Effect of vacuum and modified atmosphere packaging on the microbiological, chemical and sensory properties of tropical red drum (Sciaenops ocellatus) fillets stored at 4 °C

Aims: The effect of vacuum (VP - 4 degrees C) and CO2/N-2 atmosphere (MAP - 4 degrees C) packaging on the quality of red drum fillets compared with whole gutted iced fish was investigated. Methods and results: A metagenomic approach, bacterial enumeration and isolation, biochemical and sensory analyses were carried out. The organoleptic rejection of whole fish was observed at day 15 whereas VP and MAP fillets appeared unacceptable only after 29 days. At these dates, total mesophilic counts reached 10(7)-10(8) CFU g(-1). According to Illumina MiSeq sequencing, Arthrobacter, Chryseobacteriurn, Brevibacterium, Staphylococcus and Kocuria were the main genera of the fresh red drum fillets. At the sensory rejection time, lactic acid bacteria (LAB), particularly Carnobacteritan sp., dominated the microbiota of both types of packaging. The pH value of fresh samples was between 5.96 and 6.37 and did not vary greatly in all trials. Total volatile basic nitrogen (TVBN) and trimethylamine (TIVIA) concentrations were low and not represent reliable indicators of the spoilage, contrary to some biogenic amines (cadaverine, putrescine and tyramine). Conclusion: Chilled packed fillets of red drum have an extended shelf-life compared to whole gutted iced fish. Overall, few differences in sensory and microbial quality were observed between the VP and MAP samples. Significance and impact of the study: Next-Generation Sequencing (NGS) provided data on the microbiota of a tropical fish.