Self and Foreign Substances in Organic and Conventional Milk Produced in the Eastern Region of Mexico

摘要

The objective of the present study was to evaluate the physicochemical properties, presence of water and aflatoxin M1, as well as the effect of the time of year (dry or rainy season) to value the quality and safety of conventional and organic raw milk samples. Samples were collected of conventional (n = 12) and organic (n = 11) raw milk from Tizayuca, Hidalgo and from Tuxpan, Veracruz, respectively. Infrared spectrophotometry and other analytical techniques were employed, approved by the International Dairy Federation for the analysis of the physicochemical properties, the cryoscopy technique for the detection of water addition, and high performance liquid chromatography for the determination of aflatoxin M1. Results showed that there are no significant differences in the components of conventional milk in the season of the year, whereas in organic milk a significant difference (P 0.05) was observed in acidity during the seasons of the year (rainy and dry), as well as a decrease in the percentage of lactose in the dry season, with a significant difference (P 0.05). The means of the cryoscopic point of the milk samples complied with the limits established in the Mexican Official Norm (–0.530, –0.560°H) for milk and no effect was found of the time of year on this variable. Of the milk samples, 50% of the conventional milk and 54.55% of organic milk were above the maximum limits permitted for aflatoxin M1, established in Mexico (0.5 μg·Kg-1).