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?
temperature
air/oxygen
microorganisms
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?
Wrap foods that aren’t already
The top shelf is most likely the warmest
Door shelves are warmer than other parts
Food should be refrigerated for short amounts of time
Let hot foods cool before putting them in the fridge
Try not to open and close the fridge door a lot.
Fridges should be cleaned out regularly
Keep raw meat covered and on the bottom shelf
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?
Clean and disinfect the probe before use
Insert the probe to the centre or thickest part of the food
Wait a few seconds for the display to stabilise before taking a reading
Read the temperature
Check the food has reached 75 C
Clean and disinfect the probe after use