What’s In Your Milk? It’s Not What You Might Have Heard

Psst, I have a secret to tell you. Your milk is full of something. They are small, there’s a lot of them, and they affect your health. Want to know what it is?

It’s nutrients! Good ol’ Vitamin A, Vitamin D, Calcium, Protein, Phosphorus, Magnesium, Vitamin B12, Folate, Zinc, and a bunch more. Wow, I feel so much better getting that out there.

Lately, or should I say “again”, the safety of milk is being brought into question. Specifically, the claim that milk sold to consumers contains hormones and antibiotics. I’m going to take some time explaining these claims, but here’s the spoiler: 1) there are no antibiotics in milk for several (potentially expensive) reasons, and 2) there are no hormones in the milk we consume. I’m not saying they don’t exist, I”m just saying they aren’t causing what is being claimed.

Hormones in Milk

All milk contains naturally-occurring hormones, one of which is bovine somatotropin (BST), aka bovine growth hormone (BGH), which helps cows produce milk. rBST is the synthetic form of BST and was approved in the 1990’s to be given to dairy cows to help boost milk production. BST nor rBST make the cow or calf grow faster. While hormones in the milk help the calf develop, the calf’s own growth hormone has more of an effect.

This hormone is species-specific, meaning it does not do anything in humans. Studies done on BST and rBST indicate that it will not survive human digestion and is actually broken down because it’s an amino acid, nor does it have an effect on human growth hormone receptors. In fact, 90% of BST is killed during pasteurization; the rest is digested.

Milk from cows treated with rBST vs. those who are not treated have the same nutritional quality and safety. Some processors choose to not use rBST and label their products as such, but this is more for advertising preference to influence consumer perception.

What about milk causing early puberty in girls? It is true that girls today are entering puberty earlier, but there may be several reasons. One theory is the rise in obesity, which has been increasing in kids as well as adults. Puberty tends to occur earlier in girls who are heavier. The claim that hormones in milk is responsible is not supported for several reasons: 1) Kids who drink milk regularly tend to be of more normal weight, 2) Today’s kids drink less milk than their parents did, and 3) rBST is cow-specific and does not have an effect on human growth hormone.

Antibiotics in Milk

I wrote earlier that there are expensive reasons why antibiotics are not in the milk we consume. The USDA and FDA have strict regulations for the use of antibiotics to treat animals. It is true that antibiotics are given to cows, but only when needed to treat infections such as mastitis. This is an inflammation of the mammary glands and udder tissue, causes decreased milk production, and effects the quality and safety of milk.

If and when antibiotics are given to cows, there are strict withdrawal times to which producers have to adhere before they can sell the milk. Different antibiotics have different withdrawal times – the time that it takes for the antibiotic to be out of the cow’s system. Per regulation, every tanker of milk is tested for antibiotics. If any amount is found, that entire tank is disposed of and farm samples are taken to find the source, all at the producer’s expense. Regulatory action is taken for positive test results. States can impose additional penalties such as fines and license revocation. Simply put, any milk that tests positive for antibiotics, whether it’s organic, rBST-free, or conventional cannot be sold to the public

By the way, this regulation also applies to meat cows, but this is an article for another day. But let me give the ending away anyway- there are no antibiotics present in the beef we consume, or any meat for that matter.

I hope that this article helps explain some of the misconceptions that may be floating around about the quality and safety of milk. Producers take great care to ensure that the milk they sell is of high quality, safe to consume, and does not pose a threat to human health. Not only would it be financially costly, but it can destroy public confidence and trust in the company or producer. And that alone is much harder to get back.


Posted: February 20, 2019

Category: Agriculture, Food Safety, Health & Nutrition, WORK & LIFE
Tags: Milk Quality, Milk Safety

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