Degree

Doctor of Philosophy (PhD)

Department

Animal Science

Document Type

Dissertation

Abstract

Multiple studies were conducted in Malawi to: 1) evaluate knowledge and perception of dairy farmers towards molds, mycotoxins and associated adverse effects; 2) evaluate dairy farmers’ knowledge and perception on milk contamination, proper milk handling practices and adverse health effects associated with raw milk consumption; 3) determine levels of aflatoxins and zearalenone (ZEN) in concentrate feedstuffs; 4) assess prevalence and levels of aflatoxin M1(AFM1) in raw milk, dietary exposure and estimate HCC risks to children and adults; 5) assess Salmonella and E. colicontamination in raw and processed milk from selected small scale farms and major food stores, respectively. A total of 130 and 113 concentrate feedstuff and milk samples, respectively, were collected from selected farms. Feed samples were analyzed for total aflatoxin and ZEN while milk samples were analyzed for AFM1. Eighty-seven processed and raw milk samples were collected from selected food stores and dairy farms for E. coliand Salmonellaanalysis. Less than 50% of dairy farmers were aware of negative effects associated with mycotoxins and perceived mycotoxins as risky to humans and dairy animals. About 60% of the dairy farmers never thought mycotoxins in dairy cows’ feeds could be carried over to milk hence no risk associated with consumption of that milk. The majority of dairy farmers had low knowledge on proper milking and milk handling practices with 77% keeping milk for >6 hours at room temperature and none following all necessary milking steps. Frequency of presence of E. coli(76.1%, n = 46) and Salmonella(26.1%, n = 41) in raw milk samples was significantly higher than in processed fluid milk. Population risk of AFM1-induced HCC were low, estimated at 0.038 and 0.023 cases/100,000 individuals/year for children and adult consumers respectively. Few milk samples (22%) had AFM1above Malawi regulatory limit of 0.5 ppb. Total aflatoxin (0.5 – 410 ppb) and ZEN (50 – 2400 ppb) were present in all concentrate feed samples with non-significant effect of agroecological zones. Current situation calls for training of dairy farmers and frequent monitoring of dairy products quality to seal the gaps identified in these studies.

Date

8-21-2019

Committee Chair

Moreira, Vinicius

Available for download on Thursday, December 31, 2020

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