Food safety

outline the characteristics of enzymes

outline the characteristics of enzymes

• Enzymes cause food spoilage

• they are catalysts for chemical reactions

• they cause browning in certain foods called enzymic browning

• enzymes can be destroyed by heat or acid

• They cause food to spoil by oxidation

how can you prevent oxidation when cooking?

• adding an acid

• cooking immediately

• protect from light

• add antioxidants

• refrigeration

what is needed for food spoilage to occur?

1. temperature

2. air/oxygen

3. microorganisms

4. enzymes

outline the characteristics of yeast

• they prefer acidic foods

• As yeasts ferment the sugars in these foods , they produce alcohol and carbon dioxide

• can grow with or without oxygen

• Spoil fruit, juices, jam and honey

outline the characteristics of moulds

• grow best at 20-30 C

• damp air and warm temperature can speed up mould growth

• they grow throughout the foods to get all the nutrients

• grow easily on bread, cheese, jam, and soft fruits

what are the groups of bacteria?

• Harmless bacteria

• Pathogenic bacteria

• Food spoilage bacteria

how are moulds used in food production?

To make cheese: Starter culture is added to change lactose to lactic acid. This gives the correct level of acidity and gives the cheese moisture. The mould gives the cheese a smell, taste and texture.

To make yogurt

how is yeast used in food production?

To produce bread, beer and wine.

Yeast ferments or breaks down glucose into alcohol and carbon dioxide.

how is bacteria used in food production?

Making cheese: Starter culture is added to ripen the cheese and creates curds and whey.

how is mould used in cheese production?

To make blue cheese: creates blue veins within the cheese

To make soft ripened: mould grows on the outside causing the cheese to age from the outside in

what are the sources of bacterial contamination?

• raw food

• dirty work surfaces and equipment

• food handler

• waste food

• pet contamination

• rubbish contamination

what are some examples of pathogenic bacteria?

• campylobacter

• E.coli

• Salmonella

• Listeria

• Staphylococcus aureus

what food is linked to campylobacter?

Raw poultry, meat and milk

what food is linked to E.coli ?

Under-cooked meat

what food is linked to Salmonella?

Bean sprouts, unpasteurised milk, imported poultry and eggs

what food is linked to listeria?

Soft cheese, cooked chicken and salad vegetables

what food is linked to Staphylococcus aureus?

Food that is prepared by an infected person and eaten raw

what is the temperature danger zone?

63 - 5 C

define ‘non-perishable food’

Food that cannot go off

what is ambient temperature?

Room temperature. 17-20 C

define ‘best before’

a recommendation on how long you have until the food won’t taste its best

define ‘use by’

Dates which are on food indicating it may be unsafe to eat after this date

what are some tips when using a fridge?

1. Wrap foods that aren’t already

2. The top shelf is most likely the warmest

3. Door shelves are warmer than other parts

4. Food should be refrigerated for short amounts of time

5. Let hot foods cool before putting them in the fridge

6. Try not to open and close the fridge door a lot.

7. Fridges should be cleaned out regularly

8. Keep raw meat covered and on the bottom shelf

9. Drinks and milk should be kept in the door.

what are personal hygiene rules for the kitchen?

• Hair up

• Wash hands

• Sleeves rolled up

• Don’t touch your face

• Cover cuts

• Gloves,mask

• Hair/beard net

• Apron

• No jewellery

how do you use a food thermometer probe?

1. Clean and disinfect the probe before use

2. Insert the probe to the centre or thickest part of the food

3. Wait a few seconds for the display to stabilise before taking a reading

4. Read the temperature

5. Check the food has reached 75 C

6. Clean and disinfect the probe after use