Technology Details:
Neutralizers (e.g. Sodium Hydroxide, Sodium Carbonate and Sodium bicarbonate) are used for adulteration of milk to mask the developed acidity in milk. These are not permitted additives in milk as per FSSAI and their presence in milk indicates unhygienic storage of milk. A rapid paper-based strip test has been developed for the detection of neutralizers in milk. The prepared strip is yellow in color. The test involves dipping of the strip in milk samples for short duration followed by immediate visualization of color of the strip. The color of the strip changes to green or deep blue depending on the amount of neutralizer in the milk while in pure milk samples, the strip retained its original yellow color. The test strip responds immediately when brought in contact with the milk samples. The color on the strip is stable for a few hours. The developed tests is more sensitive than the existing rosalic acid test and the strip can detect presence of NaOH, Na₂CO₃, NaHCO₃ at concentration of 0.03, 0.06, 0.1%, respectively in milk. Normal processing of milk such as pasteurization, boiling etc does not affect the efficacy of the strip. The colour distinction between adulterated and non-adulterated milk is clear. Differentiation between adulterated and non-adulterated milk can be made instantaneously. The shelf life of the strip is more than 6 months at room temperature. The test can be performed even by non-technical person. The method has been validated at a NABL accredited laboratory. The test can be used at Milk Collection Center, Reception Dock of Dairy Industries and also at House hold levels.