Food Spoilage

Question 1

Causes of food spoilage

Answer 1

Enzyme action
Moisture loss
Microbial contamination

Question 2

What are enzymes

Answer 2

Protein catalyst that are naturally found in food that speed up chemical reactions without being destroyed

Question 3

3 things enzymes do in food

Answer 3

Ripen food
Brown food
Deteriorate food

Question 4

What does ripening do

Answer 4

Improve taste - get sweeter as start getting turns to sugar
Colour change
Texture change eg banana

Question 5

Why do enzymes cause cut food to become brown

Answer 5

The enzyme named oxidase from the cell wall reacts with the oxygen in the air (a process called oxidation) and causes browning

Question 6

Examples of enzymic denaturation

Answer 6

Fish - naturally present enzymes speed up spoilage

Veg - naturally present enzymes causes deterioration

Question 7

Ways of preventing enzymic spoilage

Answer 7

Acids - lowers ph eg lemon juice
Heat - inactivates enzymes eg stewing apples
Additives - sulfur dioxide eg in dried fruit
Cold temperatures - slows down eg fish
Blanching

Question 8

Why would veg and fruit lose moisture

Answer 8

Once harvested they no longer absorb moisture from soil via roots

Question 9

Dehydrated fruit and veg

Answer 9

Shrink/shrivel
Wrinkle
Limp

Question 10

Are yeast and mould visible

Answer 10

Yes

Question 11

Are mycotoxins carcinogenic

Answer 11

Yes

Question 12

What are mycotoxins

Answer 12

Toxins produced by mould

Question 13

Why don’t mould and yeast call food poisoninh

Answer 13

People see them and don’t eat them

Question 14

Why is bacteria food poisoning more common

Answer 14

Not visible on exterior of the food so people eat them

Question 15

Types of food poisoning

Answer 15

Chemical
Biological
Bacterial

Question 16

Examples of chemical food poisoning

Answer 16

Lead

Pesticides / herbicides

Question 17

Examples of biological food poisoning

Answer 17

Solanine in green potatoes

Haemagglutin in raw red kidney beans

Question 18

Two types of bacterial food poisoning

Answer 18

Infectious

Toxic

Question 19

Infectious food poisoning

Answer 19

Pathogenic bacteria that produces endotoxins (made inside pathogenic cell)
Released when cell dies
Destroyed by normal cooking temp
Incubation period ; over 12 hours

Question 20

Examples of infectious poisoning

Answer 20

Salmonella
Listeria
E. coli

Question 21

Toxic food poisoning

Answer 21

Food containing pathogenic bacteria that produces exotoxins (secreted by cell wall as they grow)
Produced before or after food is eaten
Difficult to destroy - boil 30 min
Incubation period - 2 hours

Question 22

Examples of toxic poisoninh

Answer 22

Staphylococcus

Clostridium botulinum

Question 23

What is the incubation period

Answer 23

The time it takes for symptoms to appear

Question 24

Describe salmonella

Answer 24

Infectious 
Contagious
Facultative
Neutral ph
Op temp = 37

Question 25

Sources of salmonella and high risk foods

Answer 25

Human and animal faeces
Unwashed hands
Rodents and pests
Raw/undercooked eggs, fish, meat, poultry 
Unpasteurised milk and cheese

Question 26

Symptoms of salmonella

Answer 26

Nausea
Vomiting
Abdominal pain
Diarrhoea
Fever

Question 27

Incubation period and duration of food poisoning for salmonella

Answer 27

12-36h

Lasts 1-7 days (up to a week)

Question 28

Describe clostridium botulinum

Answer 28

Toxic
Not contagious
Anaerobic
Slightly acidic
Optimum temp = 30-37

Question 29

Sources of clostridium botulinum and high risk foods

Answer 29

Soils
Vegetables
Pig intestines
Unpasteurised cheese
Canned food
Vacuum packed food

Question 30

Symptoms of clostridium botulinum

Answer 30

Diarrhoea
Slurred speech
Dizziness
Double vision

Question 31

Incubation period and duration of poisoning for clostridium botulinum

Answer 31

12-36h

Lasts 1-8days