Agriculture uses antibiotics to help reduce death rates among livestock, but the amount is very low and tightly regulated. No current evidence suggests that antibiotics in meat and animal foods directly harms humans.
The demand for food products raised without antibiotics is growing fast.
In 2012, sales of these products had increased by 25% over the previous 3 years (1).
The overuse of antibiotics in food-producing animals is being blamed for the increase in resistant bacteria, also known as “superbugs.”
When these are passed to humans, they can cause serious illness.
However, other experts suggest that antibiotic use in food-producing animals poses very little risk to human health.
This article explores how antibiotics are used in foods and their potential consequences for your health.
Antibiotics are drugs used to treat bacterial infections. They work by killing or stopping the growth of harmful bacteria.
Since the 1940s, antibiotics have been given to farm animals such as cows, pigs, and chickens in order to treat infections or prevent an illness from spreading.
Low doses of antibiotics are also added to animal feed to promote growth. This means a greater production of meat or milk in shorter periods of time (2).
These low doses may also reduce animal death rates and improve reproduction.
For these reasons, antibiotic use has become widespread in agriculture. However, from 2015–2018, sales of medically important antimicrobials for use in food-producing animals decreased by 38% (
Antibiotics are drugs used to treat bacterial infections. They are widely used in animal agriculture to treat disease and promote growth.
Contrary to what you may think, your chance of actually consuming antibiotics through animal foods is extremely low.
Strict legislation is currently in place in the United States to ensure that no contaminated food products enter the food supply. The National Residue Program (NRP) is administered by the U.S. Department of Agriculture (USDA) Food Safety and Inspection Service for this purpose (4).
Similar laws are in place in Canada, Australia, and the European Union.
Additionally, veterinarians and animal owners are required to ensure that any animal products they produce are drug-free before they can be used as food.
Drug withdrawal periods are enforced before treated animals, eggs, or milk are used as food. This allows time for the drugs to completely leave the animals’ systems.
The USDA has a strict process of testing all meat, poultry, eggs, and milk for unwanted compounds, including antibiotic residues (5).
As a result of strict government legislation, it’s extremely rare that antibiotics given to animals enter the food supply.
Antibiotic residues in food products have been associated with many health concerns.
According to some research, these residues may cause several serious side effects in humans, such as allergies, and may negatively affect the health of the liver, kidneys, reproductive system, and immune system (
For this reason, the Food and Drug Administration (FDA) has established strict regulations for the minimum amount of time allowed between the last dose of antibiotics administered to an animal and the time of slaughter (9).
These regulations are intended to help decrease the amounts of antibiotic residues in food products and thereby minimize the risk of potential health concerns.
Additionally, the NRP analyzes meat, egg, and poultry products for chemical contaminants to ensure that antibiotic residues within the food supply remain low (4).
Figures from the USDA show that the amounts of animal products found to have antibiotic residues is extremely low (10).
Products that test positive residues for antibiotics do not enter the food chain. Additionally, producers who repeatedly violate regulations are publicly exposed and added to a Residue Repeat Violators List, which is intended to discourage any misconduct (11).
The FDA strictly regulates residues from antibiotics. Figures from the USDA show that the amount of animal products found to have antibiotic residues is extremely low.
Antibiotics are generally fine when used properly for treating or preventing infections.
However, excessive or inappropriate use is a problem. When antibiotics are overused, they end up becoming less effective for both humans and animals.
This is because bacteria that are frequently exposed to antibiotics develop a resistance to them. As a result, the antibiotics are no longer as effective at killing harmful bacteria. This is a great concern for public health (
The FDA has recognized this concern, updating its regulations to reduce the unnecessary use of antibiotics in livestock (
Excessive antibiotic use can increase resistant bacteria, making the antibiotics less effective for both animals and humans.
Resistant bacteria can be passed from food-producing animals to humans in a number of ways.
If an animal is carrying resistant bacteria, the bacteria can be passed on through meat that is not handled or cooked properly (
You can also encounter these bacteria by consuming food crops that have been sprayed with fertilizers containing animal manure with resistant bacteria.
One 2013 study found that people living close to crop fields sprayed with pig manure fertilizer are at a higher risk of infection from the resistant bacteria MRSA (
Once spread to humans, resistant bacteria can stay in the human gut and spread between individuals. The consequences of consuming resistant bacteria include (
- infections that would not have happened otherwise
- increased severity of infections, often including vomiting and diarrhea
- difficulty in treating infections and higher chances that treatments will fail
In the United States, around 2.8 million people each year get infected with bacteria resistant to one or more of the antibiotics normally used to treat the infections (
Of those people, at least 35,000 die each year. Many more die from other conditions that have worsened as a result of these infections (
Resistant bacteria can be transferred from animals to humans through contaminated food products, causing infections and even death.
Resistant bacteria in supermarket foods are much more common than you might think.
Commonly reported harmful bacteria from foods include Salmonella, Campylobacter, and E. coli.
In a 2001 study of 200 U.S. supermarket samples of chicken, beef, turkey, and pork, 20% contained Salmonella. Of these, 84% were resistant to at least one antibiotic (
One report from 2011 found resistant bacteria in 81% of ground turkey meat, 69% of pork chops, 55% of ground beef, and 39% of chicken breasts, wings, and thighs in U.S. supermarkets (
In another 2011 study, researchers tested 136 beef, poultry, and pork samples from 36 U.S. supermarkets. Almost 25% tested positive for the resistant bacteria MRSA (
Many products claim to be “raised without antibiotics,” including some that are labeled “organic.” However, this does not mean these products are free from resistant bacteria.
Evidence suggests that these products still contain resistant bacteria, although they are slightly less resistant than those in products grown using antibiotics.
A 2005 study found that organic chickens were contaminated with bacteria such as Salmonella and Campylobacter more frequently than non-organic chickens. However, the bacteria in organic chickens were slightly less resistant to antibiotics (
In a different study, the prevalence of Enterococcus bacteria was 25% higher in organic chicken than non-organic chicken. However, the amount of resistant bacteria was almost 13% lower in organic chicken (
Another study found that out of 213 samples, the frequency of antibiotic-resistant E. coli tended to be only slightly lower in chicken raised without antibiotics than in regular chicken (
Resistant bacteria are often found in animal-based food products. Food labeled “organic” or “raised without antibiotics” may have slightly lower amounts of resistant bacteria.
There is no clear-cut evidence that humans can become infected with resistant bacteria from food.
If the food products are cooked properly and good hygiene practices are followed, then the risk is probably extremely low.
However, the human use of antibiotics may be the cause of most bacterial resistance (
Still, more research is needed to determine how serious a concern this is.
There is no clear-cut link between antibiotic use in animals and resistant bacteria infections in humans. The risk to human health is likely to be small, since adequate cooking destroys bacteria in food.
It may be impossible to completely avoid resistant bacteria in animal foods.
However, you can take some steps to significantly reduce your risk:
- Practice good food hygiene. Wash your hands, use separate cutting boards for different foods (especially for raw meat), and wash utensils thoroughly.
- Ensure food is cooked properly. Cooking meat to the proper temperature should kill any harmful bacteria.
- Buy antibiotic-free foods. You can minimize your risk even further by looking for labels that specify “organic,” “raised without antibiotics,” or “antibiotic-free.”
- Check for the USDA Process Verified label. This means USDA inspectors have visited the farm to verify antibiotic use (27).
The debate on antibiotic use in animals is ongoing.
Although there’s no evidence that antibiotics in foods harm people directly, most people agree that the overuse of antibiotics in food-producing animals is a problem.
It can contribute to the development and spread of drug-resistant bacteria, which is a potential risk to public health.