Section 3- Food safety

Question 1

What are examples of microorganisms?

Answer 1

bacteria, moulds and yeasts

Question 2

What are the 5 conditions microorganisms need to grow and multiply?

Answer 2

warm temperature, moisture, food, pH, time

Question 3

What conditions could you change to slow or stop the growth of microorganisms?

Answer 3

• use a fridge to change temperature
• pickle the food in vinegar to change the pH
• add salt (salt absorbs water which removes the moisture from the food)

Question 4

What are high risk foods?

Answer 4

ready-to-eat foods that if not stored correctly could grow harmful bacteria

Question 5

What are some examples of high risk foods?

Answer 5

cooked meats, fish and poultry, dairy products, gravies, stocks, shellfish

Question 6

Why isnt chicken classed as a high risk food?

Answer 6

chicken might have lots of bacteria but its not classed as a high risk food because you dont eat it raw
- once its cooked and “ready to eat” it can be described as high risk

Question 7

What is an examples of how you can identify when a high risk food is spoiling?

Answer 7

• meat going slimy, milk smelling sour or cheese going mouldy

Question 8

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

Answer 8

• fresh meat should be brightly coloured, firm and have a fresh smell
• fresh fish should have shiny skin, red gills, clear eyes and smell clean or slightly salty

Question 9

What are enzymes?

Answer 9

• special proteins that act as biological catalysts
• they speed up chemical reactions

Question 10

How can you see the effects of enzymes during ripening?

Answer 10

• enzymes in fruit cause them to ripen which affects the sweetness, colour and texture of the fruit

Question 11

How can you see the effects of enzymes during browning?

Answer 11

• when you slice fruits the oxygen in the air will turn the fruit brown
• enzymes in the fruit speed up this process

Question 12

How can you have control over the activity of enzymes?

Answer 12

adding an acid- enzymes work better at a certain pH, if you dip slices of fruit into lemon juice, the acidic conditions will stop

enzyme browning
blanching- (plunging in boiling water for a short period), used to prepare veg for freezing. Natural ripening enzymes will cause the veg to lose colour, texture and flavour. Freezing will slow the enzymes but not stop the completely - blanching destroys ripening enzymes

Question 13

What do moulds spoil?

Answer 13

bread, cheese and fruit

Question 14

Where do yeasts grow?

Answer 14

on the surface of fruit such as grapes, blackberries and tomatoes

Question 15

How can yeasts spoil fruit?

Answer 15

by fermenting the sugars turning them into alcohol and carbon dioxide

Question 16

What happens when you cook/reheat food to 75 degrees?

Answer 16

• cooking food above 75 degrees bacteria
• its important to reheat properly and only one
• check its at least 75 degrees with a temperature probe

Question 17

What happens during the danger zone (5 degrees-63 degrees)?

Answer 17

• bacteria can grow and multiply quickly in temperatures from 5 degrees to 63 degrees
• optimum temperature for bacteria growth is 37 degrees

Question 18

What happens during chilling (0 degrees - 5 degrees)?

Answer 18

• keeping food between 0 degrees and 5 degrees slows down the growth of bacteria
• extends shelf life of the food
• chilling food doesn’t change its properties much (may have a harder texture)

Question 19

What happens during freezing (-18 degrees)?

Answer 19

• stops bacteria growing
• bacteria becomes dormant
• greatly extends the shelf life of the food and the nutrients are not lost
• doesn’t kill bacteria, they become active again when the food defrosts

Question 20

How can you use a fridge correctly?

Answer 20

• fridges should be kept between 0-5 degrees ideal for chilling foods
• keep food covered or stored in contains to prevent contaminating other foods
• dont led blood and juices of raw meat drip onto other food (always store at the bottom of the fridge)

Question 21

How can you use a freezer correctly?

Answer 21

• set around -18 degrees
• food should have clear labels with the date they were frozen
• defrost meat and poultry thoroughly in a fridge
• if the food is partially frozen the recommended cooking time may not be sufficient to kill bacteria

Question 22

What is the star rating on freezers and frozen foods to indicate when how long to store food?

Answer 22

storing in an ice box/freezer compartment in fridge- 1 week at -6 degrees, 1 month at -12 degrees

stored in a domestic freezer- 3 months at -18 degrees and until best before date -18 degrees or colder

Question 23

What are ambient foods?

Answer 23

foods that can be safely stored at room temperature

Question 24

What are some examples of ambient foods?

Answer 24

crisps, tinned vegetables, bread, pasta, cereal

Question 25

How should ambient foods be stored?

Answer 25

stored in a sealed container - keeping the air out keeps the food fresh

Question 26

What are the methods of preservation that can be used to extend the shelf life of ambient foods?

