L25: OPOAO Flashcards Preview

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Flashcards in L25: OPOAO Deck (79)
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1
Q

Who performs dairy hygiene inspections?

A

FSA inspectors

2
Q

What is wet curing?

A

Brine injections

3
Q

What % of salt is used?

A

1-5%

4
Q

Above what % salt is shelf-stable?

A

Over 5%

5
Q

What microbes do nitrites inhibit?

A

Spore forming

6
Q

What is a disadvantage of nitrites?

A

Form toxic nitrosamines while frying

7
Q

What other food factors do nitrites affect?

A

Stabilises pigment, influences flavour

8
Q

How do phosphates work?

A

Water retention agents

9
Q

What is the usual form of phosphates used?

A

Alkaline polyphosphates

10
Q

How does lipid oxidation affect microbial growth?

A

Less lipid oxidation = less microbial growth

11
Q

How do erythorbic or ascorbic acids affect nitrosamines?

A

Promote nitric oxide so less nitrosamines

12
Q

How can corn syrup act as a preservative?

A

Water binding properties

13
Q

What is difference between a seasoning and a flavouring?

A

Seasonings modify flavour, flavourings strengthen specific flavours

14
Q

What are two examples of meat tenderisers?

A

Salt and some proteolytic enzymes

15
Q

What is nicin used for and how does it work?

A

Bacteriocin used in casings or packaging material

16
Q

What do antioxidants prevent?

A

Lipid oxidation

17
Q

What are some examples of antioxidants?

A

Citric acid, polyphosphates, EDTA, natural ingredient from rosemary

18
Q

What is important when using an acidifier?

A

Timing

19
Q

What is added to “raw meat fermented sausages”?

A

Salt, lactic acid bacteria, sugars, nitrite, spices

20
Q

What temperature are raw meat fermented sausages fermented at?

A

15-30 degrees

21
Q

What prevents Salmonella and staph aureus in raw meat fermented sausages?

A

Salt, fast initial acid, drying, maturing

22
Q

What prevents Clostridium in raw meat fermented sausages?

A

Nitrites

23
Q

What prevents E Coli in raw meat fermented sausages?

A

High initial temperature and long drying

24
Q

In which countries is raw cows milk allowed?

A

UK but not Scotland

25
Q

What objects are responsible for most of the contamination of raw milk?

A

Milk handling eqipment

26
Q

What objects are responsible for most of the zoonoses of raw milk?

A

Udder (and rodents and foreign bodies)

27
Q

What is the max milk temperature is daily collection?

A

8 degrees

28
Q

What is the max milk temperature if collection is every other day?

A

6 degrees

29
Q

What 7 factors is milk tested for?

A

Protein, butterfat, lactose, SCC, microbial quality, antibiotic residues, water

30
Q

Which 4 factory determine milk quality?

A

Protein, butterfat, lactose, SCC

31
Q

How are antibiotic residues tested for in milk?

A

ELISA

32
Q

How is water content tested for in milk?

A

Freezing point

33
Q

In raw cows milk, what is the maximum plate count at 30 degrees?

A

<100,000 per ml

34
Q

In raw cows milk, what is the maximum somatic cell count at 30 degrees?

A

<400,000 per ml

35
Q

If unpasteurised, what must the plate count be below?

A

<20,000

36
Q

If unpasteurised, what must the coliform count be below?

A

<100

37
Q

In raw other species milk, what is the maximum plate count at 30 degrees?

A

<1,500,000 per ml

38
Q

If processed without heat (some cheeses), what must the plate count be below?

A

<500,000 per ml

39
Q

What do milk buyers use as a measure of quantity?

A

Bactoscans

40
Q

What amount of water and temperature do you need when cleaning a milking unit?

A

10-15L per milking unit at 85 degrees at the start and no less than 50 degrees at the end

41
Q

What amount of water and temperature do you need when cleaning a milking unit with acidified boiling water?

A

14-18L per unit starting at 96 degrees and all parts of equipment must reach 77 degrees for at least 2 minutes

42
Q

What temperature and time is pasteurisation?

A

72 degrees for 15 seconds

43
Q

Which two tests must milk have following pasteurisation?

A

Microbiological assessment and phosphatase test

44
Q

What temperature must milk be for chilled storage?

A

Less than 6 degrees

45
Q

How can you modify curd when making cheese?

A

Heat, pressure, ripening ferments, special moulds, seasoning

46
Q

What are the three types of cheese?

A

Hard, semi-hard, soft

47
Q

Which kind of cheese can be with or without gas holes?

A

Very hard

48
Q

What are two ways of ripening semihard cheese?

A

Moulds (Roquefort) or bacteria (Brick)

49
Q

What are two ways of ripening soft cheese?

A

Bacteria (limburger), mould (camembert) or unripened (cottage)

50
Q

How soon must milk be treated or processed if refrigerated below 6 degrees?

A

36 hours

51
Q

How soon must milk be treated or processed if refrigerated below 4 degrees?

A

48 hours

52
Q

How soon must buffalo, ewe or goats milk be treated or processed?

A

72 hours

53
Q

What does thermisation do?

A

Improves the keeping quality before processing, but does not destroy pathogens

54
Q

What temperature and time for thermisation?

A

57-68 for 15 seconds

55
Q

What must starting cfu/ml be for thermisation to work?

A

100,000 cfu/ml

56
Q

What do you not need to do when making soft cheese?

A

Heat

57
Q

What happens during curd preparation to make soft cheese?

A

Add blue moulds e.g. penicillium

58
Q

How are curds ripened?

A

Salted or brined

59
Q

What temperature, humidity and time are curds ripened for?

A

10 degrees and 95 humidity for 60 days

60
Q

Which test ensures effective pasteurisation?

A

Phosphatase test

61
Q

Why must you rotate stock and check acid development in cheese?

A

Slow acid development may result in bacterial proliferation

62
Q

What is one problem that can happen during ripening?

A

Overgrowth of contaminants

63
Q

What are three common cheese contaminants?

A

Salmonella, Listeria, Staph enterotoxins

64
Q

What does rennin do?

A

Coagulates the casein of milk and forms an insoluble calicum complex

65
Q

How can you harvest rennin?

A

Blumenthal process, HCl process, Keil process

66
Q

Why are enzyme combinations used with rennet?

A

Low proteolytic activity

67
Q

How much of milk is made into cream and butter?

A

1/3

68
Q

What % salt is added to cheese?

A

10-13%

69
Q

What are three ways salt improves keeping quality of cheese?

A

Reduces microbial growth, inhibits yeast and mould, inhibits proteolytic and lipolytic organisms

70
Q

How do you disinfect fruit before opening?

A

Dip in 336ppm chlorine for 2 mins before opening

71
Q

What diameter filter do you use for butter?

A

0.1mm

72
Q

Above what concentration lactic acid do caseins coagulate?

A

Over 1g/100ml

73
Q

How does cooling affect fermentation?

A

Halts

74
Q

From which pH is the base stirred?

A

4.6

75
Q

What is the ideal pH of a fermentation starter culture?

A

4.2-4.3

76
Q

How long does fermentation take to form a bio-product?

A

4-5 hours

77
Q

How long does fermentation take to form a mesophilic product?

A

12-16 hours

78
Q

What does the flavour of butter come from?

A

Milk components esp fat and products of certain bacteria eg Strep lactis

79
Q

How can emulsion of water in fat allow bacterial growth?

A

Low moisture should prevent, but if emulsified there is still sufficient water and soluble food so growth can occur between the fat globules

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