2.4.3 - Micro organisms and food

Examples of how micro organisms can be used to make food: 

• Bread- Made by mixing yeast, sugar, flour and water into a dough. The yeast turns the sugar into ethanol and carbon dioxide. It is the carbon dioxide that makes the bread rise
• Wine- Is made by adding yeast to grape juice. The yeast turn the sugar in the grape juice into ethanol and carbon dioxide
• Cheese- Made by adding bacteria to milk. The bacteria turn the sugar in the milk to lactic acid, which causes the milk to curdle. An enzyme is then used to turn the curdled milk into curds and whey. Curds are separated off and left to ripen into cheese 
• Yoghurt- Also made by adding bacteria to milk. The bacteria turn the sugar in the milk to lactic acid, causing the milk to clot and thicken into yoghurt

Advantages of the process:

• Populations of micro-organisms grow rapidly under the right conditions, so food can be produced quickly
• Micro-organisms can grow on a range of inexpensive materials 
• Their…