Many everyday foods can contain trace amounts of antibiotics, not because they’re added at the grocery store, but because antibiotics are widely used in the animals and crops that become your food. Globally, an estimated 81,000 to 89,000 tonnes of antibiotics are used in food-producing animals each year. These drugs show up most often in meat, dairy, seafood, eggs, and honey, with smaller amounts used on certain fruit crops.
Meat and Poultry
Meat is the biggest source of dietary antibiotic exposure. Livestock producers use antibiotics to prevent disease in crowded conditions and, in some countries, to promote faster growth. Roughly 88% of growing pigs in the U.S. receive antibiotics in their feed, most commonly tetracyclines. Poultry operations rely heavily on the same drug class, along with sulfonamides and quinolones.
Residues are measurable in the muscle, liver, and kidney tissue of treated animals. Testing in several countries has found tetracycline concentrations in chicken breast ranging from 124 to over 5,800 micrograms per kilogram, with even higher levels in organ meats like liver. Beef samples show a similar pattern, though generally at lower concentrations. The concern isn’t a single meal but the cumulative, low-level exposure over years of eating conventionally raised meat.
Dairy and Eggs
Dairy cows are routinely treated with antibiotics for udder infections, and residues can pass into milk. The most commonly detected drug family in U.S. milk is beta-lactams (the penicillin family), which accounted for 558 out of 567 positive tests in nearly 4 million samples analyzed by the FDA in 2019. The good news: the overall positive rate for bulk milk tankers was just 0.009%, meaning the screening system catches most contaminated batches before they reach consumers.
Eggs are a different story. A study from China found that 30% of egg samples tested positive for quinolones, tetracyclines, or sulfonamides. Regulatory oversight for eggs varies significantly by country, and residue rates in regions with less rigorous testing tend to be higher.
Farmed Seafood
Aquaculture is a major user of antibiotics worldwide. Farmed salmon, shrimp, and tilapia are the species most likely to carry residues. In Canadian salmon farming, oxytetracycline has historically dominated antibiotic use, at one point accounting for 84% of all antimicrobial volume in a single production year. Other drugs used in fish farming include florfenicol and sulfonamide combinations.
Usage varies enormously by country. Norwegian salmon farming uses far less than operations in Canada or Chile, and some Southeast Asian shrimp farms use antibiotics with little regulatory oversight. Imported farmed seafood generally carries more risk of residues than domestic products in countries with stricter controls.
Honey
Beekeepers use antibiotics to control bacterial diseases that can devastate hives. Oxytetracycline has been the go-to treatment since the 1950s, though streptomycin, sulfonamides, erythromycin, and tylosin are also common depending on the country. These drugs end up in the honey itself at detectable levels.
Testing of commercial honey has found tetracycline residues ranging from less than 1 microgram per kilogram up to 232 micrograms per kilogram. Streptomycin has been detected at 35 to 117 micrograms per kilogram, and quinolones at 1.4 to 41 micrograms per kilogram. The European Union sets regulatory limits for many of these compounds in honey (for example, 10 micrograms per kilogram for tetracyclines), but not all producing countries enforce the same standards. The EU bans certain antibiotics in beekeeping entirely, while the U.S. and many other countries still permit them.
Fruits and Vegetables
Antibiotics in produce are less common but not zero. The U.S. Environmental Protection Agency approved oxytetracycline and streptomycin for use on citrus trees to combat citrus greening disease, a bacterial infection threatening the Florida orange industry. This decision overrode objections from both the CDC and the FDA, which raised concerns about fueling antibiotic resistance. Streptomycin has also been used for decades on apple and pear trees to prevent fire blight, a bacterial infection that kills branches and fruit.
Residues on fruit skins from these spray treatments are generally low, but the broader concern is environmental. Antibiotics sprayed on orchards can enter soil and waterways, creating conditions where resistant bacteria develop outside of any medical setting.
Processed and Cooked Foods
If you’re wondering whether cooking or processing eliminates antibiotic residues, the answer is: not reliably. There is surprisingly little research on how antibiotics break down during curing, smoking, canning, or fermentation. What is known suggests that some residues survive standard cooking temperatures, and their breakdown products aren’t always well studied for safety. One study found that residual antibiotics in meat can actually disrupt the fermentation process used to make products like salami, altering the bacterial cultures that are supposed to make the food safe.
This means processed meats like sausages, deli cuts, and canned products made from conventionally raised animals may still carry residues from the source meat.
How Low-Level Exposure Affects Your Body
The amounts in any single food item are small, well below a therapeutic dose. But research suggests that even these trace exposures matter over time. In mouse studies, daily intake of antibiotic residues at levels considered safe by regulators altered gut bacteria composition in ways linked to metabolic problems. Beneficial bacteria decreased while bacteria associated with obesity and inflammation increased.
The timing of exposure also matters. Animals exposed to antibiotic residues early in life lost certain beneficial gut bacteria permanently, and those losses were associated with metabolic dysfunction in adulthood, even after the antibiotic exposure stopped. Diet was the strongest overall factor shaping the gut microbiome, but antibiotic residues acted as a secondary force, shifting bacterial populations in a dose-dependent way.
Beyond gut health, penicillin residues in pork and beef have been linked to allergic reactions in sensitive individuals, including anaphylaxis in people with penicillin allergies who consumed meat with residue levels above safety thresholds.
How to Reduce Your Exposure
Labels are your most practical tool. USDA Certified Organic meat requires that animals were never administered antibiotics at any point in their lives and were fed 100% organic feed. The “No Antibiotics Ever” label carries a similar claim, though it relies on producer attestation rather than the full organic certification process. Either label meaningfully reduces your exposure compared to conventional products.
For seafood, wild-caught fish don’t receive antibiotics. If you buy farmed fish, look for certifications that restrict antibiotic use, or choose species and origins known for lower usage (Norwegian farmed salmon, for instance, uses very little). For honey, European-sourced honey tends to meet stricter antibiotic standards than honey from Asia or South America.
Peeling fruit removes surface residues from antibiotic sprays, though this is a minor source of exposure compared to animal products. The biggest single step you can take is choosing antibiotic-free meat and dairy, since these account for the vast majority of dietary antibiotic exposure.