There are many different varieties of milk available for consumption within the UK.
The different kinds of milk tend to vary according to the way they are produced and in their fat content.
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%.
Some EU member states may produce an additional category of whole milk with a minimum fat content of 4%.
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 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 borne 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.
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.
Semi-skimmed milk is the most popular type of milk in the UK with a fat content of 1.7%, compared to 4% in whole milk and 0.3% in skimmed milk.
Skimmed milk has a fat content of between 0.1-0.3 %. Skimmed milk, therefore, has nearly all the fat removed.
It contains slightly more calcium than whole milk and lower levels of fat-soluble vitamins, particularly vitamin A, as this is lost when the fat is removed - see nutritional composition of milks
The lower level of fat in skimmed milk reduces its calorie (energy) content. For this reason, it is not recommended for children under the age of 5 years as they need extra energy for growth. However, it is ideal for adults who wish to limit their fat or calorie intake.
Skimmed milk has a slightly more watery appearance than other types of milk and has a less creamy taste due to the removal of fat.
1% fat milk
The EU regulations for milk classification previously divided milk into three categories defined by the fat content; whole, semi-skimmed or skimmed. Prior to 2008, any milk that contained a different fat content was defined as a ‘milk drink’.
On the 1st of January, 2008 new regulations came into force to facilitate consumer choice. Now any milk with a fat content other than those laid out can also be considered as ‘milk’, provided that its fat content is clearly indicated on the packaging in the form of ‘….% fat’. However, these milks cannot be described as whole, semi-skimmed or skimmed.
Following this change in regulation 1% fat milk is now offered to consumers who like the taste of semi-skimmed, but want to enjoy milk with lower fat content.
The nutritional differences between semi-skimmed and 1% fat milk are small and dependent mainly on the difference in fat content. 1% fat milk contains 40% less total and saturated fat than standard semi-skimmed milk. In addition, it has a lower energy content than semi-skimmed, and slightly lower levels of vitamins A and E, but has a higher calcium content.
Organic milk comes from cows that have been grazed on pasture that has no chemical fertilisers, pesticides or agrochemicals used on it.
The producers must register with an approved organic body and are subject to regular inspection.
Once the cows have been milked, the milk is treated in exactly the same way as regular pasteurised milk.
There is no evidence to suggest that organic milk is any more nutritious than conventionally produced milk. Although there have been studies to show that organically produced milk contains higher levels of omega-3 polyunsaturated fatty acids, these are plant-derived, short-chain fatty acids which appear to be of limited health benefit compared to the longer-chain omega-3 fatty acids found in oily fish.
Jersey and Guernsey milk
Channel Island milk is produced from Jersey or Guernsey breeds of cow and has a particularly rich and creamy taste.
It tends to be slightly higher in calories and fat than regular whole milk and also has a higher content of fat-soluble vitamins -particularly vitamin A which is important for the promotion and maintenance of healthy growth and development -see nutritional composition of milks
Jersey and Guernsey milks tend to have a visible cream line and are commonly found in supermarkets as “breakfast milk”.
The flavoured milk market is one of the fastest-growing dairy sectors.
There are a wide variety of flavours and consistencies to cater for all ages and tastes with a choice of long-life (i.e. Ultra Heat Treated or sterilised) or fresh flavoured milk.
Most flavoured milk products are produced using reduced-fat milk varieties and usually have a fat content of around 1%.
Heat treated milks
Approximately 99% of milk sold in the UK is heat-treated, to kill harmful bacteria and to improve its shelf life.
Pasteurisation is the most popular method of heat treatment. It is a relatively mild form of treatment, which kills harmful bacteria without significantly affecting the nutritional value or taste of the milk.
The basic process for whole milk involves heating the milk to a temperature of no less than 71.7ºC for a minimum of 15 seconds (max 25 seconds). This process is known as High-Temperature Short Time (HTST).
Sterilised milk is available in whole, semi-skimmed and skimmed varieties. It goes through a more severe form of heat treatment, which destroys nearly all the bacteria in it.
First, the milk is pre-heated, sterilised, then homogenised (see below) and poured into glass bottles or plastic cartons, which are closed with an airtight seal.
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.
Evaporated milk is a concentrated, sterilised milk product. It has a concentration twice that of standard milk.
Condensed milk is concentrated in the same way as evaporated milk, but with the addition of sugar.
This product is not sterilised but is preserved by the high concentration of sugar.
Sweetened condensed milk is commonly used in the sugar confectionery industry for the production of toffee, caramel and fudge.
Untreated (raw) milk
All milk sold via the supermarkets and milkmen has to be heat-treated (pasteurised) to kill harmful bacteria. However, untreated milk can be bought direct form a limited number of farm distributors in England and Wales.
The farmer must hold a licence from DEFRA, the Department for Environment, Food and Rural Affairs to be able to sell this milk.
In 1999 the government introduced tighter controls on the production of milk when sold untreated, including more prominent and comprehensive labelling. Labels must indicate that the milk has not been heated above 40ºC. I t must also carry the following warning: “This milk has not been heat-treated and ma, therefore,e contain organisms harmful to health”.
The government prohibited sales of untreated milk through shops, hotels and other catering establishments in 1989. The sale of untreated milk in Scotland was banned in 1983.
Untreated milk represents less than 1% of the household milk market.
Filtered milk goes through an extra, fine filtration system, which prevents souring bacteria from passing through.
The nutritional content of the milk is unaffected but the shelf life is increased.
Microfiltration adds an extra level of cleanness which can extend shelf life up to 45 days when stored at temperatures of up to 7ºC and an average 7 days once opened.
Filtered milk is available in whole, semi skimmed or skimmed milk varieties.
Dried milk powder
Milk powder is produced by evaporating the water from the milk using heat. The milk is homogenised, heat-treated and pre-concentrated before drying.
Homogenisation of milk involves forcing the milk at high pressure through small holes. This breaks up the fat globules in order to spread them evenly throughout the milk and prevent separation of a cream layer.
This process basically results in milk of uniform composition or consistency and palatability without removing or adding any constituents. Homogenisation increases the whiteness of milk because the greater numbers of fat globules scatter the light more effectively.
Most milk available on the market is homogenised at present.