Food Safety
Moulds. Not all moulds are harmful. Some are used in food manufacture to produce specific flavours and textures. Moulds are visible to the eye. They reproduce by producing spores which travel in the air and settle, germinate and multiply into new growths. They are harmful only when they produce mycotoxins which are poisonous substances.
Conditions needed for growth for mould.
They grow quickly in moist conditions 20-30 degrees C.
They grow slowly in dry, cold conditions.
They grow on food that may be dry, moist, acid, alkaline or has high salt or sugar concentrations.
Yeasts. Through the process if fermentation, yeasts are used to make bread and alcohol. Yeasts are responsible for food spoilage in high sugar foods such as fruit, jam and fruit yoghurts.
Conditions needed for growth for yeasts.
Active in warm, moist conditions with food for growth and reproduction.
Does not need oxygen to grow, anaerobic.
Bacteria. Not all bacteria are harmful. Harmful bacteria are known as pathogenic bacteria.
Conditions needed for growth for bacteria.
Need warmth, moisture, food and oxygen.
Reproduce by dividing in two, binary fission.
Grow rapidly in neutral pH conditions.
Are most active in a temperature range of 5-65 degrees C, the danger zone.
Become dormant below 0 degrees C.
Most cannot survive above 70 degrees C.
Are able to form spores that are dormant, they will germinate when the right conditions are provided.
Can grow aerobically and anaerobically.
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If food is not stored correctly, it will become unfit to eat. Changes are caused by yeasts, mould and bacteria.