Analyses of microbial hazards of lake Victorial Nile Perch (lates niloticus) processing at industrial level in Kenya
Mungai, Daniel N.
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The quality of processed seafood produced for international market should conform to international standards. Over the last few decades, major seafood importing countries have introduced hygiene regulations and legislation, including definitive standards for fishery products. In 1991, European Union (EU), which is the largest single market for Kenya's Nile perch products established regulations laying down health conditions for production and the placing on the market of fishery products. The kenyan Nile perch industry has been caught unaware and is not geared to meet such requirements. This led to a subsantial rejection of consignments and subsequent economic losses. Decomposition and the presence of pathogenic organisms have been indicated as the main reasons for most of these rejections. To meet the EU requirements, Nile perch processing establishments have to implement a quality control system based on the principles of Hazard Analysis Critical Control point (HACCP). Implementation of such a system requires an assessment of microbial hazards likely to occur during the processing of processing of Nile perch. To address this requirement, analyses of microbial hazards during the processing of Nile perch were conducted in two establishments over a period of eight months. The analyses consisted of observating all operations of fish processing, measuring temperature of fish throughout the processing line and collecting samples and testing them for common fish-borne pathogens and indicator microorganisms. Among the procedures followed for microviological examination of samples are those recommended by the International Commission on Microbiological Specifications for Foods (ICMSF). Results showed that the fish received at the processing establishments had aerobic mesophilic colony count (AMCC) of less than 10(6) CFU/g with hydrogen sulphide (H2S) producing bacteria accounting for less than 3 percent of AMCC. Enterobacteriaceae, coliforms, faecal coliforms and Sataphylococcus aureus counts of raw fish were within the limits recommended by ICMSF. vibrio cholerae and Clostridium perfringens were isolated only from the incoming whole fish and their incidences in both establishments were 1.4 percent and 0.5 percent respectively. Salmonella was present in 5 percent of incoming whole fish and in 16.7 percent fo fish samples collected after the fish was filleted in one establishment. Shigella spp. was not recovered from any fish sample. The processing operations in both establishments resulted in significant reduction of all the microbial parameters tested. However, it was observed that certain microbial hazards existed during the fish processing operations in both establishments, particularly under circumstances of poor handling of fish. Whole fish washing, filleting, beheading and gutting, fillet skinning, control of fish temperature and sanitation and establishment hygiene were identified as Critical Control Points (CCPs) at or by which the identified microbial hazards could be controlled. The study recommended that Nile perch processing establishments should put in place control measures aimed at eliminating, preventing or minimising the microbial hazards.