Determination of risk factors contributing to microbial contamination in milk and identification of presence of selected pathogenic bacteria along dairy value chain in Tanga

Contaminated milk is responsible for up to 90% of all dairy-related diseases of humans. A cross sectional study was carried out in Lushoto and Handeni districts of Tanga region to determine handling practices, bacterial contaminations and selected milk-borne zoonotic pathogens along the dairy value chain. A total of 93 respondents were interviewed and subsequently 184 samples of milk and its product were collected for laboratory analysis of total plate count (TPC), coliform plate count (CPC), and detection of Escherichia coli O157:H7 and Brucella abortus using polymerase chain reaction (PCR). Results showed 57% of famers milked their cows under unhygienic conditions and plastic containers were used for storage. Although the mean total plate count was exactly within the East African Standards (EAS, 5.3 log10 cfu/ml) the counts ranged between 3.3 log10 to,5.8 log10 where 87% and 93% of milk from farmers and vendors, respectively, were above the acceptable EAS standards. Meanwhile, 100 % of milk samples were above CPC EAS standards. PCR analyses did not detect E.coli O157:H7 in all the tested milk samples while B. abortus was detected in 37 out of 87 samples tested (42.5%). It was concluded that limited veterinary/extension services, unhygienic practices of milking and post-harvest handling along the dairy value chain possibly contributed to microbial contamination of milk. Detection of B. abortus in milk is of public health significancy due to its zoonotic potential. It is recommended that veterinary/extension services should be provided to livestock farmers on proper animal husbandry and control of diseases

Risk of imported malaria infections in Zanzibar: a cross-sectional study

BACKGROUND: Zanzibar has made substantial progress in malaria control with vector control, improved diagnosis, and artemisinin-based combination therapy. Parasite prevalence in the population has remained around 1% but imported infections from mainland Tanzania contribute to sustained local transmission. Understanding travel patterns between mainland Tanzania and Zanzibar, and the risk of malaria infection, may help to control malaria importation to Zanzibar. METHODS: A rolling cross-sectional survey linked to routine reactive case detection of malaria was carried out in Zanzibar between May 2017 and October 2018. Households of patients diagnosed with malaria at health facilities were surveyed and household members were tested for malaria using rapid diagnostic tests and a sub-sample by quantitative PCR (qPCR). Interviews elicited a detailed travel history of all household members who had travelled within the past two months, including trips within and outside of Zanzibar. We estimated the association of malaria infection with travel destinations in pre-defined malaria endemicity categories, trip duration, and other co-variates using logistic regression. RESULTS: Of 17,891 survey participants, 1177 (7%) reported a recent trip, of which 769 (65%) visited mainland Tanzania. Among travellers to mainland Tanzania with travel destination details and a qPCR result available, 241/378 (64%) reported traveling to districts with a 'high' malaria endemicity and for 12% the highest endemicity category was 'moderate'. Travelers to the mainland were more likely to be infected with malaria parasites (29%, 108/378) than those traveling within Zanzibar (8%, 16/206) or to other countries (6%, 2/17). Among travellers to mainland Tanzania, those visiting highly endemic districts had a higher odds of being qPCR-positive than those who travelled only to districts where malaria-endemicity was classified as low or very low (adjusted odd ratio = 7.0, 95% confidence interval: 1.9-25.5). Among travellers to the mainland, 110/378 (29%) never or only sometimes used a mosquito net during their travel. CONCLUSIONS: Strategies to reduce malaria importation to Zanzibar may benefit from identifying population groups traveling to highly endemic areas in mainland Tanzania. Targeted interventions to prevent and clear infections in these groups may be more feasible than attempting to screen and treat all travellers upon arrival in Zanzibar

The use of polymerase chain reaction (PCR) to confirm presence of selected pathogenic bacteria along milk value chain in Tanga region

BACKGROUND Despite the fact that foods of animal source are a minor constituent in most diets, they are responsible for incidents of food-borne illness; dairy products being implicated. Up to 90% of all dairy – related diseases are due to pathogenic bacteria found in milk. Emergence of new milk-borne bacterial pathogens with more serious challenges such as E.coli O157:H7 has been reported. OBJECTIVES The main objective was to determine milk-borne zoonotic risks associated with milk handling and storage along the dairy value chain. Specific objectives included: 1. To assess possible sources of microbial contamination of milk from farm to consumer 2. To identify practices that lead to microbial contamination along the milk value chain 3. To enumerate total number of bacteria and coliforms present in milk 4. To assess presence of E. coli and B. abortus along the milk value chain MATERIALS AND METHODS Milk samples and questionnaires from all the actors along the dairy value chains of Handeni and Lushoto districts in Tanga region were collected. The questionnaires were analyzed using Stata/IC 11 while standard microbiological cultures and polymerase chain reaction were used to identify and confirm microbial contamination in milk. RESULTS A total of 184 (118 farmers, 4 collection centres, 16 restaurants, 35 vendors, 11 consumers) milk samples were collected and a total of 81 (65 farmers, 11 restaurants, 15 vendors). A checklist of questions for four collection centres was also filled. From the sociological data, different practices that could lead to microbial contamination of milk during milking, storage and delivery were identified. Preliminary analysis showed that only 43 % of farmers cleaned the animal shed before milking, only 71 % washed hands before milking, and, only 71 % of farmers washed the cows’ teats before milking. Detailed results of the study, including laboratory results and sociological results are presented

Quality of milk obtained in informal channels in Tanzania as revealed by integrated assessments

There is increasing concern regarding the quality and safety of milk collected and consumed in Tanzania. The majority of milk is obtained in informal distribution channels where animals have unknown health status and good milking and handling practices are often not observed. These factors may contribute to the contamination with milk-borne diseases and milk quality loss. Investigations of the dairy value chain in Tanzania included surveys, key informant interviews, participatory rural appraisals, and laboratory analyses. Our results show a dynamic informal milk sector with rural-rural as well as rural-urban value chains with a diversity of consumers who appreciate milk for its nutritional value and show little concern for milk- borne hazards. Milk samples showed high bacteria and coliform counts exceeding standard levels in the East African Community, e.g. total bacterial count of 1.0 × 107 colony forming units per millilitre (cfu/ml) and total coliform counts of 1.1 × 107 cfu/ml. Ten bacteria species were isolated from milk samples, andfive of these, Pseudomonas aeruginosa, Listeria monocytogenes, Listeria innocua, Listeria ivanovii, and Klebsiella spp. are rarely reported in Tanzania. Furthermore, adulteration and residues of tetracycline and sulfonamide, were detected. It is recommended to work towards solutions that take an interdisciplinary and cross-sectoral approach to promote a product of nutritional value that is safe to consume