Food Spoilage And Contamination Flashcards
What are the four ways food can spoil?
Moulds
Yeast
Bacteria
Enzymic browning
When do the enzymes in food react with oxygen?
When they are bruised or cut open
What causes overripening in fruits?
Enzymes
What foods do yeasts mostly grow on?
Acidic and sweet foods
What does yeast produce when it ferments the sugar in food?
Alcohol and carbon dioxide
What conditions do moulds grow in?
Moist
Warm (they can grow in cold conditions given time)
Why is it important to sterilise jam hars before use?
The boiling process destroys mould in jam, but if they aren’t sterilised mould spores can grow in the jam
When should you put the lid on homemade jam and why?
Either as soon as the jam is made or once the jam has completely cooled so condensation doesn’t form on the lid and dilute the sugar on the surface, allowing mould to grow
Why can you just scrape mould off food?
Moulds grow throughout the food to extract nutrients from it
What are yeasts?
Tiny single celled fungi
Microorganisms
What are moulds?
Tiny fungi that produce spores
Microorganisms
What are enzymes?
Biological catalysts
What is pasteurisation?
Heat treatment that kills most microorganisms in food
What is sterilisation?
Something is heated to kill bacteria yeasts and moulds
Whatvare mould spores?
Spores produced by mould that help it spread
How does yeasts spoil food?
They change the texture taste smell or colour of the food by fermenting the sugar
How is yeast used in food production?
It is used as a raising agent and in the brewery industry
How is mould used in food production?
To improve the colour and flavour of cheese
Ripen the surface of sausages and improve their smell and shelf life
How is bacteria used in food production?
Making cheese and yogurt
What are the raw ingredients for making cheese?
Milk
Rennet
Salt
A starter culture of bacteria
Why is milk used for cheese making pasteurised?
To kill harmful bacteria
Explain the steps of cheese making
pasteurised milk is warmed
The starter bacteria culture is added to sour it
Rennet is added to increase the rate of curdling (separate into curds and whey)
These are then cut to release the way and drain it
The curd is heated, stirred, and milled to form small pieces.
Salt is added to help flavour and preserve the cheese
The curd is pressed into moulds to make blocks of cheese
It then goes into cool storage