Changes in the microbial communities of air-packaged and vacuum-packaged common carp (Cyprinus carpio) stored at 4 °C

The dominant microbiota of air-packaged (AP) and vacuum-packaged (VP) common carp fillets during storage were systematically identified. Culture-dependent methods were used for microbial enumeration and 16S rRNA genes of the isolated pure strains were sequenced and analyzed. Different packaging conditions affected the growth of microbiota and the shelf life of carp. Shelf-life of AP and VP fillets was 8 and 12 days, respectively. Vacuum packaging delayed the increase of biogenic amines levels compared to air packaging, especially for cadaverine and tyramine levels. In the present study, a total of 13 different genera comprised the microbial communities of fresh carp fillets and Acinetobacter dominated the indigenous flora of carp. However, variability in bacterial community composition was observed in these two packaging conditions. Pseudomonas were the only microbiota found in the spoiled AP carp, whereas Carnobacterium followed by Aeromonas were found mainly in VP samples. Other genera Shewanella, Lactococcus, and Pseudomonas were also found in low numbers at the end of the VP fillets' shelf life. Additional microbial enumeration observed the highest Pseudomonas counts (8.77 log CFU/g on day 8) in AP samples and a relatively high level of lactic acid bacteria (7.74 log CFU/g on day 12) in VP samples.