Shelf-Life Evaluation of Sliced Cold-Smoked Rainbow Trout (Oncorhynchus mykiss) Under Vacuum (Pv) and Modified Atmosphere Packaging (MAP)

Cold smoked trout (Oncorhynchus mykiss) is a traditional product from the San Daniele del Friuli area (Italy), usually packaged under vacuum, and its shelf life is 60 days. Aim of this study was to evaluate the influence of two different packaging systems (Vacuum packaging-VP and Modified atmosphere packaging-MAP) on the microbial, physico-chemical and sensorial changes of sliced cold smoked rainbow trout during storage. MAP packaged sample showed lower microbial loads than VP packaged sample throughout storage. Microbial count of VP packaged sample exceeded the limit of 6 log CFU/g after 60 days of storage. The total volatile base-nitrogen (TVB-N) values increased over time in both treatments, reaching values close to the limit of 40 mg N/100 g after 45 days. Also TBARS values did not were up to 10 nmol/g in both VP and MAP. The shelf life of 60 days seems to be too long, particularly for the VP samples. A panel composed of 12 nonprofessional assessors perceived significant differences in the sensorial characteristic of the samples, and concluded that the sensorial quality of MAP packaged products were better than the VP ones (P<0.05).