Recap food production
• Why are plants so important in the production of
food?
• List the 3 stages of selective breeding
• Which types of chemicals are used to improve
food production
• Choose one type and explain how its use would
increase yield.
Objectives
• Describe the spoilage of food due to
microorganism contamination
• Identify treatments used to prevent food spoilage
• Evaluate the these treatments
Microorganisms and food
• http://www.youtube.com/watch?v=S12zZhdO
ckc
• http://www.youtube.com/watch?v=yFIqj0DM
Fow&feature=related
Visible growth
• Most obvious with fungi E.g. black Mucor and
blue/green Penicillium moulds
External digestion
• Release of enzymes to break down food so it can be
absorbed by the microorganism
• Often smells sweet
• Eventually reduced to mush
Toxin production
• Some microorganisms
produce toxins
• E.g. Clostridium
botulinium produces
toxin so toxic that 1µm
will kill a human
Infection
• Microorganisms in food
can cause infection
(food poisoning)
• E.g. Salmonella
•
http://www.youtube.com/watch?v=gEwzDydciWc
Conditions required for growth
• Organic food - proteins, fats, carbohydrates
• Suitable temperature
• Water
• Oxygen (in some cases)
• Suitable pH
Food treatment
Cooking
Pasteurising
Drying, salting, sugar coating
Smoking
Pickling
Irradiation
Cooling/freezing
• http://www.food.gov.uk/safereating/rad_in_f
ood/irradfoodqa/
Prevent further contamination
• Canning
• Vacuum packing
• Packaging
Objectives
• Describe the spoilage of food due to
microorganism contamination
• Identify treatments used to prevent food spoilage
• Evaluate the these treatments