Soluble Gas Stabilisation Technology to Control Listeria Innocua and Improve Microbiological Stability in Ready-to-eat Vacuum-Packed Salmon During Cold Storage and Temperature Abuse

Ready-to-eat (RTE) salmon products face persistent safety challenges from Listeria monocytogenes, limiting shelf life and contributing to food waste. Soluble gas stabilisation (SGS) technology, which dissolves CO2 into the salmon muscle before packaging, may offer an additional hurdle to enhance microbial safety. This study investigated the effect of SGS pretreatment on the growth of Listeria innocua (CCUG 15531, used as a surrogate for L. monocytogenes) and the natural microbiota of vacuum-packed RTE salmon stored at 4 °C and 8 °C. Salmon portions were pretreated with pure CO2 (SGS) or air (CTRL) for 18.5 h, at 4 °C. SGS pretreatment significantly inhibited the growth of L. innocua, total aerobic bacteria, psychrotrophic bacteria and H2S-producing bacteria across both storage temperatures. Complete inhibition of L. innocua was observed for up to 30 days at 4 °C. SGS pretreatment also led to reduced microbial diversity; however, Photobacterium spp. remained dominant. Freshness and spoilage indicators (K value, H value, and biogenic amines) were mainly influenced by storage temperature and time, with SGS pretreatment mainly delaying freshness loss at 4 °C. Overall, SGS pretreatment represents a promising strategy for controlling Listeria in RTE salmon, with robust effects maintained even under minor temperature abuse conditions.