Controlling Listeria monocytogenes in Cold Smoked Salmon with the Antimicrobial Peptide Salmine

Listeria monocytogenes (LM) is a major safety concern for smoked salmon producers, as it can survive both the brining and smoking process in cold smoked salmon production. Salmine is a cationic antimicrobial peptide derived from the milt of salmon that has been shown to inhibit the growth of LM in vitro. Commercialization of this peptide would add value to a waste product produced when raising salmon. The purpose of this study was to determine the anti-listeria activity of salmine in smoked salmon by measuring the viable counts of LM over time. Cold smoked salmon was treated with a salmine solution or coated with agar or k-carrageenan films incorporating salmine to maintain a high surface concentration of the antimicrobial. Samples were then inoculated with approximately 1.0x10(3) cells of LM. The viable counts were then enumerated throughout 4 wk at 4 degrees C storage. It was found that 5 mg/g salmine delayed the growth of LM on smoked salmon. These samples had significantly (P<0.05) lower LM counts than on the untreated samples on days 13 and 22. Edible films did not significantly (P > 0.05) improve the antimicrobial efficacy of salmine. The peptide combined with biopolymers also had lower antimicrobial activity in vitro when compared to salmine alone. These results suggest there is potential for salmine to be used as a natural hurdle to inhibit growth of LM due to post process contamination; however, future investigations for extending this effect throughout the shelf life of smoked salmon products are warranted. Practical Application This research indicates that the antimicrobial peptide salmine can potentially be used as a natural antimicrobial compound to inhibit Listeria monocytogenes in cold smoked salmon. Commercialization of this peptide could improve the safety of this product, maintain a clean label, and add value to a waste product from salmon aquaculture.