An evaluation of fish freshness: a proposal for a new index

The purpose of this study is to define a new system for assessing the freshness of marine bony fish based on measurable parameters. 151 fish were analysed to determine the concentrations of total volatile basic nitrogen, trimethylamine N-oxide, trimethylamine and malondialdehyde. The results of the determinations were included in an algorithm to calculate the value of the Freshness Index (FI). The most appropriate threshold value of FI that can distinguish fresh from not fresh fish was 0.33 (sensitivity 95.6%, specificity 73.6%). The results demonstrate the possibility of using the index for the evaluation, at low-cost, of consignments of fresh or presumed fresh fish both in the phase of official control and in self-verification systems. --Keywords: freshness index, fish, Malondialdehyde, Total Volatile Basic Nitrogen, Trimethylamine, Trimethylamine N-Oxide--