Milk Vocabulary - A Glossary of Terms | a2 Milk® USA

Milk Vocabulary
A Glossary of Terms

When you buy your milk, you look for specific features based on your health or household needs. You pay attention to milk fat percentage, flavor, and where the milk is from – but what about all that other information on the carton. Do you know what the rest of those terms actually mean?

Below we’ve listed out a few common milk vocabulary terms as well as their definitions as they relate to purchasing and consuming milk products.


Medications that kill or slow the growth of harmful bacteria. Farmers may choose to treat cows that are ill with antibiotics. Milk from a cow being treated with antibiotics is separated to ensure that it does not enter the milk supply.

No milk, including a2 Milk®, sold in grocery stores contains antibiotics.



An essential nutrient for building strong bones and teeth. Milk is one of the best food sources of calcium in the American diet. 1 cup of milk provides 1/3 of the daily recommendation of 300mg of calcium.



The dominant protein family in cows’ milk.  Casein makes up 80% of the milk protein. There are several types of casein in milk including alpha, beta and kappa caseins.

At The a2 Milk Company, we focus on the milk’s beta-casein content by ensuring that our cows only produce the A2 beta-casein protein and no A1 type.


Grass Fed Milk

There is no accepted definition of the term grass-fed milk.


Growth Hormone, rBGH or rbST

bST (bovine somatotropin) is a protein hormone that occurs naturally in all dairy cows. Some farmers choose to supplement some of their cows with the growth hormone called rbST, also known as bovine growth hormone (rBGH), to help increase milk production. The safety of milk from rBST supplemented cows has been affirmed and reaffirmed since it was approved for use in the U.S. in the early 1990s.

a2 Milk® comes from cows that have NOT been treated with growth hormones.



A process applied to milk that breaks fat into smaller particles.  This process keeps the fat from separating and makes for smooth, consistent milk.


Lactose Free Milk 

Milk that contains less than 0.5g lactose per serving.


Organic Milk 

Milk that comes from farms meeting the USDA’s National Organic Program standards, which outline certain farming practices.



The industry standard method to kill potentially harmful bacteria found in raw milk, through heat treatment, without affecting the taste or nutritional value of milk. The process was named after its inventor, French scientist Louis Pasteur.

The most common form of dairy pasteurization is called High Temperature/Short Time (HTST). On milk packages, it is labeled, “Pasteurized” and it will last in the refrigerator for about two or three weeks from the date it was processed.  All milk is best if used within 7 days of opening the carton.

a2 Milk® is Ultra Pasteurized which means it is heated to a higher temperature than regular pasteurization for just a few seconds and then cooled very quickly. This creates an extended shelf-life and it will last in the refrigerator for six weeks or longer from the processing date.  Like other milks, a2 Milk® is best if used within 7 days of opening the carton.


Raw Milk 

Milk that has not been pasteurized before consumption.


Ultra-filtered Milk 

Milk that has been passed under pressure thought a thin, porous membrane to separate the components of milk according to their size and allows for some of the components to be concentrated.


Vitamin A 

A fat-soluble vitamin that helps form and maintain healthy eyes, teeth, muscles, and immune systems. Some of the vitamin A is taken out when fat is removed from milk (for instance in 1% low fat or 2% reduced fat milk). Most milk manufacturers add Vitamin A  back into the milk to make sure you’re getting the whole nutrient package, even if you choose reduced fat versions.

Vitamin A Palmitate  

A synthetic source of vitamin A used to fortify many dairy foods and breakfast cereals.


Vitamin D 

A fat-soluble vitamin that helps forms healthy bones, teeth and skin. Vitamin D is necessary for your body to absorb calcium which is also involved in the formation and maintenance of bones, teeth and skin. Because milk is one of the best food sources of calcium, Vitamin D is added to milk. In the early 1900’s, rickets, a childhood bone disorder that can lead to wear and soft bones and stunted growth was rampant in the US. The cause was Vitamin D deficiency. Because milk was found in almost every home in America, public health officials recommended adding Vitamin D to milk. In the 1930’s, the dairy industry started adding vitamin D to milk and it has ever since.



 The second most abundant protein type found in cows’ milk (about 20% of the total protein content).



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