Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

VPH Lectures > Food Technology > Flashcards

Food Technology Flashcards

1
Q

Define food technology

A

Food technology is the study of how different foods can be used and made into food products from production to consumption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the main aims of food preservation

A

Minimising microbial growth therefore promoting longer shelf life and reduced hazards from eating food

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Name the 6 intrinsic factors which affect microbial behaviours in food

A
  1. Nutrient content of food
  2. Natural antimicrobial substances in food
  3. pH change and the food’s ability to resist pH change
  4. The oxidation-reduction potential, and its ability to resist redox change
  5. The water activity of the food
  6. Mechanical barriers to microbial invasion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the nutritional requirements of microorganisms to grow in food (x4)

A

Water
Energy source e.g. sugars, amino acids, alcohols
Source of nitrogen - primary source is amino acids
Vitamins and minerals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Name some antimicrobial substances which naturally reside in food

A

Essential oils in some plants e.g. garlic and cloves
Milk - lactoferrin, rotavirus inhibitor, conglutinin, lactoperoxidase system
Lysozyme in eggs and milk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Discuss how pH affects microbial growth in food

A

Most microorganisms grow best around pH 7, few grow below pH 4
Buffered foods resist pH change best e.g. meat is more highly buffered than veg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Discuss how the oxidation-reduction potential of food relates to microbial growth

A

Aerobic microorganisms require an oxidised environment to grow
Anaerobes require a reduced environment t grow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What determines the oxidation-reduction potential of food

A
  1. The resistance to change in potential of the food (poising capacity)
  2. The oxygen tension of the atmosphere around the food.
  3. The access that the atmosphere has to the food.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does water activity relate to microbial growth

A

Reducing the amount of water available for microbial growth is an extremely important and very ancient way of preserving foods:

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Give an example of a mechanical barrier agains micro-organisms

A

Skin - meat or veg
Fermented meat products

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Name the 4 extrinsic factors that affect microbial growth in food

A
  1. Temperature
  2. Gaseous atmosphere surrounding food
  3. Relative humidity surrounding the food
  4. Time
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the optimum temperature of growth for psychrotrophs

A

Optimum = 20-30 degrees
Will grow at 7 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the optimum temperature of growth for psychrophiles

A

Optimum = 15 degrees or lower

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the optimum temperature of growth for mesophiles

A

Optimum = 30-40 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the optimum temperature of growth for thermophiles

A

Optimum = 55-65 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the D value when referring to the thermal destruction of bacteria

A

The time taken for the population to pass through a log cycle (90% of the population is killed) at a certain temperature.
E.g. D121 = the time required to kill 90% of a population of microorganisms at 121 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What does the thermal processing of 1D, 2D, 3D and 4D mean

A

1D = causes a 90% reduction of the original population
2D = causes a 99% reduction of the original population
3D = 99.9% reduction
4D = 99.99% reduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Why are some bacteria so much more heat resistant

A

They are spore forming

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the Z value when referring to the thermal destruction of bacteria

A

The Z value is the temperature change that is required to change the D value by a factor of 10.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Which atmospheric gas is the most important in controlling microorganisms in food, and wha other gas can be used

A

Most important - Carbon dioxide
Other - Ozone

21
Q

When should ozone NOT be used to help preserve food

A

Should not be used on high-lipid-content foods since it would cause an increase in rancidity.

22
Q

Why is relative humidity important for storing food

A

Foods that undergo surface spoilage from moulds, yeasts, and certain bacteria should be stored under conditions of low Relative Humidity

23
Q

Name the 8 reasons food can be rejected as spoiled

A
  1. Organoleptic changes.
  2. Chemical changes.
  3. Physical damage.
  4. Freezer burn.
  5. Staling.
  6. Ripening.
  7. Presence of foreign bodies.
  8. Contamination with chemical agents
24
Q

How are organoleptic changes caused and what 4 changes occur

A

Brought about by the growth of microorganisms
Changes in taste, odour, appearance and texture

25
Q

Give 2 examples of chemical changes that can spoil foods

A

Chemical oxidation of fats produces rancidity
Browning of fruit and veg in contact with air

26
Q

Name the 2 processes by which meat changes colour (spoiled)

