1 An investigation of the microbiological chain of contamination of fish products from a polluted lake (Lake Chivero), and implications for human health Francis Manjengwa 1 , P.J. Mukaro 2 and Tamuka Nhiwatiwa 1 1 University of Zimbabwe, Biosciences Department, P.O. Box MP 167, Mt. Pleasant Harare, Zimbabwe 2 Masvingo Polytechnic College, P.O. Box 800, Masvingo, Zimbabwe. Corresponding author Email: tnhiwatiwa@science.uz.ac.zw Mobile: +263-775 011 693 ABSTRACT Post harvest processing of fish products is important for good quality products as well as food hygiene. A study to determine the microbiological quality of fish from Lake Chivero was carried out at selected sites along the fish handling and distribution chain. This followed the implication of fish products in a recent typhoid outbreak in Harare. Samples were collected from lake water and several vending sites in some of Harare’s high density suburbs, and this was done on three occasions (March, August and November 2012). Bacterial indicators were used to investigate the quality of lake water, fish from the lake, and various fish contact surfaces to determine the presence and levels of contamination. Swabs on contact surfaces as well as fish samples were taken and tested for total viable bacterial count, total coliforms, faecal coliforms and Salmonella. The highest microbial load of total coliforms was recorded in Kuwadzana, Dzivarasekwa, Warren Park and Budiriro while the lowest load was observed on the cold chain, harvest waters and at White House. Salmonella sp. was present in most samples, and absent from harvest waters. This showed a prevalence of contaminated fish by pathogenic microbes. Total coliforms and faecal coliforms were present in water samples from the lake, suggesting that fish may already be contaminated. However the increase in microbial load along the fish handling chain clearly showed poor handling was resulting in further contamination. This poses serious risk to public health and the local fish trade. The points for effective intervention were the fishermen, landing sites, boats and fish traders. Key words Indicator micro-organisms, cold chain, chain of contamination, total coliforms, faecal coliforms, vending site, Swab and polluted lake.