Fat Content of Milk



The fat content of milk is the proportion of milk made up by butterfat. The fat content, particularly of cow's milk, is modified to make a variety of products. The fat content of milk is usually stated on the container, and the colour of the label or milk bottle top varied to enable quick recognition.

Methods for changing fat content
To reduce the fat content of milk, e.g. for skimmed or semi-skimmed milk, all of the fat is removed and then the required quantity returned. The fat content of the milk produced by cows can also be altered, by selective breeding and genetic modification. For example, scientists in New Zealand have bred cows that produce skimmed milk (less than 1% fat content).

Methods of detecting fat content
Milk's fat content can be determined by experimental means, such as the Babcock test or Gerber Method. Before the Babcock test was created, dishonest milk dealers could adulterate milk to falsely indicate a higher fat content. In 1911, the American Dairy Science Association's Committee on Official Methods of Testing Milk and Cream for Butterfat met in Washington DC with the U.S. Bureau of Dairying, the  U.S. Bureau of Standards and manufacturers of glassware. Standard specifications for the Babcock methodology and equipment were published as a result of this meeting. Improvements to the Babcock test have continued.

Terms for fat content by country
The terminology for different types of milk, and the regulations regarding labelling, varies by country and region.

Canada
In Canada "whole" milk refers to creamline (unhomogenized) milk. "Homogenized" milk refers to milk which is 3.25% butterfat. Generally all store-bought milk in Canada has been homogenized. Yet, the term is also used as a name to describe butterfat content for a specific variety of milk. Modern commercial dairy processing techniques involve first removing all of the butterfat, and then adding back the appropriate amount depending on which product is being produced on that particular line. In Canada homogenized milk is also marketed as "homo milk," a curious label that befuddles giggling American tourists. ( e.g. http://www.beatrice.ca/products/index.asp?section=milk)

In the U.S. and Canada, a blended mixture of half cream and half milk is often sold in small quantities and is called half-and-half. Half-and-half is used for creaming coffee and similar uses. In Canada, low-fat cream is available, which has half the fat content of half-and-half.

United States
In the USA, skimmed milk is also known as "fat free" milk, due to USDA regulations stating that any food with less than ½ gram of fat per serving can be labelled "fat free".

United Kingdom
Three main varieties of milk by fat content are sold in the UK, skimmed, semi-skimmed and whole milk. These make up 17%, 58% and 25% of the market respectively. Until 1 January 2008, milk with butterfat content outside the ranges defined by the European Commission could not legally be sold as milk. This included 1% milk, meaning The One, a 1% variety launched by Robert Wiseman Dairies, could not be labelled as milk. Lobbying by Britain has allowed these other percentages to be sold as milk. Since the change in regulation, Sainsbury's has launched a 1% variety with an orange milk bottle top.