Microorganisms and Food
Bread - the yeast turns to carbon dioxide and ethanol. The CO2 makes the bread rise.
Wine - yeast turns the sugar in the grape to ethanol (alcohol) and C02.
Cheese - bacteria turns the sugar in the milk to lactic acid which causes the milk to curdle.
- grow rapidly under the right conditions - quick food production
- grow on a range of inexpensive materials
- environment can be artificially controlled - can be grown anywhere
- conditions for growth are easy to create
- can last longer in storage than the raw product they're made from.
- there's a high risk of food contamination as conditions are favourable to harmful microorganisms
- small changes in temperature or pH coulf kill the microorganisms
Prevention of Spoilage
- Salt inhibits the growth
- interferes with the ability to absorb water
- water moves down concentration gradient into the salt
- same as salting
- slows down the reactions taking place in microorganisms
- freezes the water in the food so microorganisms can't use it
- vinegar has a low pH which reduces enzyme activity
- this inhibits their growth
- kills any microorganisms present
- involves exposing foods to radiation
- X-rays or Gamma Rays
- kills any microorganisms present.