Kefir is a nutritious fermented milk drink made using kefir grains, which contain a symbiotic mixture of lactic acid bacteria and yeasts.
Explain why milk is heated to a high temperature (pasteurised) at the start of the kefir-making process.
The pasteurised milk is cooled to a warm temperature before the kefir grains are added. Explain why this cooling step is necessary.
Kefir is often fortified with vitamins. Give one benefit of including Vitamin B12 in the diet.
Skimmed milk kefir is a popular dietary choice. Give one benefit of choosing skimmed milk kefir over whole milk kefir.
Explain why the fermentation process by the kefir grains causes the mixture to become slightly acidic (lower pH) and carbonated (fizzy).
Some manufacturers add chia seeds to kefir. Suggest the health benefits of adding chia seeds to kefir.
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.