Water and Manufacturing Process Effect on Cow’s Milk Content in Essential Inorganic Elements

Abstract

The objective of this study was to determine the effects of mineral content of drinking water on mineral content of cow’s milk, and to evaluate the effect of skimming process on mineral content of milk. The mineral content of milk is particularly important to the infant food formula industry, whilst milk products cover significant proportion of adult requirements in inorganic elements. Presently water is not considered feed and official controls in EU are restricted to complete feed for ruminants (complementary feed and forages), excluding water quality and content. Nevertheless, water is the main constituent (87%) of milk. Thirty Holstein Friesian cows, with the same milk production; parity and stage of lactation where randomly allocated in to two equal groups and fed the same ration but had access to different water supply, in a changeover design. Additionally, milk samples with different fat content 0, 1.5 and 3.5% were taken during the year, from manufacturing milk supplies, representing the 90% of Greek milk pool. The elements determined were Ca, Mg, Zn, Mn, Cu, Fe by the use of atomic absorption spectroscopy, and P was determined through UV-VIS spectrophotometer. Water did not have significant effect on the content of Ca and P but significant effect on Mg, Cu and Mn content of milk. Milk fat removal significantly increased the content of Ca, P, and Mg. Manufacturing process did not affect micro element content. The elements Zn and Fe were not affected by manufacturing process neither by drinking water. Food composition tables should be updated as macro mineral content of milk is reduced gradually corresponding to higher yielding cows; whilst trace element content tend to increase as a result of higher proportion of concentrates fed.

Keywords

• drinking water
• cow’s milk
• inorganic elements
• skim milk