Food spoilage Flashcards
When do you know your food is spoiled?
The original nutritional value, texture, flavour or appearance is damaged/changed.
Perishable foods?
Spoils in 1-3 days at room temp.
Semi perishable foods?
Spoil in 4 – 10 days at room temperature
Non-perishable foods?
Can last longer than 2 weeks at room temperature
Enzymes:
a chemical that speeds up the process of decay by
breaking down food, e.g., rottening of fruit and vegetables.
Oxidation:
the chemical reaction that takes place between food and the oxygen in the
air e.g., discolouration of an apple or potatoes when cut or peeled and not
put it in water.
A Moisture loss
Fruits/vegetables wither. When food dries out.
Moisture is absorbed
potato chips, bread or cookies get mushy
How to prevent microorganisms from multiplying?
Use high temperatures to destroy.
* Use low temperatures to control growth
* Prevent contamination.
* Use preservatives (salt, sugar and vinegar) to inhibit growth.
Mould?
Moulds are tiny plants that grow on sweet foods, fresh fruit,
vegetables and cereal products. Grow on the outer part of the food, when cut away you can eat the rest of the food product
Yeasts?
Microscopic single celled fungi
* Found in the air, soil and on surface of fruits.
* They feed on flour or sugar in food to produce carbon dioxide and
alcohol (fermentation).
PATHOGENES
❖ Not always easily observable in food
❖ May sometimes be slimy / smell bad
❖ Bacterial spores survive in adverse
conditions, so they survive in very
cold or very hot temperatures.
❖ Possible symptoms
* Nausea
* Braking
* Diarrhoea
* Stomach cramps
FACTORS AFFECTING BACTERIA GROWTH
RATE:
➢ Food type / composition of food
➢ Moisture quality of food
➢ Time exposed
➢ Acid content
➢ Temperature
EFFECTS OF PATHOGENS ON FOOD.
Signs of decay
* Smell
* Mucus
* Discoloration
* Gas
GUIDELINES FOR PEST CONTROL
- Store food in airtight plastic, metal or glass containers
- Keep the kitchen clean
- Cover all food - do not leave it open overnight
- Remove dirt and food from drains
- Garbage can must be properly sealed
- Take rubbish out of the kitchen every day
- Remember that prevention is the best way to fight pests