Survival behaviour of Salmonella enterica in fish and shrimp at different conditions of storage

Abstract Seafood contamination with Salmonella enterica is a public health concern. The objective of this study was to investigate the survivability of Salmonella enterica serotype Typhimurium in fish and shrimp subjected to chilled (1 ± 2 °C) and frozen storage (−18 ± 2 °C). Bombay duck fish (Harpadon nehereus) and shrimp (Parapenaeopsis stylifera) were surface inoculated with 8 and 4 log CFU/g levels of S. Typhimurium. Survivability was studied by surface plating method on Salmonella-specific selective agar at regular intervals. In fish and shrimp inoculated with 8 log CFU/g and stored at −18 °C, viable counts could be detected for up to 90 days. At lower inoculation level of 4 log CFU/g, Salmonella was viable up to 60 days in frozen fish, while in frozen shrimp the bacterium could survive for only 15 days. In fish and shrimp stored in ice for 15 days, Salmonella showed 1–2 log CFU/g reduction in counts irrespective of initial inoculation levels. The results of this study suggest that the survival behaviour of Salmonella is influenced by the seafood matrix, temperature of storage and the population density of the bacterium itself. Therefore, strict monitoring of handling and storage procedures is necessary to control the processes that foster the survival and multiplication of Salmonella in the seafood chain.