Growth control of Listeria innocua 2030c during processing and storage of cold-smoked salmon-trout by Carnobacterium divergens V41 culture and supernatant

Abstract

The objectives of this study were to ascertain the efficacies of Carnobacterium divergens V41 and its supernatant V41 as treatments to control Listeria innocua 2030c during salmon-trout (Oncorhynchus mykiss) cold-smoking processes by treating the raw fish fillets. Fillets were dip-inoculated with 2% (v/v) culture of L. innocua 2030c and/or 2% (v/v) culture of C. divergens V41 culture and 2% or 5% (v/v) of culture supernatant V41. Fillets were dry-salted for 6 h and an average salt content of 5.3% (water phase salt) was obtained. Salted fillets were cold-smoked for 5 h (3 h of drying + 2 h of smoking) and stored at 5 °C for 3 weeks in vacuum packs. The % of salt in the water phase was determined for all fillets. Sensorial analyses were performed in order to compare treated/untreated cold-smoked salmon-trout fillets to ascertain potential spoilage odours due to the treatments. All the treatments with C. divergens V41 or supernatant showed a significant inhibitory effect on L. innocua 2030c growth, but the 5% (v/v) C. divergens supernatant treatment, was by far the most effective against this species. No significant off-odours were found in the products with respect to the tested treatments.