Physiochemical and Microbiological Quality of Lightly Processed Salmon (Salmo salar L.) Stored Under Modified Atmosphere.

Low-temperature cooking, such as sous vide, has become a favored method for processing seafood. For this method to be applicable for retail products, combinations with other processing steps are needed to keep the products safe and durable while maintaining high quality. The present experiments were designed to investigate the influence of low-temperature treatment (40, 50, or 60 °C) in combination with various packaging technologies (modified atmosphere [MA] or soluble gas stabilization [SGS]) on both the microbial growth and the physiochemical quality. Salmon loins were either kept natural or inoculated with Listeria innocua prior to drying (16 to 18 hr) in either 100% CO2 (SGS) or atmospheric air (MA packaging). All samples were sous vide treated, repackaged in MA, and stored at 4 °C for 24 days. The results showed shelf life to be significantly improved with the implementation of SGS, by prolonging the lag-phase and slowing the growth rate of both naturally occurring and inoculated bacteria. Variations in packaging technology did not significantly influence any of the tested quality parameters, including drip loss, surface color, and texture. Growing consumer demand for lightly processed seafood products makes Listeria spp. an increasing problem. The present experiment, however, has shown that it is possible to lower processing temperatures to as little as 40 or 50 °C and still obtain inhibition of Listeria, but with improved chemical quality compared to traditional processing.