Quantificação das bactérias heterotróficas: mesófilas, psicrotróficas e psicrófilas da captura à deteriorização da tilápia do nilo (Oreochromis niloticus)

Abstract

Fish is a susceptible deterioration food, being necessary the determination of spoilage bacterial groups. Thus, the objective was to quantify mesophilic ,psychrotrophic, and psichrophilic bacteria in Nile tilapia (Oreochromis niloticus) during storage at refrigeration temperatures (± 4 ° C) until its complete deterioration. Three experiments, each eight (8) samples of tilapia newly captured and stored in refrigerators at temperature of ± 4 ° C, with daily, a sample taken for microbiological and sensory analysis. Sensory analysis was adopted for the evaluation table of Tony Research Station (UK) adapted for Nile tilapia. We evaluated the criteria for appearance, texture and smell of fish, according to the summation of sensory characters (S.S.C.) and were classified as excellent (20-18), good (17-14), regular (13-10), early spoilage (9-6) and spoilage (<6). From each specimen, were quantified mesophilic ,psychrotrophic, and psichrophilic by pour plate technique. There was no correlation between bacterial groups analyzed and the S.S.C. the a = 5%. The fish is considered unsafe for consumption from the 5th day of storage. Among the variables analyzed, which further contributed to the deterioration was the texture. It is suggested therefore that the storage of Nile tilapia (Oreochromis niloticus) is not eviscerated and stored in the refrigerator at ± 4°C does not exceed 5 days.