ASSESS PREVALANCE AND IMPACT OF WATER ADULTERATION ON MILK COMPOSITION AND STANDARDS

Abstract

Milk quality is critical for ensuring public health, consumer confidence, and the production of safe dairy products. However, the adulteration of raw milk with water remains a common form of food fraud that compromises its nutritional composition and quality. This study assessed the prevalence and impact of water adulteration in raw milk and evaluated variations in milk composition across dairy farmer groups in Bhutan to provide baseline information for developing milk quality standards and implementing a quality-based milk pricing system. A total of 6,665 raw milk samples were collected from 52 Gewogs across 17 Dzongkhags between July 2022 and June 2024 and analyzed for major compositional parameters. The results revealed that 25.33% of the milk samples were adulterated with water. Water adulteration significantly reduced milk fat, protein, lactose, solids-not-fat (SNF), ash content, and freezing point values, thereby lowering the nutritional quality of milk. Considerable variation in milk composition was observed among Dzongkhags. Wangdue, Trongsa, and Lhuntse Dzongkhags exhibited comparatively higher milk quality, characterized by elevated fat, SNF, protein, lactose, and ash contents, whereas Thimphu and Tsirang Dzongkhags recorded lower compositional values and a higher prevalence of water adulteration. The findings highlight the widespread occurrence of water adulteration and its adverse effects on milk quality. Strengthening routine quality monitoring, establishing rapid adulteration testing facilities at milk collection and processing centers, and implementing quality-based milk payment systems are recommended to improve milk quality, protect consumers, and support the sustainable development of the dairy sector.