A
  1. Oxygenation of myoglobin (Mb) and formation of oxymyoglobin (MbO2)
  2. Oxidation of myoglobin and formation of MetMb (metmyoglobin)
27
Q

Give 2 examples of physical damage that can spoil food

A

Improper handling
Biological risks - insects entering the food

28
Q

What causes freezer burn of food

A

Frozen food loses moisture which migrates to the coldest place => side of the freezer
The loss of the water molecules causes food the become dehydrated = freezer burn

29
Q

Name the cause of food becoming stale

A

Loss of water

30
Q

Why is food rejected as spoiled due to foreign bodies (x2)

A

Hard or sharp foreign bodies can cause the consumer injury
Foreign bodies can introduce harmful bacteria

31
Q

Name the 4 main categories or animal origin products

A

Meat and meat products.
Milk and Dairy products.
Fish and fish products.
Poultry and poultry products

32
Q

Name a method of meat preservation

A

Meat fermentation

33
Q

Why is nitrite essential in a. starter culture for fermentation

A

To prevent decolourization of the meat.
To prevent oxidative rancidity.

34
Q

Describe the process of ripening of fermented meats

A

Protein is hydrolysed by microbial proteinases to give amino acids and other breakdown products

35
Q

Why does fermentation give stability and safety

A

Combination of
- Low pH - due to presence of lactic acid
- Reduced water activity - bay addition of salt and drying

36
Q

Name the 5 common defects of fermented meats

A
  1. Growth of green or black moulds on the surface.
  2. Surface bacterial slime.
  3. Souring due to excess lactic acid production.
  4. Gassiness due to heterofermentative lactic acid bacteria.
  5. Greening of the meat pigment caused by the production of hydrogen peroxide by Lactobacillus viridans.
37
Q

Name 4 reasons canned food can spoil

A

Underfilling.
Quality of the can seam.
Improper handling.
Hygiene of the can transport system

38
Q

Apart from fermentation, name 2 other methods of food preservation

A

Canning
Smoking

39
Q

Name 2 causes of yogurt not setting

A

Antibiotic residues present
The culture is destroyed by bacteriophages

40
Q

Name the 3 types of yogurt

A

Set
Stirred
Yogurt drinks

41
Q

Name 3 microbial problems in cheese

A

Blowing effect - bacterial gas formation producing cracks
Mould growth
Bacteriophages attacking the started

42
Q

Name 7 reasons why microbiology can be applied in the food industry

A
  1. HACCP-based systems.
  2. Risk assessment.
  3. Raw materials/ingredients.
  4. Hygiene monitoring.
  5. Process monitoring.
  6. Finished products.
  7. Crisis management.
43
Q

Name 4 routes of hygiene monitoring in the food industry

A

Swabs - surfaces
Solid or liquid samples
Personnel - hand swabbing
Air - air sampling

44
Q

What does microbial criteria set limits for in food (x4)

A

Pathogen
Microbial toxins
Indicator microorganisms
Spoilage microorganisms

45
Q

What is a two-class sampling plan

A

Consists of n, c and m
n = the number of sample units from a lot that must be examined to satisfy a sampling plan
c = the maximum acceptable number of sample units that can exceed the microbiological criterion m
m = the maximum number or level of relevant bacteria per gram, values above this level are either marginally acceptable or unacceptable

46
Q

What is a three-class sampling plan

A

Consists of n, c, m and M
n = the number of sample units from a lot that must be examined to satisfy a sampling plan
c = the maximum acceptable number of sample units that can exceed the microbiological criterion m
m = the maximum number or level of relevant bacteria per gram, values above this level are either marginally acceptable or unacceptable
M = the quantity which is used to separate marginally acceptable from unacceptable quality foods

47
Q

When would you use a two-class vs a three-class sampling plan

A

Two-class = used for presence or absence tests
Three-class = used for count or concentration tests

48
Q

What parameters are used to evaluate shelf life of a product

A

Deterioration in specific organoleptic qualities
Microbial growth

49
Q

What is challenge testing used to determine

A

Growth, death or survival of an organism under controlled temperatures and conditions

VPH Lectures (23 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions