Análises de rotina para controle de qualidade do leite e detecção de fraudes: limitações e proposta de equação para quantificação da qualidade.

Abstract

Milk is very important for a healthy diet, because it is a source of energy and nutrients and is part of the Brazilian's eating habits. The agroindustrial chain of milk has great importance in food supply, job creation and income, because it is present daily in people's lives. Thus, methods of analysis for fraud detection and quality assurance of milk are of great importance. The standardization of milk is done by the Normative Instructions no 62/2011 and no 68/2006. However, the methods currently used in this control have limitations such as low portability, high cost and need of trained professionals and are often not conclusive due to natural milk variations. In addition, the techniques can be mocked through mixed fraud, where two or more substances with pre-defined concentrations are added in order to mask the methods of analysis. In view of this, there is a need for the simultaneous use of several methods to increase the reliability of the analyzes. However, the results tend to be confused and unrelated, as well as presenting only qualitative results. Therefore, the proposal of this work is an equation to organize this information and qualify the milk in a quantitative way, based on a quality concept attributed from a note coming from the equation. The analyzed samples were of refrigerated raw milk produced in the State of Minas Gerais. The physicochemical analyzes were performed at the Multi-user Chemistry Laboratory of the Department of Pharmacy, Federal University of Juiz de Fora, in Governador Valadares. Density, cryoscopy, pH, Dornic acidity, fat content and electrical conductivity were measured. The analyzed samples were of refrigerated raw milk produced in the State of Minas Gerais. In this work, deliberate frauds were also prepared in order to evaluate the efficiency of the proposed mathematical equation. Water, cheese whey, salt, ethanol, sodium bicarbonate and hydrogen peroxide were added. The results showed that the proposed equation is able to qualify the milk in a quantitative way and that the grades obtained in the milks analyzed were in agreement with the conditions prepared in the samples.