Milk

Question 1

What is pasteurisation? What is used? how do they cool the milk so rapidly?

Answer 1

To destroy pathogenic bacteria without affecting the quality of the milk. a heat exchanger is used. Insulated stainless steel is used to rapidly cool it

Question 2

Name the 2 method used for pasteurisation and what they do for each

Answer 2

1. FLASH PROCESS - Milk is heated to over 72 degrees for 15seconds, then cooled rapidly.
2. HOLDER METHOD - milk is heated to over 63 degrees for 30mins then cooled rapidly

Question 3

Name the 3 ways milk is made

Answer 3

1. pasteurisation
2. homogenised
3. Sterilisation

Question 4

Describe the method homogenisation

Answer 4

The milk is push through tiny mesh to prevent fat separating and to give a uniform consistency

Question 5

What is sterilisation and name the 2 methods + what they do

Answer 5

Sterilisation kills more bacteria and extends shelf life:
1. Batch process: where milk is heated in bottles in autoclave at 113degrees for 15-40mins
2. Continuous process: bottles are passed on a conveyor belt through hot water tanks, into a steam chamber at 113 degrees for 15-40mins then into cooling tank

Question 6

Name the 5 different nutrients of milk

Answer 6

1. HBV protein
2. Fat
3. Carbs - lactose (disaccharide)
4. Calcium
5. Vitamin D+A

Question 7

Name the different types of milk

Answer 7

1. Frozen - not suitable, separates when thaws out + stored in polythene bags
2. Semi-skimmed - fat content is less than whole fat + sold pasteurised and UHT
3. Skimmed - Lower fat content, stored in cartons + bottles
4. Ultra-heated treated milk - 132degrees + kept in sealed package
5. Dried - substitutes where skimmed + non-milk are combined
6. Evaporated - at 115degrees for 20mins and it kept in sealed cans + is sterilised