By: Marie Spano, MS, RD

Many consumers have questions about antibiotics and hormones in dairy products. While it's natural to question whether or not antibiotic and hormone used in dairy cows is contributing to the obesity epidemic, early puberty and antibiotic resistance, first we have to ask if these practices lead to any antibiotics or hormones in dairy products.

In this blog post I will cover:
- Antibiotics in dairy products
- Hormones in dairy products

Antibiotics are used on farms to treat animals that are sick just like you would give an antibiotic to your child if he or she is sick or take one yourself. Dairy farmers have no incentive to arbitrarily treat cows with antibiotics. Doing so costs additional money and serves no clear purpose. Now imagine you are a farmer and your life depends on the health of your cows – would you want to run the risk of antibiotic resistance and your cows getting sick with fewer treatment options?

Antibiotics are Not in Milk. Here’s Why:
Any cow that gets an antibiotic is milked separately from the rest of the herd and the milk is thrown out. That milk will never be sold or consumed. All antibiotics have a different period of time before all traces of the medication leaves the body (whether we are talking about a cow or a human). Once this period is up and the cow is completely healthy again, the farmer tests her milk. Milk cannot be sold until it is completely clear of all drug residues. Whether organic or conventional, all milk is tested several times before making it to market. It is tested on the farm and at the milk processing plant. Any milk that tests positive for any medication residue, including antibiotics, is thrown out. If antibiotics are not in milk they’re also not in cheese or yogurt as both are made from milk.

According to national Milk Drug Residue Database compiled for the years 2013 to 2014, 0% of milk tested positive for drug residues.

In 2015, the FDA’s Center of Veterinary Medicine surveyed 1,918 raw milk samples (before pasteurization) from across the country. Samples were tested for residues of 31 drugs including the antibiotics, NSAIDs (ibuprofen etc.) and an antihistamine. They found 99% of sampled milk was free of any drug residues.

New FDA Regulation
The FDA is phasing out antibiotics used for animal growth. Medically important, antimicrobial drugs (antibiotics) will no longer be allowed to enhance growth or feed efficiency. In the future, antibiotics will only be allowed to treat, control or prevent disease and of course require a prescription from a licensed veterinarian. Regardless of whether or not the antibiotic is used for growth or treatment of disease, no traces of antibiotic residues are allowed in milk or dairy products.

USDA organic dairy products are “produced without antibiotics fed or administered to the animal at any point in its life” (2). There are no meaningful nutrition differences in organic and conventional dairy products. I covered that topic in this post.

Growth Hormones
Growth hormones are approved for use in dairy cows to improve milk production. Greater milk production means fewer environmental resources used to raise cows for milk. Bovine somatotropin (also called bovine growth hormone or rBGH) is perhaps the most well recognized growth hormone used on dairy farms. bST is “a protein hormone produced in the pituitary gland of animals, including humans, and is essential for normal growth, development, and health maintenance.” Very little bST is used in dairy cows and there is no test that can distinguish between cows treated with bST and naturally occurring bST (3). Humans do not have receptors for bST and therefore it is passed through your body intact without being absorbed (4). As a result, there are no known side effects or health issues associated with consuming dairy from cows treated with bST. IGF-1 (insulin like growth factor 1) concentrations are slightly higher in cows treated with bST. However, the human body synthesizes IGF-I and drinking 1.5 L of milk is equivalent to an estimated 0.09% of the IGF-I produced by adults each day (5, 6, 7, 8).

What are the Cows Eating?
Cows’ diets also vary depending on many of the same factors that influence your food choices. However, unlike humans, all cows have the benefit of seeing a nutrition expert (like dietitians, animal nutrition experts are specialists). Many consumers also have questions about how cows are fed. Cows are fed nutritious diet to ensure health of cow and nutrition of milk. Typical feed mixtures may include haylage (grass with a higher water content), corn silage, sugar beet pulp and a protein mineral mix.

Rest assured, your dairy products are safe. In fact, the dairy product that says it is made with cows not treated with antibiotics is the exact same as the one from a cow that may have been treated with antibiotics. Both contain no antibiotic residues. Growth hormones used in dairy also pose no known threat to human health. The human body does not even recognize the main hormone used in cows. So, regardless of what milk, yogurt, or cheese you choose, all have been produced and extensively tested to ensure they are safe for human consumption.

References (if not cited via a hyperlink in the text of this post):
1. NATIONAL MILK DRUG RESIDUE DATA BASE FISCAL YEAR 2014 ANNUAL REPORT October 1, 2013 - September 30, 2014 http://www.fda.gov/downloads/food/guidanceregulation/guidancedocumentsregulatoryinformation/milk/ucm434757.pdf
2. Stacy Sneeringer, James MacDonald, Nigel Key, William McBride, and Ken Mathews. Economics of Antibiotic Use in U.S. Livestock Production, ERR-200, U.S. Department of Agriculture, Economic Research Service, November 2015. http://www.ers.usda.gov/media/1950577/err200.pdf
4. Bovine Somatotropin. National Institutes of Health, Techonology Assessment Conference Statement. December 5-7, 1990
https://consensus.nih.gov/1990/1990BovineSomatotropinta007html.htm
5. Joint FAO/WHO Expert Committee on Food Additives (JECFA). 1998. Toxicological evaluation of certain veterinary drug residues in food; Summary and conclusions. 50th report of the Joint FAO/WHO Expert Committee on Food Additives. World Health Organization, Geneva, Switzerland.
6. Collier RJ, Bauman DE. Update on human health concerns of recombinant bovine somatotropin use in dairy cows. J Animal Sci 2013; 92(4): 1800 – 1807. https://www.animalsciencepublications.org/publications/jas/articles/92/4/1800
8. Report on the Food and Drug Administration's Review of the Safety of Recombinant Bovine Somatotropin. Food and Drug Administration. http://www.fda.gov/animalveterinary/safetyhealth/productsafetyinformation/ucm130321.htm

This post was written as part of my ongoing sponsored partnership with U.S. Farmers & Ranchers Alliance. All opinions expressed are my own.

To read the full blog post and more from Marie, visit http://www.mariespano.com/.