Lactobacillus bacteria are used in the commercial production of yoghurt from milk.
Name the kingdom of organisms that includes Lactobacillus.
What is meant by the term anaerobic?
Write the word equation for anaerobic respiration (fermentation) in these bacteria.
During yoghurt production, the milk is pasteurised and the fermentation vessels are sterilised. Describe one method, other than heating, that can be used to sterilise the equipment.
Why is it important to use sterilised equipment?
The primary carbohydrate source in milk is lactose. Name the enzyme that digests lactose.
Name the two simple sugars produced when lactose is digested.
During yoghurt fermentation, the number of live Lactobacillus cells initially increases, but eventually decreases towards the end of the process. Explain why the number of live bacteria decreases towards the end of the process.
74 exam-style questions on Edexcel IGCSE Biology Food production. Each one has a worked solution and a mark scheme showing where the marks go.