The Food and Drug Administration (FDA) along with state health regulators approved a process this week that will likely increase testing for drug residues in milk. The action was taken at the National Conference on Interstate Milk Shipments (NCIMS) held in Portland, Ore.
NCIMS, comprised of state health departments and the FDA, regulate the Pasteurized Milk Ordinance (PMO), which establishes rules for interstate shipment of Grade A milk. It meets once every two years to consider changes to the PMO.
The reasons for increased testing were varied, including drug residues found in an FDA survey of nearly 2,000 U.S. dairy farms that was released earlier this spring. See “FDA finds U.S. milk supply safe” in our April issue.
In that survey, FDA found 16 residues on 15 farms. The violation rate was just 0.7%, but large enough to cause concern that a few dairy farmers are still using antibiotics illegally or not paying attention to withholding periods.
The FDA survey screened for drugs other than Beta-lactams, which already are tested for in every tanker load of milk. Florfenicol accounted for 10 of the 16 violation levels. It is not approved for dairy cattle older than 20 months of age.
One of the big issues with increased testing for many of the drugs found in the farm survey is that rapid tests are currently not available or officially approved for use. For example, there is currently no rapid florfenicol test that yields results in less than 10 minutes. That becomes an issue at processing plants as milk tankers line up bumper to bumper waiting to unload.
NCIMS delegates voted to establish a pilot program to look at the feasibility of testing up to seven additional antibiotics, says John Allan, vice president of regulatory affairs and international standards with the International Dairy Foods Association. The new testing protocols could likely require that no less than one in seven tankers to be tested for sulfonamides and no less than one in 15 tankers be tested for other six drugs. Because the frequency of Beta-lactams residues is so low, the frequency of testing Beta-lactams could be reduced.
Because FDA has not established safe or tolerance levels for some of the drugs to be tested, the agency will first need to establish “target test levels” for each, explains Pat Gorden, an Iowa State University veterinarian. He represents both the American Veterinary Medical Association and the American Association of Bovine Practitioners at NCIMS. Once those target test levels are established, drug test kit manufacturers can develop tests that are sensitive to those levels. It’s likely test kit development, training and sampling protocols won’t be available until next year.
But no firm timelines for additional testing have been set. The NCIMS committee which deals with antibiotic testing is to report back to the entire Conference in 2017 with any concerns.