Influence of physical state of farm housing and processing facilities on quality and safety of dairy milk products.
Paraffin, Annah Shingirai.
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The broad objective of the study was to determine the influence of physical state of farm housing and milk processing facilities on the quality and safety of milk and its products. Data collected from urban areas (n =135) and non-urban areas (n =135) households were used to investigate consumer perceptions of milk safety and consumption preferences of dairy products. Data collected from large-scale dairy farmers (n=158) and small-scale dairy farmers (n=186) were used to investigate the perception of milk producers on milk quality and safety. Milk records collected from large-scale dairy farms (n =78) and small-scale farms (n =126) were used to determine the effect of physical state of farm housing and milking practices on total bacteria counts (TBC), somatic cell counts (SCC), protein, butterfat (BF), solids non-fat (SNF), lactose and total solids (TS). Milk records collected from large-scale (n =12) and small-scale (n = 15) dairy processors were used to estimate the influence of physical state of milk processing facilities on presence of E. coli and coliforms in buttermilk. Urban households were 2.8 times more likely to consume fresh milk compared to their non-urban counterparts (P < 0.05). Households from urban areas were twice more likely to purchase fresh milk from kiosks, while households from non-urban areas were five times more likely to buy fresh milk from vendors. The likelihood of appearance, quality and nutritional value being important to households during selection of milk products was higher in urban locations compared to non-urban locations (odds ratio estimates of 4.29, 4.49 and 6.75, respectively). Knowledge and awareness of milk safety issues was more important to urban households. Large-scale farmers were three times more likely to consider breed affecting milk quality compared to their small- scale counterparts. Post milking contamination of milk was perceived to occur during transportation by small-scale farmers, whilst large-scale farmers ranked storage as an important source of contamination post-milking. The likelihood of milk safety being important was twice higher in large farms compared to small-scale farms (P < 0.05. The majority (70%) of large-scale farms had milking parlour doors, windows and fly proofing in poor physical state. More than fifty percent of small-scale farms had milking parlour doors, windows and fly proofing in good physical state (P < 0.01). Most of the large-scale farms used pumps to deliver their milk to storage tanks whilst most of the small-scale farmers used the pouring method (P < 0.05). The TBC and SCC in milk from dairy farms where the wash rooms that had doors, floors, walls and ventilation were in a good physical state were higher than from those farms where the wash rooms were in poor physical state (P < 0.05). Farms that used machine milking and automatic milking cleanings system had lower TBC and SCC in milk compared to farms that used manual milking or hand washing (P < 0.05). The butterfat and protein content in milk from dairy farms with milking facilities that had poor physical state of ceilings, ventilation and floors was lower than those in good physical state (P < 0.05). The butterfat, protein, lactose and solids non-fat (SNF) content in milk from farms that utilised hand milking was higher than dairy farms that used milking machines (P < 0.05). The likelihood of buttermilk from processors with buildings, processing and packaging areas that had poor physical state of drains, roofs, fly-proofing, windows having E. coli and coliforms was 1.2 times higher than those facilities in good physical state. Processors without quality assurances systems or food safety training were twice more likely to produce buttermilk contaminated by E. coli and coliforms (P < 0.05). Poor physical state of ceilings, doors and floors and poor drainage systems at farms results in production of milk with high bacterial count and presence of E. coli and coliforms in buttermilk.