Resumo

Pre-cooked mussel (Perna perna) flesh is a perishable foodstuff that presents a limited shelf life which is attributed to a variety of microbial and physical-chemical degradation mechanisms. The preservation of the mussel flesh depends largely on raw product microbiota and process conditions, such as temperature, cross contamination, and storage conditions. Shelf life can be extended by the use of preservatives such as organic acids and salts, and through thermal treatment. Accordingly, the aim of this study was to analyze the thermochemical (brine and moderate heat) process effect on shelf life of vacuum-packed mussels flesh based on growth of microorganisms during storage at 10 ºC. Pre-cooked mussel flesh was packed in acidic brine (2 % NaCl and 1 % acetic acid) with a ratio of 60:40 w/w and the pouches were vacuum sealed. One batch was pasteurized at 65 ºC for 5 minutes and stored at 10 ºC. For comparison, another batch was stored at the same temperature without heat treatment. The microbiological analysis comprised of the psychrophiles, psychrotrophic, total viable count (TVC) and acid lactic bacteria. Among the microbiological analysis realized, the TVC value represented the highest impact on the microbiological quality of the product. The initial TVC of the untreated sample was 9.4 x 10℘3 cfu/g. Immediately after the heat treatment, the TVC was of 1.7 x 10℘2 cfu/g showing a TVC reduction. The shelf life of brined non-pasteurized sample was increased when compared to the literature data reported for untreated mussels flesh. In addition, the shelf life of thermochemical treated sample was significantly larger than earlier ones. The proposed thermochemical treatment on the vacuum-packed mussel flesh leads to an extension of the product’ shelf life, which results of practical interest for commercialization strategies.