Microbiological spoilage and volatiles production of gutted European sea bass stored under air and commercial modified atmosphere package at 2 °C

Microbiological, sensory, TVB-N and TMA-N changes and Volatile Organic Compounds (VOCs) detection using the SPME/GC–MS technique, were performed to evaluate potential chemical spoilage indices (CSI) of gutted sea bass (Dicentrarchus labrax) stored at 2 °C under air and in modified atmosphere packaging (MAP CO2: 60%, O2: 10%, N2: 30%). Shelf-life, determined by sensory evaluation, of gutted sea bass stored at 2 °C under air and MAP was 9 and 13 d respectively. Pseudomonas and H2S producing bacteria were among the dominant spoilage microorganisms under both storage conditions, while Lactic Acid Bacteria (LAB) and Brochothrix thermosphacta were co-dominant with Pseudomonas and H2S producing bacteria under MAP. The traditional CSIs such as TVB-N and TMA-N were increased substantially only at the late stages of storage or after rejection of the products, making them unsuitable for freshness/spoilage monitoring throughout storage. A substantial number of VOCs attributed to microbiological action or chemical activity, were detected including alcohols, aldehydes, ketones, organic acids and esters. The level of microbial origin VOCs such as ethanol, 2-ethyl-1-hexanol, 3-methyl-1-butanol, 2-methyl-1-butanol, 3-methylbutanal, 2-methylbutanal and some ethyl esters increased during storage, suggesting their potential as CSIs. •Microbiological spoilage analysis of gutted European sea bass was performed.•Volatile compounds profile was determined during spoilage of gutted sea bass.•Storage conditions affected shelf-life, spoilage microbiota and volatile profile.•TVB-N and TMA-N proved non-suitable for chemical spoilage indices.•Various microbial origin volatiles confirmed as potential chemical spoilage indices.