Food Tech - Microorganisms, Enzymes & Food poisoning

Question 1

3 types of microorganisms

Answer 1

1. bacteria
2. moulds
3. yeasts

Question 2

mould

Answer 2

• microorganism
• tiny fungi which produce thread-like filaments
• spoil bread, cheese and fruit
• changes smell, looks and taste (fuzzy appearance)
• toxins still remain

Question 3

yeasts

Answer 3

• tiny single-celled fungi which reproduce by budding
• commonly grow on surfaces of fruits
• spoil fruit by fermenting the sugars, turning them into alcohol and C02

Question 4

bacteria

Answer 4

• single-celled micro-organisms

Question 5

3 types of bacteria

Answer 5

1. harmless bacteria : can be helpful
2. pathogenic bacteria : makes us ill
3. food spoilage bacteria : makes food decay / rot

Question 6

5 factors microorganisms need to grow

Answer 6

1. food
2. moisture
3. warmth
4. pH lvl
5. time

Question 7

temperatures

Answer 7

75 = cook from raw & to re-heat
63+ = bacteria starts to die
5 - 63 = bacteria multiplies (danger zone)
0 - 5 = chill food
-18 - -24 = bacteria is dormant (alive but inactive)

Question 8

how to slow growth (3)

Answer 8

1. fridge (0-5) = change temp
2. add salt = salt absorbs water (removes moisture)
3. pickle food in vinegar = changes pH

Question 9

high risk foods (5)

Answer 9

1. cooked meat, fish and poultry
2. dairy products
3. gravies, stock & sauces
4. shellfish
5. cooked rice

Question 10

enzymes

Answer 10

• special proteins
• speed up chemical reactions (biological catalysts)

Question 11

2 enzymic reactions

Answer 11

1. ripening
2. browning

Question 12

ripening - enzymic reaction

Answer 12

• enzymes in fruit causes them to ripen
• changes sweetness, colour & texture of furuit
  eg. unripe bananas are green and firm => enzymes break down starch inside to make banana softer and sweeter

Question 13

browning - enzymic reaction

Answer 13

• after slicing fruits, oxygen in air will turn the fruit brown
• enzymes in fruit will speed up this process (oxidation)
• leaving some fruit to overripen will give brown color as well

Question 14

how to slow enzymic reactions (2)

Answer 14

1. adding an acid (ACID)
2. blanching (HEAT)

Question 15

adding acid - slowing enzymic reaction

Answer 15

• enzymes have optimal pH lvl
• dip slices of fruit in lemon juice

Question 16

blanching - slowing enzymic reaction

Answer 16

• plunging into boiling water for short period
• heat causes enzymes to lose structure (denaturation)

Question 17

people at high risk of food poisoning (4)

Answer 17

1. elderly people : too old
2. babies : not developed
3. anyone who is ill : immune system altered
4. pregnant women : two people

Question 18

factors affecting food poisoning

Answer 18

1. preparation too far in advance
2. poor hygiene
3. undercooking

Question 19

symptom of food poisoning

Answer 19

• severe vomiting
• exhaustion
• headache
• fever
• abdominal pain

Question 20

preventing food spoilage - buying food

Answer 20

• dented, blown or rusted cans
• frozen food which has frozen together
• only shop in clean hygienic stores

Question 21

preventing food spoilage - transporting food

Answer 21

• buy chilled and frozen foods at the end
• keep separate (cooked & uncooked, dry and moist, households chemicals)

Question 22

preventing food spoilage - storing food

Answer 22

• unpack asap
• old stocks b4 new ones
• store food in correct places

Question 23

8 types of bacteria

Answer 23

1. clostridium botulinum
2. campylobacter
3. clostridium perfringen
4. E coli 0157
5. salmonella
6. staphylococcus aureus
7. listeria
8. bacillus cereus

Question 24

clostridium botulinum - sources

Answer 24

• fish and meat
• dust, soil & vegetable
• faulty canning

Question 25

campylobacter - sources

Answer 25

- raw and undercooked poultry - unpasteurized milk - contaminated water

Question 26

clostridium perfringens - sources

Answer 26

- animal and human waste - dust, soil and vegetables - raw meats - insect

Question 27

E coli 0157 - sources

Answer 27

- raw and undercooked meat and poultry - unwashed vegetables - contaminated water

Question 28

salmonella - sources

Answer 28

- raw meat, poultry & eggs - flies, people, sewage & contaminated water

Question 29

staphylococcus aureus - sources

Answer 29

- humans nose, mouth and skin - untreated milk

Question 30

listeria - sources

Answer 30

- unpasteurised milk & dairy product - cook-chill foods - pate - meat - poultry - salad vegetables

Question 31

bacillus cereus - sources

Answer 31

- rice and cereals - dust, soil and vegetables

Question 32

clostridium botulinum - sign and symptoms

Answer 32

- onset for 12-36 hours - voice change - double vision - drooping eyelids - severe constipation - death within a week / slow recovery over months

Question 33

campylobacter - sign and symptoms

Answer 33

- onset 2-5 day - fever, headache, dizziness, abdominal pain - lasts 2-7 days - can recur

Question 34

clostridium perfringens - sign and symptoms

Answer 34

- onset 12-18 hours - abdominal pain, diarrhoea and nausea - lasts 12-48 hours

Question 35

E Coli 0157 - sign and symptoms

Answer 35

- onset 3-4 days - diarrhoea that has blood - can lead to kidney failure or death

Question 36

salmonella - sign and symptoms

Answer 36

- onset 6-48 hours - headache, aching of limb, abdominal pain, diarrhoea, vomiting and fever - lasts 1-7 days - rarely fatal

Question 37

staphylococcus aureus - sign and symptoms

Answer 37

- 1-6 hours - severe vomiting, abdominal pain, weakness and lower than normal temp - 6-24 hours

Question 38

listeria - sign and symptoms

Answer 38

- 1-70 days - range from mild, flu-like illness - during pregnancy => miscarriage / birth of infected baby

Question 39

bacillus cereus - sign and symptoms

Answer 39

- ranges nausea, vomiting and abdominal cramps - incubation period of 1-6 hours - less than 24 hours after onset