Análises químicas qualitativas para verificar adulterações em leite pasteurizado

Abstract

The objective of this study was to evaluate the quality of pasteurized milk through physical-chemical analyses and qualitative tests in order to verify its state of preservation and identify possible adulteration. Samples of pasteurized milk from two dairies in Dourados, MS, were analyzed. The physical-chemical analyses performed to determine pH, titratable acidity (°Dornic), and density followed official methodologies from the Ministry of Agriculture. All samples had density values within the standards established for bovine milk, indicating no dilution or skimming. Acidity and pH values were also within the expected range, except for one sample that showed slight acidification due to its proximity to the expiration date. In addition, qualitative tests were applied to identify common frauds: the alizarin test to detect sodium hydroxide (NaOH) and the iodine solution test to detect starch. The evaluators were able to distinguish the adulterated samples based on characteristic color changes, demonstrating the effectiveness of these rapid methods. The UV-Vis absorption spectra of the reagents reinforced the interpretation of the visual results. The study of the physical-chemical analyses and qualitative tests as essential to ensure the milk quality and to prevent fraud.