Spoilage indicator bacteria in farmed Atlantic salmon (Salmo salar) stored on ice for 10 days

This study investigated the growth of indicator and spoilage bacteria on whole Atlantic salmon (Salmo salar) stored aerobically at 2 degrees C. On days 0, 2, 3, 6, 8 and 10 microbiological analysis was carried out on inner flesh and outer skin samples as well as outer skin swabs (25 cm(2) surface areas). Mesophilic total viable counts (TVCm) on skin, flesh and swab samples increased from 1.9, 1.1 and 2.7 log(10) CFUcm(2) to 6.0, 5.1 and 5.7 log(10) CFU/cm(2) after 10 days, respectively. Psychrotrophic counts (TVCp), increased from 2.2, 1.8 and 3.1 log(10) CFU/cm(2) to 6.2, 5.3 and 5.9 log(10) CFU/cm(2), for skin, flesh and swab samples respectively. Hydrogen sulphide producing bacteria (HSPB), lactic acid bacteria (LAB), Pseudomonas spp., Brochothrix thermosphacta and Photobacterium spp. grew well with similar growth rates (mean generation times of 17.2-26 h). It was concluded that the shelf-life of salmon at 2 degrees C was approximately 10 days and that HSPB, LAB, Pseudomonas spp., Br. thermosphacta and Photobacterium spp. may be a better indicator of fish spoilage rather than TVC growth, with a count of 5-6 log(10) CFU/cm(2) indicating the end of shelf-life.