Microbial safety of selected value-added dairy products in the cottage industry in Kampala and its environs
Isabirye, Robert Alex
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The purpose of this study was to provide a better understanding of the link between production practices and microbial safety for improved marketability of locally produced value added livestock products, with special emphasis on value added dairy products, from the cottage industry. The study was conducted in Kampala metropolitan area between July 2009 and August 2010. The divisions of Kampala Central and Nakawa were randomly selected from the five divisions making up Kampala city. This study was nested within a larger cross-sectional study whose objectives were to describe small holder production/processing practices for locally produced value added livestock products in Kampala; to identify risk factors associated with value added livestock products in Kampala; and to determine the microbial safety of the popular value added livestock products consumed in Kampala, namely: ice cream and yoghurt; sausages and eggs. The cross-sectional study employed both qualitative and quantitative approaches. The quantitative part of the study utilized structured questionnaires administered by personal interview to randomly selected processors, while the qualitative approach utilized focus group discussions with processors of value added livestock products in Kampala. The structured questionnaires for processors targeted mainly respondents’ identifying information; VALPs processing factors e.g. gender; and information on marketing practices and challenges encountered during production and during marketing. On the other hand, information targeted though focus group discussions included the type of livestock products processed in a particular community, guidelines concerning production; and characteristics of smallholder processors as perceived by the different respondents. In addition, a nested study within the larger cross-sectional study was designed to determine the microbial safety of value-added dairy products processed in the cottage industry in Kampala and surrounding areas. Microbiological laboratory analyses were carried out on randomly selected samples of value-added dairy products. The product samples studied were: Yoghurt (75 samples), locally fermented milk product (locally called Bongo) (70), and Ice cream (60). These product samples were obtained at both production and marketing. Staphylococcus aureus, E-coli and Salmonella and total Plate Counts (TPC) per 25g of study dairy product for were determined. Focus Group Discussions revealed that main challenges to production and marketing of value added livestock products were lack of set standardized production criteria, high production costs due to the high electricity tariffs, expensive machinery; and lack of technical knowledge in processing. The larger survey was conducted on 224 processors of value added dairy products in Kampala and surrounding areas. Of these, 47.8% were from Kampala Central division, 38.8% were from Nakawa division while 12.5% were from Kawempe division. Survey results showed more men (69.6%) than women were involved in processing of VALPs. Awareness about guidelines concerning small scale processing of VALPs was reported to be high (74.1%). The key factors that influenced marketing decisions included quality, price, credit worthiness and demand for the products. Proper hygiene had the highest number of responses among the various guidelines (29%). In the nested study, a total 205 samples of value added dairy products were collected and tested for microbial counts. These comprised of 75 samples of yoghurt, 70 of ice cream and 60 samples of bongo. Overall, 44 (22%), 129 (63%) and 121 (59%) of the samples analyzed were above the acceptable microbial safety standards for TPC, Escherichia coli and Staphylococcus aureus respectively as set by Codex and Uganda National Bureau of Standards. Of the yoghurt samples, 65, 13 and 21% where above the maximum recommended levels of TPC, E. coli and S. aureus respectively, while, 82, 62 and 55% of the ice-cream samples where above maximum recommended microbial levels of TPC, E. coli and S. aureus. Eighty four, 27 and 24 % of the bongo samples where above acceptable levels of TPC, E. coli and S. aureus. Salmonella spp were not recovered in any of the samples tested. The mean total plate count for Kampala Central division was 2.0 x 106, while that for Nakawa division was 7.4 x 105. The means for E. coli and S. aureus for Kampala Central were 4.5 x 101 and 4.9 x 101 respectively, in Nakawa division mean counts for E. coli and S. aureus were 1.6 x 100 and 1.3 x 101 respectively. The mean TPC counts for yoghurt, bongo and ice-cream were 2.0x106, 7.4 x 105 and 7.4 x 105 respectively; while the mean E coli counts for yoghurt, bongo and ice-cream were 2.4 x 102, 6.0 x 100 and 2.6 x 100 respectively; and the mean Staphylococcus aureus counts for yoghurt, bongo and ice-cream were 2.7 x 102, 1.8x101 and 5.5 x 100 respectively. The mean counts for each organism were significantly different (p-value < 0.05). There were significant (p-value < 0.05) differences in the levels of contamination between the production and marketing stages, the latter stage having higher microbial counts as compared to the former. This finding depicts increased contamination within the marketing chain. Since this industry is largely informal, there is need for strategic interventions by local, national and international organizations to support the small scale processors through training, formation of collective groups; and subsidizing on cost of machinery and tax incentives for processors to achieve their production goals.