EVALUATION OF BLUEBERRY EXTRACT AS A NATURAL pH INDICATOR FOR MILK QUALITY ANALYSIS

The study proposes natural pH indicator from blueberry extract for assessing milk quality. Extract rich in anthocyanins (202.22 mg/L), was tested on pasteurised, raw, and spoiled milk and compared with conventional methods like MBRT and resazurin test. pH-colour calibration chart was prepared showing colour change from pH 1 to pH 9. Method validation showed good linearity (R² = 0.9974), precision (%RSD = 2.80%), LOD of 0.083, and LOQ of 0.252. Pasteurised milk shows no colour change up to 5 hours of incubation, raw milk changed its colour and texture after 4 hours, and spoiled milk showed an immediate response, consistent with conventional test results. In conclusion, blueberry extract is a simple and eco-friendly alternative for rapid milk quality testing.