Assessment of the prevalence of pathogenic bacteria in street vended ready-to-eat meats in Windhoek, Namibia
Loading...
Date
2017
Authors
Wetuhafifa, Shiningeni D.
Journal Title
Journal ISSN
Volume Title
Publisher
University of Namibia
Abstract
While street vended ready-to-eat meats provide a source of readily available and nutritious meals for the consumers, there is a concern for their safety and microbiological quality. The prevalence of E. coli, Salmonella, Shigella, L. monocytogenes, S. aureus and Enterobacteriaceae was assessed in a total of 96 street vended ready-to-eat meat samples collected from Windhoek locations, namely, Katutura, Prosperita and Dorado Park. Selective media was used to assess aerobic plate count, Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, Shigella, Salmonella and Enterobacteriaceae. Biochemical confirmation tests were employed using the conventional biochemical tests and the VITEK® 2 system. The data showed that 42%, 15%, 6%, 52% and 83% of the samples were positive for E. coli, L. monocytogenes, Shigella, S.aureus and Enterobacteriaceae respectively. The highest bacteria counts obtained for aerobic plate count, E. coli, S. aureus, L. monocytogenes, Shigella and Enterobacteriaceae were 7.74 log cfu g-1, 5.67 log cfu g-1, 5.12 log cfu g-1, 4.56 log cfu g-1, 3.3 log cfu g-1, 5.75 log cfu g-1 respectively. Unsatisfactory microbial levels were 32% for aerobic plate count, 26% for Enterobacteriaceae, 35% for E. coli, 11% for L. monocytogenes, 7% for S. aureus and 6% for Shigella. Salmonella was only detected after enrichment of culture media in 11% and 40% of samples from two Katutura surburbs, Wanaheda and Havana respectively, which made the samples potentially hazardous. The Tukey’s multiple comparison test showed that the prevalence of E. coli was significantly higher in samples purchased from Havana than other locations sampled (p < 0.05). Pearson’s correlation tests showed significant positive correlation between the prevalence of E. coli and the collection time of meat samples (r=0.449, p=0.000). None of the samples was found to be positive for enteropathogenic E. coli. This study has helped to bridge a gap in knowledge by establishing the prevalence of pathogenic bacteria of public health concern in street vended ready-to-eat chicken and beef in Windhoek, Namibia. The unsatisfactory microbiological quality of some ready to eat meats determined in this study may be due to inadequate processing and poor handling practices, necessitating the provision of training on food safety and hygiene for street vendors for consumer protection. The relationship between the sampling locations, type of meat, preparation methods, serving temperature and the time of purchase and the prevalence of pathogenic bacteria has also been established. Further studies may include assessment of prevalence of food poisoning resulting from consumption of ready-to-eat meats. Moreover, assessment of microbiological quality of other popular street vended ready-to-eat foods in Namibia such as fruits, fat cakes and salads, as well as the microbiological quality of some meat ingredients like spices, onions and tomatoes and their effect on the microbiological quality of ready-to-eat meats.
Description
A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Science in Microbiology
Keywords
Pathogenic bacteria