What's the Difference Between Organic and Regular Milk?

The demand for organic food has increased over the years. More people choose organic food, such as organic milk, for various reasons, including health, the environment and animal welfare. According to the Organic Trade Association (OTA), organic food sales in 2023 surpassed $63 billion in the United States. Organic dairy products and eggs came in second place for organic food sales behind organic produce.

So, what is the difference between organic milk and regular milk? Is organic milk better? Should you choose organic milk over conventional milk? Let's take a deep dive to explore their similarities and differences from an agricultural and nutritional perspective.

Organic Milk vs. Regular Milk: What's the Difference?

Organic milk and regular milk—also known as conventional milk—have some similarities and differences. The stark difference between the two types of milk lies in the agricultural practices used in milk production.

In the U.S., conventional farmers may use pesticides to control the growth of weeds with their crops. Cattle farmers could also use synthetic bovine growth hormone (BGH), also known as bovine somatotropin (BST), a Food and Drug Administration (FDA)-approved drug to increase milk production, and antibiotics to reduce the risk of infection in cattle when needed.

On the other hand, organic milk producers must abide by the USDA organic guidelines. According to the standards, cattle farmers who want to produce organic milk must manage their herd as organic for at least one year before milk production. The cows must be fed with certified organic feed and are not allowed to be injected with growth hormones or given antibiotics.

Is Conventional Milk Safe to Consume?

Because pesticides, synthetic growth hormones and antibiotics may be used in conventional milk production, residues of these substances could potentially be present in the milk sold to consumers. Some research, like a 2019 study in Public Health Nutrition, suggests that dairy cows injected with synthetic growth hormones may raise humans' insulin-like growth-factor-1 level (IGF-1).

Under normal circumstances, IGF-1 is a growth hormone promoting bone and tissue growth and development. However, several studies, including a 2020 review in the European Journal of Nutrition, note that increased levels of IGF-1 might increase one's risk for colorectal, prostate and breast cancers.

Dairy cattle injected with synthetic growth hormones may also be more prone to infections, increasing their need for antibiotics. This may raise conventional milk consumers' risk of greater exposure to antibiotics and antibiotic resistance, per the same 2019 study in Public Health Nutrition.

While consuming conventional milk may pose some health risks for certain individuals, the evidence is mixed and more research is needed to determine their long-term health effects.

That said, conventional milk is still safe to consume. This is, in large part, thanks to the FDA, which sets limits on the amount of trace antibiotics that could be present. The FDA also works closely with the USDA's Food Safety and Inspection Service and state regulators to ensure unapproved and unsafe drugs are not used for milk production.

According to the study in Public Health Nutrition, organic milk is free of pesticides, synthetic hormones and antibiotics due to the farming standards farmers must adhere to. You can also be assured that the organic milk you purchased is truly organic by seeing the USDA green-and-white certified organic symbol on the packaging.

Nutritional Differences Between Conventional and Organic Milk

According to the USDA, both conventional milk and organic milk provide 16 essential nutrients, including protein, calcium, phosphorus, vitamin A, vitamin B12 and vitamin D, making them highly nutritious.

And while both types of milk have similar nutrition profiles, some studies, like a 2021 study in the journal Foods, suggest organic milk has higher levels of healthy fats, including omega-3 and polyunsaturated fats. The higher amount of healthy fats present is, in part, due to the feed provided by the farmers.

This same study found that organic milk has higher concentrations of conjugated linoleic acid (CLA). CLA is a type of fat found in dairy and beef that may be associated with supporting a healthy immune system and reducing the risk of heart disease, cancer, obesity and osteoporosis, according to a 2019 review in Nutrients.

Organic farmers also offer more fresh forage to the cattle and allow them to graze. Feeding dairy cows with fresh forage and allowing them to graze may be one of the reasons for organic milk having a more favorable fatty acid composition than conventional milk. This is because eating a variety of plants increases the number of different nutrients they consume. This is then passed on to their milk (and meat).

The same 2021 Foods study suggests that the season of the year during milk production may also contribute to the varying levels of fatty acid present between regular milk and organic milk, despite the type of farming method used.

So, is organic milk better for you?

While there are some studies about the differences between organic and conventional milk, more research is needed to clarify their long-term effects on health. The greater amount of fatty acids present in organic milk is not convincing enough for the scientific community to recommend choosing organic milk over conventional milk.

Why Does Organic Milk Last Longer?

While organic milk and regular milk have similar nutrition and serve the same purpose, organic milk may last substantially longer than conventional milk if it undergoes a process called "ultra-pasteurization" where it is heated to 280°F for 2 seconds, rather than 161°F for 15 seconds like conventional milk, per the International Dairy Foods Association (IDFA). However, some brands of conventional milk also undergo ultra-pasteurization. Check the label to be sure.

Ultra-pasteurization allows organic milk or conventional milk to last for 40 to 60 days after opening, compared to 15 to 17 days for milk that is pasteurized at a lower temperature. That said, milk generally tastes best between seven and 10 days after opening and when held in a refrigerator at 40˚F. So, if you run into problems with your milk going bad before you can finish it, ultra-pasteurized milk might be something worth trying. Or you can buy smaller cartons of milk.

Choosing Organic vs. Conventional Milk

What type of milk you buy is ultimately a personal choice. You may lean toward choosing organic food over its conventional counterparts for various reasons.

Organic dairy farmers must follow strict regulations about what they can give to their cows. If you are concerned about being potentially exposed to trace amounts of pesticides, antibiotics and synthetic growth hormones in conventional milk, you may want to consider organic milk.

Food products that are produced organically require a bigger time commitment and financial investment from the farmers and producers. For that reason, organic foods are generally pricier than conventional choices. If you are on a budget, conventional milk might be a better choice. Since milk is a nutritious and affordable food, choosing conventional milk is better than avoiding milk altogether if you can't justify buying organic.

From a registered dietitian's perspective, both conventional milk and organic milk are highly nutritious and can be a healthy part of your diet.

The Bottom Line

The main difference between organic and conventional milk is in the way that milk is produced. Both organic milk and conventional milk are nutritious, provide similar nutritional qualities and can be part of a healthy meal pattern. Whether you choose organic milk or conventional milk is a personal preference. While there are some studies about the differences between organic and conventional milk, more research is needed to clarify their long-term effects on health.