CHANGES IN PROXIMATE COMPOSITION AND MICROBIAL QUALITY OF CLUB MACKEREL (Scomber japonicus) UNDER LOCAL MARKET CONDITIONS IN ADO-EKITI, NIGERIA

Abstract

The present study evaluated changes occurring in the proximate composition and microbial quality of Club Mackerel (Scomber japonicus) that were displayed for sale under local market conditions in Ado Ekiti, Nigeria. Fish were collected from the market, firstly at the time they were removed from the carton in the morning (0 hour), and subsequently from those displayed for sale at four hour intervals (4, 8 and 12 hours). Proximate and microbial analyses of collected fish samples were done in the laboratory following standard procedures. The results revealed that protein contents of the fish were significantly (P<0.05) reduced at the 12 hour than at 0 hour of sampling, while the moisture contents were significantly higher at the 12 hour than at 0 hour of sampling. Significant differences were not observed in the values for crude fat and ash contents at all sampling times. In terms of microbial quality, both Salmonella and Fungi were not detected at all sampling times. Fish samples at 12 hours had significantly (P<0.05) highest total bacterial and Staphylococci counts than samples collected at 0, 4 and 8 hours, while significant differences were not observed in both Coliform and E. coli counts. The present study therefore revealed remarkable loss in quality in terms of protein contents and increased total bacterial and Staphylococci counts after 12 hours of thawing and displaying Club Mackerel (S. japonicus) in open markets.