MILK

What is milk?

Milk - mainly water, approx 87%.

The 13% is made up of milk fat (cream), a natural

milk sugar (lactose) and milk protein together with

vitamins and minerals.

Importance of Milk

• Milk is one of the best natural sources of calcium.

• Calcium is essential for growing and developed bones.

• Three portions of milk and dairy foods a day (3-A-Day).

Cow to Consumer1. Milking

Milked two or three times a day, using electric milking machines which have special suction cups that are attached to the cows’ teats.

2. Farm Storage After 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.

3. Leaving the FarmLarge milk tankers are used to transport the milk from the dairy farm to the factory.

4. At the FactoryThe milk is then pumped into large insulated vats at the factory. Samples of the milk are taken at various stages during processing to check the temperature and quality.

Jimmy’s Breakfast 5.15-12.40

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.

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. 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. 

8. DistributionEvery day, milk is distributed from the factory to various milk depots in refrigerated trucks.

Jimmy’s from the fridge 55-5.55 12.30-15.05

Fat in Milk

• Whole milk (full-fat milk) contains only 3.9% fat.

• Semi-skimmed milk has less than half this amount (1.7% fat)

• Skimmed milk is virtually fat-free (0.3% fat).

• 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.

Lactose intolerance• Milk contains lactose.• Our body produces an enzyme

lactase to digest lactose.• Some people don’t produce enough

lactase and therefore cant digest milk and dairy products (lactose intolerant)

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.

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.

• UHT milk is available in whole, semi skimmed and skimmed varieties.

Evaporated Milk

• Heat treating – evaporating at 60ºC and 65ºC – homogenised – cooled – poured into cans and sealed – labelled.

• 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 produced in

the same way as evaporated milk, but with the addition of sugar.

• Sweetened condensed milk is commonly used in the sugar confectionary industry for the production of toffee, caramel and fudge.

Dried Milk

• Water evaporated from the milk – homogenised – heat treated – dried.

• There are a number of ways to produce dried milk powder including spray drying and roller drying.

• If stored correctly, skimmed milk powders can be kept for up to one year. Once they are reconstituted, they must be treated as fresh milk.

Cheese

• Usually the milk of cows, buffalo, goats, or sheep, by coagulation.

• The milk is acidified, typically with a bacterial culture, then the addition of the enzyme rennet or acid or vinegar causes coagulation, to give "curds and whey".

What are curds and whey?

Curds- the solid lumpsyou find in milk whenmilk sours. You cantreat milk with enzymesto get the same effectWhey- The wateryliquid that you find inmilk when the milk

sours/ is treated withenzymes

Jimmy’s from the fridge 15.10-20.35

Cheese nutrition• Cheese supplies a great deal of

calcium, protein, and phosphorus.• Hard cheese = 33% fat• Soft cheese = 4% fat• Fat will depend on the type of milk

used during making.

Types of cheeseFresh:

Ripened:

Blue veined:

Semi soft:

Hard:

Processed:

Exam Style Questions1. Milk is an excellent source of what?

(1mark)

2. Explain the process of pasteurisation. (2marks)

3. Why is milk homogenised? (1mark)4. What is meant by lactose intolerance?

(1mark)5. What are curds and whey? (2marks)