The Effects of Modified Atmosphere Packaging on the Microbiological Properties of Fresh Common Carp (Cyprinus carpio L.)

The aim of this study was to compare the growth rate of total viable counts (TVC), psychrotrophic viable counts (PVC), coliform bacteria and E. coli in portions of fresh common carp (Cyprinus carpio L.) under two different modified atmosphere packaging (experimental MAP1: 70% N-2/30% CO2; experimental MAP2: 80% O-2/20% CO2) and air (control samples) stored at +4 +/- 0.5 degrees C, and to determine their shelf life. The presence of pathogens (Salmonella spp. and Listeria monocytogenes) was also surveyed in this study. A total of 360 portions from 90 common carp were examined. Laboratory analyses were performed on storage day 0 (production day) and days 3, 7 and 10. As compared to air packaging, the numbers of TVC and PVC were significantly lower (p < 0.001) in both modified atmosphere packaging (MAP) on storage days 7 and 10; coliform bacteria were significantly lower only on day 7. E. coli counts in fresh carp during storage were generally low, showing levels of < 1 log cfu/g. Salmonella spp. and Listeria monocytogenes were not detected in any of the examined samples. All the strains of Listeria spp. were identified as Listeria innocua. According to TVC values and sensory changes, the shelf life of carp portions was determined as 6 days in MAP1, 8 days in MAP2 and 3 days in air.