Effect of Traditional Marinating on Bacterial and Chemical Characteristics in Frozen Rainbow Trout Fillet

Background: in recent years, there has been an increasing interest in using food addi-tives from natural sources to improve taste and also extend shelf life of semi-preserved food. the aim of this paper was to examine chemical and microbiological changes pro-moted by a traditional marinating process in rainbow trout fillets during frozen storage.methods: fish fillets were immersed in traditional marinades and stored at -18 °c for 56 days. some chemical and microbial characteristics like total volatile basic nitrogen (tvn), thiobarbituric acid (tba), water holding capacity (whc), ph, mesophilic, and psychrophilic bacterial count were performed with 7 days interval. the results were analyzed by repeated measure anova test using spss v. 16.0 software.results: data showed that although the value of tvn, tba and, whc in marinated samples were higher than control ones, but the differences were not significant (p>0.05). the numbers of bacteria in marinated samples were lower than control groups and for psychrophilic bacteria was significant (p<0.05).conclusion: the most obvious finding to emerge from this study is that rainbow trout flesh could be marinated and stored at -18 ˚c for at least 56 days with no major unfavor-able changes.