Assessment of physicochemical quality parameters of milk and levels of enrofloxacin residues in milk sold at distribution outlets within Kampala capital city

Abstract

Milk is a highly nutritious food that is consumed widely within Uganda. Due to its demand, the quality parameters and drug residue levels are often overlooked by final consumers. This has prompted rogue persons within the supply chain to adulterate milk with water to increase its volume and with preservatives like formaldehyde to prevent it from spoilage. However, these adulterants affect the physicochemical parameters of milk like pH, titratable acidity, freezing point, and hence its quality. Milk is also stored in a refrigerator to prevent it from spoilage, but this leads to the breakdown of lactose by bacteria within the milk to form lactic acid which eventually affects its acidity.

Milk-producing animals like cows often acquire diseases and drugs like enrofloxacin are used to treat infections in the respiratory, digestive, urinary, joint, reproductive, mammary, and dermal regions. This drug is however metabolized, and its residues are excreted in milk. The presence of these residues further affects the quality of milk and also exposes the consumer to sublethal quantities of enrofloxacin residues which subjects the consumer to negative effects like emergence of drug resistant microorganisms.

Assessment of milk quality needs to be done daily due to the daily milk production however the costs attached to the assessments are high and some require the use of sophisticated equipment like High-performance liquid chromatography (HPLC) which are not easily accessible. Failure to assess milk daily increases the risk of consuming poor-quality milk by the consumer.

Assessment of milk quality and enrofloxacin residues are indispensable aspects of food safety and are a mammoth step in tackling global food safety and antimicrobial resistance to enrofloxacin and its active metabolite ciprofloxacin.

This study assessed the milk quality and levels of enrofloxacin residues in milk sold at distribution outlets within Kampala Capital City to ascertain if it meets the minimum standards.