Manure used in agriculture can contain antibiotic residues
Crops are sometimes fertilized with manure that could contain antibiotic residues.
Do residues in food directly harm humans?
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.
What do tests show about antibiotics in foods
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.
Residues in water supply
Antibiotics from human and agricultural waste can remain in public water systems even after processing.
Antibiotics are used primarily in animal husbandry
Between 70% and 80% of antibiotic sales in the United States go to livestock rather than humans.