Levels of microbial contamination on the differently preserved Oreochromis niloticus fish samples at Kasenyi landing site

Abstract

Fish play an important role in the human diet due to their peculiar protein content peculiar lipid composition. Fatty fish contains vitamins A and E in their muscle tissue while low-fat fish possess fat soluble vitamins stored in the liver with immense nutritional and health gains when consumed. However, in spite of the nutrition attributes of the fish, Uganda‟s per capita consumption still remains low with current estimations at 5.7 kg lower than the world average of 20.1 kg annually. Compounding this somber situation, is the fact that fish, is a highly perishable food with moisture properties which make it suitable for microbial growth. Some of the microorganisms that deteriorate preserved Nile tilapia are bacteria, fungi, among others. Fish is prone to microbial contamination through contact with soil, dust and water during post-harvest handling including processing. The study aimed at examining levels of microbial contamination in relation to the mode of Nile tilapia preservation. Fish samples of Oreochromis niloticus were collected from market vendors and at Kasenyi landing site. At the market section, the interviews were also done from the vendors from which the samples were obtained. The collected fish samples were then transported to Makerere University Biotechnology laboratories in the department of Plant Sciences, Microbiology and Biotechnology for microbial assessments. The choice and application of the preservation method used by the vendors were qualitatively assessed through the use of interview guides. Smoked fish had the highest level of microbial contamination of 4.54x108CFU/ml followed by salted fish at 3.02x108 CFU/ml. Frozen fish had the lowest microbial load at 2.1X107 CFU/ml. Interview guides revealed the concept that hygienic behavior consists of simple antiseptic actions though most individuals found it hard to adapt to them due to the various factors like not adhering to the laws governing the hygiene of the landing site. The principles applied both to the people who handle the catch and equipment that the fish comes into contact with. The basic hygiene concepts covered included personal hygiene rules for people handling the catch along the supply chain from capture or harvest to consumption, including personal hygiene and dress codes. The results further revealed that the vendors that preserved fish by freezing adhered more to the sanitary rules that those of the other preservation methods. In conclusion, preservation therefore becomes a very important part of commercial fisheries. It is therefore recommended that for the fisheries sector to remain sustainable for a long time, with a minimum loss of flavor, taste, odour and nutritive value, the government should put up strict measures on the vendors to mitigate spoilage of fish and fish products depending on a number of factors most so the hygienic conditions that if not well observed could lead to post-harvest losses.