Is your milk safe? Scientists with the Agricultural Research Service (ARS) have joined forces with the Regional Dairy Quality Management Alliance (RDQMA) to make sure it is. RDQMA is a group of state veterinarians, Extension personnel and university scientists in 10 northeastern and mid-Atlantic states who are interested in dairy-related issues.
In 2003, ARS began working with RDQMA to develop a set of best management practices for dairy producers. These practices are designed to minimize the risk of diseases caused by microbial pathogens in dairy cows and dairy products, and assure the maximum safety of the products as they leave the farm.
The collaborative research team consists of the ARS Environmental Microbial Safety Laboratory in Beltsville, Md.; the ARS Antimicrobial Research Laboratory in Athens, Ga.; Cornell University, Pennsylvania State University, the University of Pennsylvania and University of Vermont.
A pilot project, begun in January 2004, originally involved a 300-cow herd in New York and a 100-cow herd in Pennsylvania. A third herd in Vermont was recently added. The researchers collect biological samples from the herds, such as blood, manure and bulk tank milk, as well as environmental samples, such as bird droppings, water, feed and soil. The samples are distributed to university and ARS researchers who test them for the presence of pathogens such as Salmonella, E. coli O157:H7, Listeria monocytogenes and Campylobacter.
One sampling at one of the test farms revealed that although 45 percent of the cows tested positive for Salmonella, no Salmonella was actually detected in the bulk tank milk, according to ARS microbiologist Jeffrey Karns at Beltsville. Molecular genetic techniques are used to detect particular strains of Salmonella, Listeria and E. coli. This type of analysis helps differentiate between those that are harmful to humans and those that are not.
