Validation of NIRS analysis in Authentication of Fresh and Frozen-ThawedFish Products

Providing label information about the preserving method used for fish conservation (eg. chilling or freezing) could have a strong influences on consumer acceptance. Thawed fish is more susceptible to microbial invasion than fresh fish, with a consequent reduction of its shelf life1. This should be strongly considered on management plans, such as the HACCP (Hazard Analysis and Critical Control Point) system, to reach higher standards of seafood quality and safety. The substitution of thawed products labeled as fresh is a common commercial fraud. There are numerous techniques available to distinguish fresh-chilled from frozen-thawed fish, having different performances. This study was the first part of a collaborative trial among different laboratories. The ring trial was carried out to evaluate the discriminating ability of three analytical techniques, a histological method, front-face fluorescence spectroscopy and infrared spectroscopy (IRs). This paper only reports the performances of IRs techniques, in terms of their specificity, sensitivity, accuracy, intra-laboratory reproducibility and agreement with the Standard test for authentication of fresh and thawed Gilthead Sea bream (Sparus aurata) fillets.