Antibiotics in Foods: Everything You Need to Know

Because large amounts of antibiotics are harmful and some people are allergic, the FDA inspects all commercial meat, eggs, and dairy to ensure that they contain no antibiotic residues.

All food-producing livestock that were administered antibiotics undergo a mandatory withdrawal period so that the antibiotics can clear their system before they are slaughtered or reintroduced to the dairy or egg production line.

In 2017 the FDA banned the use of medically important antibiotics — those also used to treat humans — in animal feed for the purposes of growth promotion and feed efficiency. The ban came as certain bacteria have become increasingly resistant to antibiotics.

Antibiotics are routinely sprayed on some fruit and vegetable crops as a pesticide. About 16% of apple acreage and 40% of pear acreage is sprayed every year, though the trees are only sprayed when the blossoms appear and not while there is fruit on the branches.

Around 1950, after scientists discovered that animals fed antibiotics gained weight faster, farmers began using sub-therapeutic doses of antibiotics in animal feed to promote growth and increase the efficiency of their feed. This practice, however, has now been largely banned.

Beekeepers sometimes use antibiotics in their hives. The regulations on honey are not very strict in the United States and also vary from country to country. As honey is often imported, it can contain antibiotic residues.

Crops are sometimes fertilized with manure that could contain antibiotic residues.

Antibiotics in food and water sources could affect human gut flora by killing beneficial bacteria, but there are very few studies demonstrating what amount of residues in food might be harmful to the human gut microbiome. Antibiotics residue is of more serious concern to people who are allergic to antibiotics and could have an anaphylactic reaction.

In 2010, FDA testing of animal food products revealed that 2% contained antibiotic residues, and only 0.1% had residue levels in violation of federal standards. Violations were most common in veal cows, turkeys, and rabbits. Following the 2017 ban, it is possible residue levels have changed.

Antibiotics from human and agricultural waste can remain in public water systems even after processing.

Between 70% and 80% of antibiotic sales in the United States go to livestock rather than humans.

Before the new regulations in 2017, sales of medically important antibiotics for use in food animals were already decreasing. They dropped 33% between 2016 and 2017.

Organic milk comes from cows never treated with antibiotics. If an organic milk cow gets sick enough to require antibiotic treatment, its milk may no longer be used by the organic farm. The cow is usually treated and then permanently removed from the organic herd.

Despite regulations and testing, antibiotic residues may still exist in some foods. A June 2019 study of purchased half-gallons of milk published by Cambridge University Press showed that of the organic milk samples tested, none contained traces of antibiotics. But 26%-60% of the conventional milk samples purchased tested positive for various antibiotics, including drugs that have been prohibited for use in dairy cows. Several samples showed residue levels above federal limits.

In 1996, the National Antimicrobial Resistance Monitoring System (NARMS) was established. NARMS tracks changes in bacteria, specifically related to antimicrobial resistance, in meats, food-producing livestock, and humans.

Although farmers can no longer feed their livestock antibiotics for growth promotion, they can still feed them preventive doses to counter the illnesses that are common in close living quarters, such as feedlots.

Sales of antibiotic-free meat grew by almost 29% every year between 2011 and 2015.

Federal Veterinary Feed Directive (VFD) rules established by the FDA in 2017 require farmers to have a written prescription when administering medically-important antibiotics to their livestock. The VFD rules do not apply to antibiotics that are not considered medically important.

The 2017 FDA restrictions on the use of medically important antibiotics in animal feed were enacted by requesting that drug manufacturers voluntarily relabel their antibiotics, removing growth or feed efficiency from the approved uses, effectively making the use of antibiotics for those purposes illegal.

In 2010, the FDA published its first ever report estimating the amount of antibiotics sold for use in food-producing livestock. The estimate: nearly 29 million pounds.

According to the FDA’s 2018 Residue Sample Results, the top three antibiotics found in animal food product samples whose residue levels violated federal standards were ceftiofur, penicillin, and sulfadimethoxine. Of the three, only Penicillin is used in humans.

Although organic meats are raised without the use of antibiotics, some studies have shown that organic chicken can contain higher levels of bacteria such as Salmonella, Campylobacter, and Enterococcus. All of these bacteria can be killed by proper cooking, but not sanitized surfaces and dishes may still spread the bacteria.

From 1994 to 2015, the amount of milk samples evaluated by the FDA containing beta-lactam antibiotics — the most common drugs used on dairy farms — fell from 0.15% to 0.014%.

Ionophores are a class of antibiotics that is considered non-therapeutic and is not used in human medicine. Used solely as feed additives to increase the efficiency of animal digestion, ionophores are considered a safe alternative to medically important antibiotics because they have not been shown to contribute to the development of antimicrobial resistant bacteria.