Assessment of Raw Milk Quality at Selected Chilling Centers in the North Central Province of Sri Lanka

Abstract

Cow's milk is a vital and highly nutritious food for consumers, and its quality significantly influences dairy production practices. The quality of raw milk depends on its chemical composition, serving as the basis for evaluation. While standardized testing processes are commonly used to assess milk quality in industrialized nations, Sri Lanka lacks comprehensive regional databases for monitoring milk quality. This research aimed to identify key quality parameters of raw milk from selected milk chilling centers in selected areas such as Kahatagasdigiliya, Galenbidunawewa, Thambuththegama, Siwalakulama, Kekirawa, Padaviya, Medawachchiya, Welikanda, Nochchiyagama, Srawasthipura, Saliyapura, Rabawa, and Higurakgoda of the North Central Province of Sri Lanka. The analyzed parameters included fat, solid non-fat, lactose, protein, added water, freezing point, corrected lactometer reading, pH, keeping quality , solubility index and milk stability, all of which help assess the quality of raw milk in compliance with established standards. Milk samples were analysed using ultrasonic milk analysers, pH meters, alcohol precipitation tests, and resazurin dye reduction tests. The quality status was determined using mean comparisons and process control charts. The results revealed the mean quality values of milk from selected areas of North Central Province as follows: pH (6.19±0.14), fat (3.95±0.08%), solid non-fat (8.46±0.16%), protein (3.27±0.06%), lactose (4.87±0.11%), corrected lactometer reading (27.48±0.08), added water (0.13±0.01%), freezing point (0.57±0.03℃), solubility index (0.69±0.01 mg/L), and keeping quality (2±0.03). Additionally, 96% of the samples yielded negative results in the alcohol precipitation test. Based on the findings, none of the regions studied consistently produced raw milk that met the established SLS quality standards. Common deficiencies were observed in parameters such as fat content, solids-not-fat (SNF), pH, and keeping quality. These widespread quality issues highlighted the need for targeted interventions at the grassroots level. Educating dairy farmers on proper milking practices, hygiene, feeding, and milk handling is essential for improving milk quality and ensuring compliance with national standards.