MICROBIAL QUALITY OF IMPORTED FROZEN Sardinella species AND Micromesistius poutassou OFFERED FOR SALE IN OYO STATE, NIGERIA

Olaolu O Fawole ,O.a Oyelese

doi:10.7176/fsqm/85-08

Abstract

Microbial quality of frozen fish offered for sale in Oyo state markets was investigated. The four Agricultural Development Programme (ADP) zones of the state were used for the study. Sardinella species and Micromesistius poutassou were selected among the commercially important imported frozen fish species in the state based on their availability in all zones. Bacterial and Fungal counts were determined using standard procedures. Data were analysed using descriptive statistics, percentages and t-test. Ten bacteria and three fungi and three yeast species were isolated from the fishes evaluated. Predominant bacteria isolates were Shewanella putrefaciens and Streptococcus faecium , fungi included Penicillium notatum and Aspergillus niger while yeast were Cryptococccus laurentii and Torulaspora debrueckii . Total viable counts for bacterial and fungal counts were 3.1x10 5 cfu/g and 1.8x10 5 cfu/g, respectively for Sardinella spp. and 3.2x10 5 cfu/g and 2.4x10 5 cfu/g for M. poutassou . Although all the fish samples were within acceptable limit, the number of bacteria isolated showed that the quality of frozen fish did not reach expected standard in Oyo state. Keywords: Microbial quality; Frozen fish; Bacteria count; Fungi count, ADP zones DOI : 10.7176/FSQM/85-08 Publication date :March 31 st 2019

Highlights

One-fourth of the world’s food supply and 30% of landed fish are lost through microbial activities alone (Huis in’t Veld, 1996 and Amos, 2007)
The Total Bacteria Count of imported frozen fish across the four zones of the study area as shown in Table 1 indicates that the highest Total Viable Count (3.1 x105 cfu/g) was from Ogbomoso zone in Sardinella spp. fish samples, while the lowest was from Oyo zone (1.2 x105cfu/g)
Total Lactic Acid Bacteria Count (TLAB) in Sardinella species was lower in Ibadan/Ibarapa, Ogbomoso and Saki zones than in M. poutasssou

Summary

Introduction

One-fourth of the world’s food supply and 30% of landed fish are lost through microbial activities alone (Huis in’t Veld, 1996 and Amos, 2007). Frozen fish displays third order biotic activity. It belongs to the class of foods in which the respiration process is suspended, but in which biochemical, microbial and other decomposition processes which must be taken into account still proceed (Huss et al, 1992). Bacteria according to Eyo (2001) secrete digestive juices and enzymes which breakdown the tissue and cause spoilage of fish. This results in loss of flavour and odour and is replaced by a sour and stale odour. Fish may harbor a number of biohazards as well as chemical contaminations such as biogenic amines, biotoxins, pathogenic bacteria and viruses if not properly handled (Ashie et al, 1996 and Gram et al, 2000)

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Discussion

Conclusion