood samples such as shrimp, squid, and clams were inoculated with Salmonella Typhimurium and exposed to gamma irradiation at doses of 0, 0.1, 0.2, 0.3, and 0.4 kGy to evaluate the effectiveness of irradiation in the complete elimination of Salmonella Typhimurium. The D10 values of Salmonella Typhimurium in shrimp, squid, and clam samples were found to be 0.182 ± 0.0007 kGy, 0.209 ± 0.0014 kGy, and 0.192 ± 0.004 kGy, respectively. Gamma radiation treatment at a dose of 5 kGy resulted in the complete reduction of 6.85 × 10⁸ CFU/g of Salmonella Typhimurium from shrimp, squid, and clam samples. Additionally, no recovery of Salmonella Typhimurium was observed in 5 kGy-treated shrimp, squid, and clam samples stored at 4°C for up to 12 days, even after enrichment and selective plating. The results of the study reveal that application of gamma irradiation is very effective to control Salmonella contamination in seafood without affecting sensory quality and ensures seafood safety.