cheese hygiene

Question 1

protein types of cheese

Answer 1

casein cheese (from milk)
albumin cheese (whey)
casein-albumin cheese

Question 2

milk storage for cheese

Answer 2

if long storage needed, theorisation 63-69oC 10-60s, storage 2-3oC

Question 3

thermal processing of milk

Answer 3

• high temps not favourable
• minimal processing at 65oC destroys most of bacteria
• thermalisation: enzymes not destroyed
• milk pasteurisation 63-65oC for 30m, 72-73oC for 15-20s
• use of bactofuge separator and microfiltration

Question 4

milk bactofuge separation

Answer 4

• centrifugal separation of bactiera
• 2 fraction
• 8-90% of total bacteria count in milk
• concentrate acan be sterilised, cooled and processed

Question 5

milk microfiltratio

Answer 5

• separation of bacteria by membrane
• +ves
• without adding nitrites, control of cheese ripening and extended shelf life

-ve
- fat and protein particles same size as bacteria

Question 6

additives

Answer 6

• low quality milk = produce soft curd
• CaCl - achieving constant curdling and firm curd
• nitrates = prevention of growth of coliform and clostridia
• lysozyme = control of clostridia
• colours = extracts B-caroten

Question 7

curdling /coagulation

Answer 7

• after thermal processing and mixing milk with ingredients
• rennet - 20-30ml with 100kg milk
• mix 2-3 m and curdling under 30oC
• higher temp faster formation of firm curd

Question 8

curd processing

Answer 8

formatted curd is cut to different size particles

mild heating for firm structure of curd (35-40C ) (hard cheese 40-45oC)

Question 9

cheese salting

Answer 9

• NaCl
• semihard and hard cheese
• brine tanks
• after brining - cheese dries

Question 10

maturation/ ripening

Answer 10

• soft cheese ripen at lower temp and shorter itime and hard cheese is opposite

Question 11

semi hard and hard cheese

Answer 11

• 1st 2 weeks turned and wiped more often (every 2-3 days)
• too dry climate = fast drying = poor quality cheese
• humid climate = growth of mould = spoilage of cheese
• prevent drying = cheese wiped with moist cloth and wet cheese = dry cloth
• be protected with paraffin
• ripening takes at least 2 months

Question 12

smear-ripened cheese, washed-rind

Answer 12

• maturation should be ensured
• brevibacterium lines = red-smear
• forming regular tin skin on surface
• cheese too dry-smear won’t develop, if too wet slime will form

Question 13

brined cheese

Answer 13

• ripening takes place in brine at 12-16oc lasts 2-3 hrd
• can be stored up to 1 year

Question 14

soft-ripened cheese

Answer 14

white mould
- when formed is wrapped with aluminium and stored at lower temp

blue mould
= injected several times with needles after 2-3 w (gorgonzola) or 5-6 weeks (stilton)

Question 15

biochemical process during cheese maturation