Milk—it does a body good… so long as it does not contain antibiotics that are not supposed to be there. While hogs, beef cattle, and chickens in meat production are approved for antibiotic treatments, lactating dairy cattle are not. The reason for this distinction is that antibiotics and their metabolic residues show up in the cows’ milk almost immediately, and the U.S. Food and Drug Administration says milk with these drugs and drug residues is not safe for human consumption.
Recently, the FDA conducted a double-blind survey of milk samples to determine whether farms with troubled pasts were turning out tainted milk. The agency tested milk samples from nearly 2,000 dairy farms, half of which were from a targeted group of farms with histories of violations, and the other half randomly selected to serve as safe controls. The farms that made the targeted list did so by previously sending cows to slaughter that tested positive for restricted drug residues in the meat.
The milk samples, which were collected in a blind, unidentifiable manner, were screened for the presence of 31 different drugs. A bit more than one percent of the targeted group samples tested for at least one drug or drug residue that was not supposed to be present. In comparison, only about 0.4 percent of the control group samples tested positive. Overall, residues of six drugs were found, the most common being residues of the antibiotic Florfenicol. None of the drugs found are approved for use in lactating dairy cattle.
Because of the nature of the study, no followup investigations of individual farms are pending. Deputy Director of Science Policy at the FDA’s Center for Veterinary Medicine William Flynn emphasized that, while the presence of any banned substances in milk and other dairy products is concerning, the overall picture shows that the number of violations is very low, indicating that current policies are working as intended.
According to Flynn, the FDA is continuing to develop new ways to eradicate illegal drug use by dairy farmers, including the expansion of testing arrays to include more drugs. The full report is available from FDA.gov.