Section 3: Food spoilage

Question 1

microorganisms and what are examples of them?

Answer 1

tiny living things found in everything that can be pathogenic, causing food spoilage
e.g bacteria, moulds, yeast

Question 2

What are the 5 conditions needed for microorganisms to grow and multiply quickly/

Answer 2

1. warm temperature
2. moisture
3. food
4. right PH
5. enough time

Question 3

How can you stop the growth of microorganisms?

Answer 3

• use a fridge to change the temp
• pickle fod in vinegar to reduce PH
• add salt to dry food out

Question 4

What are high risk foods and what are examples of them?

Answer 4

foods that are moist and high in protein for example: cooked meat, fish and poultry, dairy, cooked rice

Question 5

When can a food be described as high risk?

Answer 5

when it has been cooked and is ‘ready to eat’.

Question 6

How can you check that there are no visible signs of food spoilage?

Answer 6

fresh meat- should be rightly colour, firm and have a fresh smell

fresh fish- should have shiny skin, red gills, clear eyes and smell clean or slightly salty

Question 7

What can enzymes cause in foods?

Answer 7

ripening
browning- oxygen in air turns fruit and veg brown and enzymes in food speed this up

Question 8

How can you slow enzymes or stop them from working?

Answer 8

add acid as enzymes work at specific PH- you can dip fruits and veg in lemon juice

blanching- slows down enzymes and destroys ripening enzymes

Question 9

How can moulds and yeasts spoil food?

Answer 9

they are microorganisms (fungi).

mould- spreads to in food changing the look, smell and taste of food. can have fuzzy appearance

yeast- grown on surfaces of foods. ferments sugars turning them into alcohol and carbon dioxide.

Question 10

What temperature should you heat food to to kill bacteria?

Answer 10

75 degrees

Question 11

What us the danger zone for bacteria to grow?

Answer 11

5 to 63 degrees

Question 12

What is the optimal temperature for bacteria to grow in?

Answer 12

37 degrees

Question 13

What temperature should foods be chilled and frozen at?

Answer 13

chilled at 0 to 5 degrees
frozen at minus 18 degrees as bacteria will become dormant and stop growing

Question 14

What shelf should meat and poultry be kept on?

Answer 14

bottom shelf to prevent dripped of blood and juices of raw meat

Question 15

What are ambient foods?

Answer 15

foods that can be stored safely at room temperature but should still be kept in a sealed container

Question 16

What are 4 methods of preservation of food?

Answer 16

freeze-drying -removes moisture from food

canning foods- sealed in cans and heated to kill microorganisms

vacuum packing- plastic packaging with air sucked out

using chemicals- gherkins are put into vinegar which make it too acidic for microorganisms to grow

Question 17

What is the use by date?

Answer 17

-date shown for products with a short shelf life
-given as safety warning of food poisoning

Question 18

What is the best before date?

Answer 18

-date shown on products with a lower shelf life
-given as warning about quality of food but can be eaten after the best before date

Question 19

What is cross-contamination?

Answer 19

when bacteria is passed onto food

Question 20

What sources can cross contamination occur from?

Answer 20

-other contaminated food
-utensils, equipment, work surfaces
-people (poor personal hygiene or coughing and sneezing
-pests (flies, rodents)

Question 21

How should you prepare food to avoid cross-contamination?

Answer 21

-follow personal hygiene procedures
-separate raw and cook foods
-use coloured chopping boards
-use clean equipment

Question 22

How should you cook food to avoid cross-contamination?

Answer 22

-cook at right temperatures
-make sure food is cooked all the way through
-test temperature of food using a probe

Question 23

How should you serve food to avoid cross-contamination?

Answer 23

-serve hot food right away
-if you’re storing foo cold do it within 90 mins
-keep food covered to prevent pests

Question 24

What are the general symptoms of food posioning?

Answer 24

sickness, diarrhoea, stomach cramps and fever

Question 25

What is campylobacter bacteria?

Answer 25

-most common cause of food poisoning in the uk
- found many in undercooked or raw meat
-onset time of 2 to 5 days

Question 26

What is E.coli bacteria?

Answer 26

-live in intestines of animals
-version o157 can cause kidney damage and death
-found in raw beef, untreated milk/ water, unwashed veg and salad leaves
-onset time of 1 to 10 days

Question 27

What is salmonella bacteria?

Answer 27

-found in raw poultry, untreated milk and eggs
-onset time of 6 to 72 hours

Question 28

What is Staphylococcus bacteria?

Answer 28

• staphylococcus aureus lives on the skin, hair and noses of animals and people
• caused by poor personal hygiene
  -onset time of 1 to 6 hours

Question 29

What is Listeria bacteria?

Answer 29

• can be found in soft cheeses, pate and shellfish
• can grow in cold temperatures like a fridge
  -can lead to miscarriage or health problems in child
  -onset time of up to 70 days

Question 30

What are methods for controlling bacteria?

Answer 30

pasteurisation- milk is heated at 72 degrees for 15 secs to kill off any pathogenic bacteria before being chilled

vaccinations- British Lion Quality mark egg shells and boxes to say if they have been vaccinated against salmonella

Question 31

Some moulds are safe to eat, what is an example of this?

Answer 31

blue bits on blue cheese, give cheese a creamy texture and distinctive sharp and tangy taste

Question 32

Which microorganism is good for baking?

Answer 32

yeast

Question 33

How is bacteria used to make yoghurt and cheese?

Answer 33

1. Milk is pasteurised to kill off any ‘bad’ bacteria.
2. Non-pathogenic bacteria are added fermenting lactose and producing lactic acid.
3. The lactic acid acts on the proteins in the milk to thicken it and gives it a sour or tangy taste.
   4.Probiotics (live bacteria) are a supplement in some yoghurts which are said to give health benefits.