Nothing is quite as satisfying as a tall, cold glass of milk, but odd flavors can be off-putting to consumers.
Researchers at Virginia Tech have traced what could be one indicator of contamination when milk’s flavor profile turns sour — too much iron in cows’ water sources.
A collaborative research effort involving the departments of dairy science, food science and technology, biochemistry, and civil and environmental engineering discovered that iron in bovine water sources was causing oxidized flavors, degraded milk proteins, and general poor stability of milk products. High iron content also decreased the cow’s ability to efficiently process some types of nutrients, which decreases production levels and makes the animals susceptible to a host of other health issues including mastitis and other bacterial infections.
“We found that when iron was present in the water or we added iron, we got a flavor profile that was less than ideal,” said Susan Duncan, professor of food science and technology and one of the lead authors in the iron study.
“While producers may not see the effects of iron in their milk quality immediately, over time this could pose a problem for producers who might notice a decline in quality and sales for no apparent reason.”
More than 80 percent of milk is water, and dairy cows drink about 100 liters of water each day to produce milk.
The amount of iron needed to contaminate milk was as low as 2 milligrams per liter.
“This study uncovered what could be a new baseline recommendation for producers who will likely want to test their water sources and collection and transportation equipment to ensure the iron levels are not too high from any of their sources,” Duncan said.