Contaminant Assessment of Cattle Feed and Milk and Associated Health Impacts on Consumers in H-11/4 Slums, Islamabad

Abstract

Milk is a crucial part of a balanced diet, providing essential minerals, vitamins, and protein. However, contamination by heavy metals and microorganisms poses serious health risks, especially to children. In slum areas, livestock farming provides food and income, with milk being a valuable product. But, the dairy value chain lacks information on proper handling, quality control, and marketing, leading to contamination. The present study conducted at the H-11/4 slums of Islamabad, assessed the health risks associated with specific biological and chemical contaminants in dairy cattle feed and milk. Utilizing total plate count (TPC), coliform plate count (CPC), and Salmonella and Shigella plate count (SSPC), eight milk and eight feed samples from four dairy farms were examined for microbial contamination. All sixteen samples revealed significant levels of coliforms, total bacteria, and Salmonella and shigella species. The mean CPC was found to be 6.58 (log10 cfu/ml), mean TPC was 6.25 log10 cfu/ml, and a mean SS count of 5.04 log10 cfu/ml. Phosphates and nitrates were measured using a UV-visible spectrophotometric technique. The mean nitrate levels for milk samples were 11.83 mg/L, dry feed samples were 11.67 mg/L, and wet feed samples were 12.22 mg/L. Similar to this, the mean sulphate levels in milk samples were 24.3 mg/L, dry feed samples were 27.02 mg/L, and wet feed samples were 15.39 mg/L. Additionally, ICP-OES was used to assess fifteen (15) major and minor elements. The risk assessment of milk contaminants indicated HQ and CR of Ba, Cu, Al, As, and Pb, surpassing safety limits and presenting considerable health risks including potential carcinogenic risks. Study also found a significant link between feed and milk elemental contents, suggesting that feed contamination is a primary source of contaminants. A limited association between bacterial and nutritional levels indicated that contamination may result from poor milk processing and unhygienic farm conditions. The results of surveys revealed inadequate hygiene practices in dairy management, characterized by the use of tube well water for sanitation and the storage of milk at ambient temperature, fostering bacterial proliferation. Farmers were uninformed about appropriate animal husbandry, resulting in numerous cattle diseases and dependence on expensive private doctors for treatment. Overall, the milk exhibited signs of poor hygiene and indicates a possible source of milk-borne diseases. All the cattle dairy farms must ensure preventive measure as well good hygiene practice during the milk production, handling, storage, and delivery process to avoid any contamination.