Answer 26

freeze drying- removes moisture from the food canning foods- foods are sealed in cans and heated to kill of microorganisms vacuum packing- food is put into plastic packaging and the air is sucked out using chemicals- gherkins are pickled in vinegar, making it too acidic of microorganisms to grow rapidly

Question 27

What is the use by date?

Answer 27

- shown on products with a short shelf life e.g high risk foods - given as a safety warning, if you use food after this date it might not be safe so you run the risk of getting food poisoning

Question 28

What is the best before date?

Answer 28

- shown on products with a longer shelf life e.g tinned foods - given as a warning about quality, if you eat the food after this date its probably safe but may not be as nice as you would expect - eggs however are risky to eat after their best before date as salmonella bacteria have multiplied to dangerous levels

Question 29

How can cross contamination happen from a variety of different sources?

Answer 29

other contaminated food - raw meat juices can drip onto cooked food, high risk foods such as gravy can contaminate lower risk foods when added to a metal utensils, equipment and work surfaces- using unclean equipment, dirty clothes on work surfaces or the same work surface, chopping board for raw meat separate to veg people- poor personal hygiene, sneezing or coughing pests- flies contaminate food by directly walking over, laying eggs

Question 30

What steps should you take to reduce the risks when preparing food?

Answer 30

- follow personal hygiene procedures- wash your hands, wear a clean apron, hair net - separate raw and cooked foods using coloured chopping boards - wash raw veg - use clean equipment and anti bac spray on surfaces - de frost frozen food fully in the bottom of the fridge

Question 31

What steps should you take to reduce the risks when cooking food?

Answer 31

- cook food at the right temperature and for the correct time - food is cooked all the way through (cook thicker pieces of meat for longer than thin ones) - test temp inside food using a temperature probe

Question 32

How do you use a temperature probe?

Answer 32

- sterilise the probe before and after use - insert it into the middle of the thickest part of the food - leave the probe until the temp stabilises - check the probe reaches 75 degrees

Question 33

What steps should you take to reduce the risks when serving food?

Answer 33

- serve hot food straight away or keep it above 63 degrees for no longer than 6 hours - if your serving food cold or storing it cool it down within 90 mins - keep food covered to prevent flies or pests contaminating - avoid wasting food, check waste bins are not overfilled

Question 34

What are general symptoms of food poisoning?

Answer 34

sickness, diarrhoea, stomach cramps, fever

Question 35

What is Campylobacter?

Answer 35

- most common - food mainly in raw or undercooked poultry but also in other raw meat - onset time is 2-5 days

Question 36

What is salmonella?

Answer 36

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

Question 37

What is E-coli 0157?

Answer 37

- e coli live in the intestines of animals - most types are harmless but e coli can cause kidney damage and death sources include raw beef, untreated milk/water - onset time 1-3 days

Question 38

What is Staphylococcus aureus?

Answer 38

- found on the skin, hair and in the noses of animals and people - onset time is 1-6 hours

Question 39

What is onset time?

Answer 39

the time it takes from ingesting the bacteria to when symptoms first appear

Question 40

What is Listeria?

Answer 40

- found in soft cheeses, shell fish - grow in cold temperatures like refrigerators - pregnant women at a higher risk of infection, can lead to miscarriage onset time is up to 70 days

Question 41

What methods are in place to make foods that are contaminated with bacteria safe to eat?

Answer 41

pasteurisation- all the milk solid in supermarkets is pasteurised. milk is heated at around 72 degrees for 15 seconds to kill off any pathogenic bacteria before being chilled vaccinations- british lion quality mark on egg shells and boxes is for hens that have been vaccinated against salmonella, so that it doesnt contaminate their eggs

Question 42

Which cheese is safe to eat?

Answer 42

- blue bits on blue cheeses are due to moulds that have been added to them - mould gives the cheese a creamy texture and a distinctive sharp, tangy taste

Question 43

How does the production of many varieties of bread rely on the properties of yeast as a raising agent?

Answer 43

- yeast, flour and water form a dough - salt is added for flavour but also to strengthen the gluten in the dough - with the ideal conditions the yeast starts to grow - yeast ferments the sugar to produce carbon dioxide - this gas is what causes the bread to rise

Question 44

How is bacteria used to make yogurt?

Answer 44

- milk is pasteurised to kill off any bad bacteria - non pathogenic bacteria are added - these bacteria ferment lactose and produce lactic acid - the lactic acid acts on the proteins in the milk to thicken it and gives it a sour or tangy taste - probiotics (live bacteria) are supplement in some yogurts which are said to give health benefits