Intentional fraud in UHT whole milk to evaluate the effectiveness of the density and titratable acidity test

Abstract

Milk is a food rich in nutrients, these attributes make the production of milk gain prominence and lead to a more careful look at its production, especially in the quality of its product. RIISPOA considers normal milk to be a product that has the following characteristics: minimum fat content of 3.0g/100g; titratable acidity between 0.14 to 0.18 expressed in grams of lactic acid/100 mL; relative density at 15°C/15°C between 1.028 and 1.034. Initially, milk adulteration aimed to increase the volume. Subsequently, new types of adulteration emerged, such as the addition of cheese whey, preservative substances (hydrogen peroxide), neutralizing substances (sodium hydroxide, sodium bicarbonate) and density constitutors and cryoscopy (salt, sugar, starch). The addition of cheese whey, as it has a composition of water, lactose and mineral salts, has physicochemical characteristics, such as density and cryoscopic index, very similar to those of milk. The presence of urea in the milk is used to increase the volume, and as it has a density very close to that of milk, the change is very small. The Ministry of Agriculture, Livestock and Supply's manual of physic-chemical and microbiological methods of analysis of products of animal origin contains the official analytical protocols for the control of milk and dairy products. The work verified the efficiency of Dornic acidity and density tests in intentionally swiped milk with different concentrations of bovine urine and cheese whey. For this, 12 liters of whole UHT milk, of the same brand and batch, were purchased in commercial establishments in the Federal District. These were transported in their own packaging and in isothermal boxes to the physical-chemical analysis laboratory at the ICESP University Center – DF. The addition of cheese whey detected a slight change in density and titratable acidity, still remaining in accordance with the legislation, which demonstrates that cheese whey is susceptible to fraud. The addition of cattle urine showed no detectable changes in density and titratable acidity, showing that there is a possibility of fraud, even if it remains within the standards and consecutively masking its detection. Thus, there is a need for new technologies that can detect lower concentrations of whey and bovine urine addition, making the food safer for consumers in case of adulterations in milk.