Types of Milk
There are many types of cows’ milk available on the market today to meet a wide range of consumer preferences and health concerns. The primary types of milk sold in stores are: whole milk, reduced-fat milk (2%), low-fat milk (1%), and fat-free milk. The percentages included in the names of the milk indicate how much fat is in the milk by weight.
Whole milk contains 3.5% milk fat. This is the amount of fat in milk when the cow is milked. Consumers that are concerned about calories and fat content have multiple options; reduced-fat milk contains 2% milk fat and low-fat milk contains 1% milk fat. Fat-free milk, also called nonfat or skim, contains no more than 0.2% milk fat. Reduced-fat, low-fat and fat-free milks contain all of the nutrients found in whole milk but less fat. The United States government sets minimum standards for fluid milk that is produced and sold. Reduced fat milks have all of the nutrients of full fat milk; no water is added to these types of milk. Check the Milk Nutrition page for a full listing of the nutrients in milk.
Milk Processing
Most milk undergoes processing after leaving the cow and before you buy it at the store. The three primary steps include: pasteurization, homogenization and fortification. Pasteurization requires heating the milk to destroy harmful microorganisms and prolong shelf life. Normal pasteurization keeps milk safer while maintaining its valuable nutrients. Ultra-high temperature (UHT) milk is pasteurized at a much higher temperature to make it sterile. UHT milk is then packed into special containers that keep it safe without requiring refrigeration. After pasteurization, milk undergoes homogenization to prevent separation of the milk fat from the fluid milk. Homogenization creates a smooth, uniform texture. Finally, milk is fortified to increase its nutritional value or to replace nutrients lost during processing. Vitamin D is added to most milk produced in the United States to facilitate the absorption of calcium. For more information about the health benefits of vitamin D, check out the handout Vitamin D: What You Need to Know About the Sunshine Vitamin. Vitamin A is frequently added to reduced-fat, low-fat and fat-free milks. Vitamin A promotes normal vision, particularly helping the eyes to adjust to low-light settings. Check the Nutrients in Milk page on our website for a complete listing of the key nutrients found in milk.
Organic Milk
All milk must comply with very stringent safety standards and is among the most highly regulated and safest foods available. Organic milk is produced by dairy farmers that use only organic fertilizers and organic pesticides, and their cows are not given supplemental hormones. Dairy farmers and producers make many specialty forms of milk to meet consumer preferences and needs. Organic milk is also available as lactose-free and ultra-pasteurized. Organic classification is not a judgment about the quality or safety of any product. As with all organic foods, it's the process that makes milk organic, not the final product. The nutrient content of organic milk is the same as standard milk and offers no additional health benefits compared to standard milk. Stringent government standards that include testing all types of milk for antibiotic and pesticide residues ensure that both organic milk and conventional milk are pure, safe and nutritious.1
rBST Free Milk
rBST-free milk, is another kind of milk available. rBST is a synthetic version of the natural hormone BST (bovine somatotropin). Some dairy farmers choose to give their cows rBST to help them increase milk production. In the early 1990s, after rigorous testing, the FDA approved the use of rBST in milk production and declared the milk from rBST-supplemented cows safe for human consumption. This has been affirmed and reaffirmed by the FDA, World Health Organization, American Medical Association, National Institute of Health and regulatory agencies in 30 countries. BST is species-specific, which means that it is biologically inactive in humans. In addition, pasteurization destroys 90% of BST and rBST in milk. The remaining trace amounts of this hormone in milk are broken down into inactive fragments (amino acids) by the gastrointestinal tract. Furthermore, studies linking the hormones in milk to the early onset of puberty are false; both hormones are "cow-specific," meaning they have no effect on the human body. Since the milk produced is identical and offers the same nutritional benefits,2 producers are not required to label whether or not their cows are treated with rBST; however, some producers that do not use rBST often market their milk as "rBST-free" Those still concerned can choose rBST-free versions of their milk and milk products.
1United States Department of Agriculture. Organic Production and Handling Standards. 2006. Retrieved 14 July 2008. http://www.ams.usda.gov.
2Vicini, John et al. Survey of Retail Milk Composition as Affected by Label Claims Regarding Farm-Management Practices. 2008. 1200-1202.