Two different strains of Lactobacillus bacteria, strain AAA and strain BBB, are used in the commercial production of yoghurt from milk. During fermentation, these bacteria convert lactose into lactic acid, which lowers the pH and clots the milk proteins.
Design an investigation to determine which strain of Lactobacillus is most rapid at fermenting milk. Your answer should include experimental details and be written in full sentences.
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.