Microorganisms and enzymes

pg 75 revesion booklet

what micro organisms are

what micro organisms are

• tiny plants and animals

• also called microbes

• very small

  • only visible under a microscope

What they are called

Bacteria, mould, yeasts

there are many diffrent types of each

where they come from

air water soil dust food sweage clothes

what they do to food

• live on/ in food where they grow and multiply

  • if the food is stored, handled , cooked properly this prevents them from multiplying

what makes them grow and multiply

• they need:

  • right temp

  • enough moisture

  • food to eat

  • time to grow

  • right ph

how to prevent microbes from growing and multiplying

• cooking at at least 75 degrees will kill the microbes

• if put in a fridge with at least - 0.5 it slows down growth and multiplication

• if temp reaches -18 microbes become in active but still alive

• if u remove misture (dried foods) they die completely

• if you cover food and store it corectly this prevents microbes from contact

• some microbes are killed by:

  • acids (vinegar in pickles)

  • high salt levels

    • dried salted fish

  • sugar

    • jam

why they make food unsafe and unfit to eat

• put waste products and poisons on/in trhe food

  • if eaten causes food poisoning

• large numbers cause ill ness as they irritate the digestive track

• not all make microbes make u ill

  • some are needed for food prduction

    • e.g. yeast to make bread, bacteria to make yogurt

• microbes that make you ill are called pathogenic (harmful) microbes

microrganisms

tiny plants and animals that grow and multiply when right conditions are met

only visible under a miroscope

pathogenic

something that is capable of causing illness in people

contaminate

making a food unsafe to eat by allowing it to come in contact with micro organisms that will grow and multiply in/on it

food poisoning

an illness caused by pathogenic micro-organisms that have contaminated some food

e.g. salmonella in undercooked chicken

high risk foods

foods that contain a lot of moisture and protein

they easily allow pathogenic microorganisms to grow and multiply, paticularily bacteria

also called perishible foods

e.g. milk eggs cream meat fish

low risk foods

foods that contalin low moisture

high in acids or sugars and salt

also called non perishible foods or dried foods

its hard for pathogenic microbes to grow on them

e.g. pasta rice flour