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=S12zZhdOckc

• http://www.youtube.com/watch?v=yFIqj0DMFow&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 treatmentCookingPasteurisingDrying, salting, sugar coatingSmokingPicklingIrradiationCooling/freezing

• http://www.food.gov.uk/safereating/rad_in_food/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