Bacterial Contamination of Some Edible Shellfish Harvested from Kalarugbani Creek, Rivers State, Nigeria

Abstract

The bacteriological quality of raw shucked oyster (RSO), raw extracted periwinkle (REP), overlying water (OLW) and mud flat samples (MFS) obtained from Kalarugbani Creek in Rivers State was investigated. The parameters investigated were the total viable count (TVC), salmonella-Shigella counts (SSC), total faecal coliforms (TFC) and total coliform counts (TCC). There were variations in the values of these parameters analyzed, which were sample dependent. Of all the samples analyzed, RSO had the highest microbial counts except for TFC and TCC in which periwinkle has higher counts. Statistical analysis of the mean total viable counts showed high significant differences among the four samples across various months at (p≤0.05). The microbial counts were lower in the wet season and higher in the dry season. Correlation analysis of the seasonal variations of the total viable count for the various samples showed a very weak correlation between the two seasons for MFS and OLW (r= 0.499 and r= 0.515, respectively), while those of REP and RSO were strongly correlated between the two seasons (r= 0.69 and r= 0.607, respectively). The microbial counts obtained from this study were found to be higher than the specified standard limits (1x10⁵ cfu/g) for bacteria by International Commission on Microbiological Specification for Foods (ICMSF) and United States Food and Drug Administration (USFDA). The results of this study show the presence of organisms of public health concern and highlight the need for maintenance of quality standards in the processing of these shellfish. The data obtained will be useful for the development of food safety schemes and policies.