Quality index method (QIM) and quantitative descriptive analysis (QDA) of Nile tilapia (Oreochromis niloticus) quality indices

Abstract

The aim of this study was to develop specific criteria for evaluating freshness in farmed Nile tilapia (Oreochromis niloticus), eviscerated and stored on ice, by employing sensorial, physicochemical and bacteriological analyses. Sensorial analyses were composed of quantitative descriptive analysis (QDA) for cooked fish and quality index method (QIM) for raw fish evaluation in samples stored for 22 days. Psychrotrophic aerobic heterotrophic bacteria were counted in muscles with and without skin stored for 28 days. Total volatile bases (TVB) were also determined in samples stored for 22 days. TVB analyses were within legal limits during the 22 days. Although psychrotrophic countings remained within acceptable limits until 18 days of storage, increased intensity in the perception of undesired alterations was observed on the 15th day of storage in the Nile tilapia as evaluated by QDA and by QIM. Based on the results of this trial, a shelf-life of 15 days is suggested for farmed tilapia, eviscerated and stored in ice.