Dairy 2 - milk processing

Question 1

Why should we process milk? 2 reasons

Answer 1

To kill pathogenic microbes and to increase shelf life

Question 2

What do spoilage bacteria do?

Answer 2

Degrade milk through enzymatic processes

Question 3

What are the 4 types of spoilage bacteria?

Answer 3

Lipases
Proteinases
Lactose
Phospholipase

Question 4

Lipases function

Answer 4

hydrolyse milk fat leading to rancidity

Question 5

Proteinases function

Answer 5

break down proteins with water giving age gelation and bitter flavours

Question 6

Lactose function

Answer 6

fermented to lactic acid leading to sourness

Question 7

Phospholipase function

Answer 7

breaks down milk fat globule membrane leading to creaming

Question 8

State the 4 methods for milk processing

Answer 8

pasteurisation
homogenisation
evaporation
coagulation

Question 9

Define pasteurisation

Answer 9

Heating food to specific temp for food safety

Question 10

What does paesturisation destroy?

Answer 10

pathogenic bacteria

Question 11

Define homogenisation

Answer 11

reduces fat globule size and prevents separation of water and fat

Question 12

What attributes does homogenisation give to milk?

Answer 12

Whiter colour and creaminess

Question 13

Define milk evaporation

Answer 13

Undertaken in a vacuum to reduce the boiling point to provide microbial stability

Question 14

Define coagulation

Answer 14

Can be done with acid, enzyme (chymosin) or salt

Question 15

Effect of coagulation

Answer 15

turns milk into cheese