Hyperbaric Storage of Vacuum-Packaged Fresh Atlantic Salmon (Salmo salar) Loins by Evaluation of Spoilage Microbiota and Inoculated Surrogate-Pathogenic Microorganisms

Abstract

Hyperbaric storage at low and room temperature (HS/LT, 60 MPa/10°C; HS/RT, 75 MPa/25°C; 30 days) of vacuum-packaged Atlantic salmon (Salmo salar) was studied and compared with storage under atmospheric pressure (AP, at 5, 10, and 25°C). Spoilage and inoculated surrogate-pathogenic (Bacillus subtilis endospores, Escherichia coli, and Listeria innocua) microorganisms were monitored during storage. Under AP, the spoilage microorganisms increased during storage time, reaching total aerobic mesophiles values higher than the acceptable limit after 15 and 5 days at AP/5°C and AP/10–25°C, respectively. Contrarily, both HS conditions inhibited and inactivated the spoilage microorganisms, reaching total aerobic mesophiles to values below the detection limit after 30 days under HS/RT. Under AP, surrogate-pathogenic microorganism counts increased, while for both HS samples B. subtilis endospores reached counts below the detection limit after 30 days while E. coli and L. innocua counts were also reduced. In conclusion, HS decreased initial population of spoilage and inoculated surrogate-pathogenic microorganisms, showing that besides the shelf-life extension (due to microbial growth inhibition), it also increased microbial safety (by microbial inactivation) of vacuum-packaged Atlantic salmon.