Antibiotic residue testing in meat results in few positive samples

Meat is tested for antibiotic residue as part of the U.S. National Residue Program.

Meat, poultry and egg products are tested through the U.S. National Residue Program for the presence of more than 100 compounds. Meat and poultry products have been tested since 1967 and testing of egg products started in 1995. There are established tolerance levels determined through extensive research specific for each compound that determine what, if any, residual level is safe. That means many compounds have a zero tolerance as their established tolerance level, while others have been found to be safe at very low levels. The program has the interest of public health and safety in mind as well as preventing adulterated or misbranded products from being sold. Chemicals included in testing are antibiotics, sulfonamides, other approved and non-approved drugs, pesticides and environmental chemicals.

Part of the testing program includes scheduled sampling where random samples are taken from each production class (beef cows, bob veal, dairy cows, steers, heifers, market hogs, sows, young chickens, young turkeys) for various compounds of chemicals, including drugs. The number of scheduled samples for each production class is determined by previous findings and identification of compounds that have a food safety concern. There is also targeted sampling of animals that occur at the determination of USDA inspectors based on signs of disease, producer history, or results from scheduled sampling. The number of inspector-generated samples is 11.5 times greater than the random scheduled sampling, as every animal that is suspected by a USDA Inspector to have a residue is tested.

Sampling of meat products is done in the processing plant and swab tests are used to quickly determine initial positive or negative results. Samples are typically taken from the kidney or liver, as these are edible organ meats and areas where most compounds accumulate in at the highest levels before leaving the animal.

Overall, extremely low levels of positive samples are found to have residue violations. Scheduled and targeted samples combined were found to have 0.8 percent in violation (1,632 positives from 211,733 samples tested) according to data published by USDA Food Safety Inspection Service (FSIS) in 2010. There were 23 positive violations out of 18,374 tested scheduled samples (0.13 percent) for all production classes in 2010. For inspector-generated samples, Bob veal (1.2 percent), dairy cows (0.7 percent), and beef cows (0.5 percent) had the highest rate of violations. Direct extrapolation of these numbers cannot be made to the total population of animals harvested, as all animals suspected to have a residue are tested.

When a violation is found with in-plant rapid testing, samples are sent for laboratory confirmation including identifying and determining the level of the chemical(s) present. Carcasses from samples that come back positive are condemned and do not enter the food chain. The Food and Safety Inspection Service notifies the processing plant that in turn notifies the producer. Information is shared with the FDA (and subsequent state agencies such as the Michigan Department of Agriculture & Rural Development) or Environmental Protection Agency as these agencies have on-farm jurisdiction.

Corrective actions through education typically occur with producers at the first violation, but legal action may result. The meat from carcasses testing positive are held until confirmation and not allowed to be sold if they are found to be in violation. Producers with repeat violations, two or more violations in a 12 month period, are listed on the Residue Repeat Violator List. There is public access to this list and it is mostly used by inspectors, livestock markets and meat packing establishments.

Michigan State University Extension educators encourage producers to use antimicrobials judiciously, record all treatments, and follow required withdrawal periods to avoid marketing animals that may contain violating residues.