Food spoilage (will come up) Flashcards
Ways of storing foods to prevent spoilage
In the fridge at 5C
Keep food covered
Don’t let blood or juices drip onto other food
Pickle the food in vinegar to change the pH
Add salt - salt absorbs water causing it to dry out
Can the food
Make a jam
Freezer -18
Clear labels of when frozen
Conditions needed for microorganisms to grow
Warm temperature Plenty of moisture Plenty of food The right pH Time
Use by date
It’s shown on products with a short shelf life eg high risk foods
Its a safety warning, if you use the food after this date, it might not be safe - could cause food poisoning
Best before date
Shown on products with a long shelf life eg tinned foods
Its given as a warning about quality
If you eat food after this date its probably safe but might not be as nice eg biscuits could be soft
How to slow or stop an enzyme from working
Add an acid - enzymes work best at a certain pH
Eg dip fruit into lemon juice, will stop enzymic browning
Blanching -destroys the ripening enzymes so vegetables retain colour and nutrients
Freezing slows down enzymes
How does mould and yeast spoil food
They are both microorganisms, in the right conditions they can grow and spread quickly
Moulds spoil cheese, bread and fruit - they change the look, smell and taste of food
Waste products from mould can cause food poisoning - toxins
Yeasts commonly grow on the surfaces of fruit and spoilt it by fermenting the sugars into alcohol and carbon dioxide
Mould and yeast growth can be prevented by correctly storing food eg bread in dry, cool conditions and fruits in fridge
Signs of food spoilage
Meat - slimy
Milk - sour
Cheese - mouldy
What can cause cross-contamination
Other contaminated food - raw meat juices can drip onto cooked food
Utensils, equipment and work surfaces - unclean equipment, dirty cloths or the same work surface - chopping board used for raw meats and ready to eat foods
People - poor personal hygiene - unclean hands, sneezing, coughing
Pests - flies, rodents can contaminate food by walking on it eating it, laying eggs or droppings on surfaces
How is jam made and food pickled
Jam - fruit is boiled with sugar and pectin, and sealed in a glass jar (high sugar)
Pickle - food is plunged into brine or vinegar (too acidic)
How is food vacuum packed, bottled and freeze-dryed
Vacuum - food is put into plastic packaging and the air is sucked out
Bottled - food is sealed in a can or jar and heated
Freeze-drying - food is frozen and dehydrated to remove moisture
Salmonella, found, symptoms, time
Found in raw poultry, untreated milk and eggs
Diarrhoea, stomach cramps and vomiting
Onset time 6-72 hours
Campylobacter found, symptoms, time
Raw or undercooked poultry, other raw meat, untreated milk or water
(bloody) diarrhoea, stomach cramps, fever
2-5 days
E coli found, symptoms, time
Found in intestines of animals and can contaminate raw beef, untreated milk/water, unwashed veg
Cause kidney damage and death
1-3 days
Staphylococcus aureus found, symptoms, time
Lives on the skin and hair and in noses of people and animals
Poor personal hygiene
Diarrhoea, stomach cramps, vomiting, mild fever
Onset time 1-6 hours
