Whole milk Natural whole milk is milk with nothing added or removed. Whole standardised milk is whole milk standardised to a minimum fat content of 3.5%. Whole homogenised milk is identical in fat and nutrient content to whole standardised milk however it has undergone a specific process known as “homogenisation” which breaks up the fat globules in the milk. This spreads the fat evenly throughout the milk and prevents a creamy layer forming at the top. How is it produced? Natural whole milk is collected from the dairy herd and undergoes various processing techniques before it reaches the shelf for consumption by the general public. Most of the milk consumed in Europe, Scandanavia, the USA, Australia and New Zealand is pasteurised. Pasteurisation is the process whereby milk is heated with the purpose of killing potentially harmful micro-organisms such as certain pathogenic bacteria, yeasts and moulds which may be present in the milk after initial collection. This helps to protect against any food born illness that can occur through consumption of raw (unpasteurised) milk. Following pasteurisation, the milk is rapidly cooled and is then stored in a refrigerator in order to preserve its shelf life. Various pasturisation and heat treatment techniques can be used in the production of milk which can affect storage capacity-detailed in later sections. Much of the milk in the market is now homogenised as well as pasteurised. Homogenisation offers a way to reduce the fatty sensation of whole milk and prevent the formation of a cream plug.
UHT milk UHT or ultra heat treated milk is a form of milk that has been heated to a temperature of at least 135ºC in order to kill off any harmful micro-organisms (e.g. harmful bacteria) which may be present in the milk. The milk is then packaged into sterile containers. All milk that is available for sale to consumers through supermarkets and milkmen must be pasteurised i.e. heated to 71.7ºC in order to make it safe for consumers and improve its shelf life. However UHT milks have a longer shelf life as a result of the higher temperatures to which they are heated and the packaging used to store them. UHT milk is available in whole, semi skimmed and skimmed varieties.
There are many different varieties of milk available for consumption within the UK. The different milks tend to vary according to the way they are produced, and their fat content. The fat content of milk varies depending on the product e.g. whole milk has a fat content of about 4% fat, whole standardised milk, that which is widely available for sale, has a minimum fat content of 3.5% fat, semi skimmed milk contains 1.7% fat, skimmed milk contains about 0.1% fat, and in addition there is 1% fat milk.