MILK Understand the structure and nutrition of different types of milk Recognise the various processes that milk can undergo Rank in order of preference your favourite milk
What is milk? Milk is mostly water, approximately 87 per cent, and if you removed all the water you’d be left with what is called the solid component. This is made up of milk fat (cream), a natural milk sugar (lactose) and milk protein together with vitamins and minerals - and all of these elements can vary depending on the type of cow the milk came from, what the cow has been eating and the time of year.
Importance of Milk • Calcium is essential for growing and developed bones. As we cannot make calcium, a calcium-rich diet is a top priority for bones. • An amazing 90% of our adult skeleton is formed by the age of 18 (earlier in girls), and by the age of 20 almost our entire skeleton is formed.
Calcium 200ml Very rich source of Calcium
Fat in Milk • There is far less fat in milk than many people think. • Even whole milk (full-fat milk) contains only 3.9% fat. suitable for children • Semi-skimmed milk has less than half this amount (1.7% fat) • Skimmed milk is virtually fat-free (0.3% fat).
Processes Pasteurised 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.
Processes This involves forcing the milk at high temperatures through small holes. This breaks up the fat globules in order to spread them evenly throughout the milk and prevents the separation of a cream layer. Homogenised Fat
Processes UHT • 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. • UHT milk is available in whole, semi skimmed and skimmed varieties.
Semi skimmed milk • 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 • 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. • 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 the 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 • 1% fat milk is now offered to consumers who like the taste of semi-skimmed, but want to enjoy milk with a lower 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 • Organic milk comes from cows that have been grazed on pasture that has no chemical fertilisers, pesticides or agrochemicals used on it. 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. Lactose free milk • Some people are lactose intolerant. Lactose is a type of carbohydrate but some people cannot digest it.
Evaporated Milk • Evaporated milk is a concentrated, sterilised milk product. It has a concentration twice that of standard milk. • The process of producing evaporated milk involves standardising, heat treating and evaporating the milk under reduced pressure, at temperatures between 60ºC and 65ºC. • The evaporated milk is then homogenised to prevent it separating under storage and then it is cooled. • The evaporated milk is poured into cans, which are then sealed. At this point the cans are moved to a steriliser where they are held for 10 minutes. • A cooling stage follows and the cans are then labelled and packed. • As a result of processing, evaporated milk possesses a characteristic cooked flavour as well as a characteristic colour. • The shelf-life of canned evaporated milk is commonly stated as one year.
Condensed Milk • Condensed milk is concentrated in the same way as evaporated milk, but with the addition of sugar. • This product is not sterlised but is preserved by the high concentration of sugar. It can be made from whole milk, semi skimmed or skimmed milk. • The heat treatment used consists of holding standardised milk at a temperature of 110-115ºC for one to two minutes. • The milk is then homogenised, the sugar added and the sweetened milk is then evaporated at low temperatures (between 55-60ºC). The concentration of the condensed milk is now up to 3 times that of the original milk. • The milk is then cooled rapidly to 30ºC and packaged.
Cow to Consumer 1. MilkingCows are milked two or three times a day, using electric milking machines which have special suction cups that are attached to the cows’ teats. Milking this way does not hurt the cow at all. But before any cow is milked, the dairy farmer must ensure all staff are wearing clean clothing and have clean hands. Also all the equipment must be clean and sterile and the cows’ udders must have been washed to remove any dirt. 2. Farm StorageAfter the cows have been milked, the fresh milk is pumped to the farm’s storage vats where it is filtered, cooled and stored at or below 4˚C.
Cow to Consumer . Leaving the FarmLarge milk tankers are used to transport the milk from the dairy farm to the factory. One tanker may collect milk from a number of dairies. Before accepting the milk, the tanker drivers test it to make sure it is okay - it must be clean and smell fresh, and comply with all health standards. The milk tankers are insulated to keep the milk at or below 4˚C. 4. At the FactoryWhen milk is received at the factory it must again be checked to ensure it has been kept at or below 4˚C during distribution and delivered within 24 hours after it is milked. The milk is then pumped into large insulated vats at the factory. All machinery and equipment at the factory is cleaned regularly. Samples of the milk are taken at various stages during processing to check the temperature and quality. 5. PasteurisationThe next step is pasteurisation, which allows milk to stay fresh longer. Using the High Temperature Short Time method, the milk is heated to not less than 72˚C for no less than 15 seconds. This kills any potentially harmful bacteria and extends the shelf life of the milk. The milk is then rapidly cooled to 4˚C.
Cow to Consumer 6. HomogenisationAll milk is homogenised, to prevent the cream separating and settling on top. During the homogenisation process, the milk is forced through tiny holes at high pressure which breaks up the fat globules (cream) into tiny particles. This results in the cream spreading throughout the milk in a permanent suspension. 7. PackagingMilk is then sent through a processing line to be packaged in cartons or bottles. Cartons are made from cardboard lined with a polyethylene plastic. The cartons, in varying sizes, are flat and then are formed into their proper shape in a machine just before being filled. Once the correct amount of milk has been put in, the carton is heat sealed, stamped with the ‘use by date’ and packaged in milk crates. Milk bottles also come in various sizes. These are made on-site or are bought. Just like cartons, milk bottles are filled, then capped, stamped with the ‘use by date’ and packaged in milk crates. 8. DistributionEvery day, milk is distributed from the factory to various milk depots in refrigerated trucks. At the depots, the milk is picked up by milk vendors in smaller trucks and distributed to supermarkets, corner stores, schools, cafes and households.
Basic Recipe • 250g/9oz macaroni • 40g/1½oz butter • 40g/1½ plain flour • 600ml/1pint 1½fl oz milk • 300g/9oz grated cheddar The Garnish of your choice