MINERAL-COMPOSITION OF THE MILK PRODUCED IN MONTERREY, NL MEXICO

Milk is a food rich in oligoelements (approx. 1g/100 ml) that can vary in concentration due to genetic factors, type of feed, fed to cattle and due to contamination in the area of production. Since the margin b etween the concentration of mineral requirements and the toxic levels is so narrow that a little excess results harmful to sensitive species , the present study was done in the city of Monterrey, N.L. located in an industrial zone. Samples of raw milk from 17 producers distributed in 8 zones were analyzed during 6 months, measuring minerals of nutri tional and toxicological importance. All elements were determined usin g atomic absorption, except for phosphorus, wich was quantified colori metrically. Statistical significance was determined through analysis o f variance and Duncan test. The average mineral composition of the mil k analized was (mg/Lt): calcium 1179 magnesium 109.7, zinc 5.89, phosp horus 637.1, copper 0.15, cadmium <0.01, chromium <0.02, iron 0.59, le ad < 0.04, manganese < 0.02, nickel 0.36. The milk of this region is a good source of calcium, magnesium, phosphorus and zinc, with 35%, 7.4 %, 19% and 9% respectively of the RDA being obtained from a 237 ml por tion of milk.