Microorganisms in Food
Biology: Edexcel IGCSE, topic 6.1.5
Microorganisms in Food
The products of anaerobic respiration of bacteria and yeast are used to make certain foods.
Yeast
- In yeast cells, glucose is converted into ethanol and carbon dioxide.
- Glucose → ethanol + carbon dioxide
- This is called fermentation. The carbon dioxide produced causes the size of bread dough to increase while it is ‘proving’ during bread making.
Bacteria
- A type of bacteria called Lactobacillus respire a sugar called lactose in milk to produce lactic acid.
- Lactose → lactic acid
- This lactic acid turns the milk into yoghurt, giving it a sour taste and thicker texture.
Test yourself on Microorganisms in Food
What are the products of anaerobic respiration in yeast?
Which bacteria are needed to make yoghurt?