Tag Archives: food safety

Got high-quality milk?

IMG_0211Nothing 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.

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Improving milk quality proves profitable for Virginia farmers

A Virginia Tech student milks cows at the new Dairy Science Complex – Kentland Farm.

A Virginia Tech student milks cows at the new Dairy Science Complex – Kentland Farm.

Virginia generates 1.7 billion pounds of milk per year.

Though the dairy industry  in Virginia is small compared to other states, the commonwealth produces 207 million gallons of milk annually, worth about $481 million according to the Virginia State Dairymen’s Association.

However, hot, humid summers add challenges to milk production in the region. Reduced milk quality results in increased production costs for farmers while decreasing revenues and sustainability.

Christina Petersson-Wolfe, associate professor of dairy science and Extension specialist, wants to help improve the quality of the state’s milk.

Petersson-Wolfe, working with the Southeast Quality Milk Initiative, is helping dairy producers in the commonwealth and the region compete more effectively by lowering bacterial counts in milk, thus commanding better prices in the marketplace. Virginia Tech has partnered with the University of Tennessee, University of Kentucky, University of Georgia, and University of Florida to implement the $3 million multistate project funded by the U.S. Department of Agriculture.

Milk quality is commonly measured by the somatic cell count and standard plate — or bacteria — count. Most buyers in the region require the milk they purchase to have a somatic cell count of fewer than 400,000 cells per milliliter, but farmers strive to attain a count closer to 200,000.

Since the inception of the program, the average somatic cell count in Virginia has dropped 5.8 percent. These numbers can add up when dairy farmers receive their milk premiums — cash above and beyond the standard rate of about $17 per 100 pounds. Premiums can add up to thousands of dollars per month. One dairy farm that benefited from consultation with the milk initiative saw an increase of $8,640 per month.

“Our overall goal is to enable dairy farmers to move toward production systems compatible with a sustainable industry,” said Petersson-Wolfe.

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