Assessment of raw milk quality in smallholder dairy farms in Mwanza City, Tanzania

Milk quality is determined by the hygienic standards, nutritional quality and health status of the lactating animal. However, animal husbandry practices, unhygienic milking procedures and practices may affect its quality and safety. A cross-sectional study using questionnaires was conducted to determine the socioeconomic characteristics of the participating farmers, milking practices, adulteration rates, and prevalence rates of mastitis and brucellosis in the Mwanza Municipality. Additionally, a lactometer, the California mastitis test (CMT) and the milk ring test (MRT) were used to establish the status of milk quality. Socioeconomic data revealed that livestock was the major source of income and protein for 17.2% and 32.8% of the households, respectively. The main purposes of keeping cattle were income generation (37.5%), milk for household use (36.7%), and manure (21.1%) for crop farming. The breeds of cows used for milk production were mostly Friesian crosses (58.3%). A total of 50% of the cattle houses were roofed, and 45.3% were built with concrete floors, with 62.5% having well-built feeders and 56.3% having well-built drinkers. During milking, cleaning towels, teat dips, and aluminum containers were used by 43.8%, 3.23% and 7.81% of the households, respectively. Approximately 29.7% of the milk samples obtained were tainted, whereas 55.5% and 3.1% of the samples tested positive for CMT and MRT, respectively. The prevalence rates of clinical and subclinical mastitis at the cow and quarter levels were 5.1%, 20.7%, 55.5% and 10.1%, respectively. Laboratory analysis revealed that Coliform spp., Staphylococcus spp. and Proteus spp. colonies dominated the samples that tested positive for CMT. The corresponding rates were 40.6%, 17.2% and 11.8%, respectively. The study revealed the need to increase farmers’ capacity for hygienic milk production and enforce guidelines for quality milk production in the area.