Outline the role of microorganisms in the production of yoghurt.

Mark scheme

Marking points from the official mark scheme (May/June 2015). The mark or mark type is shown in brackets.

1. [max 6] (a) 1. bacteria (or named e.g. Lactobacillus) ;
2. [max 6] (a) 2. milk ;
3. [max 6] (a) 3. incubation / 32 – 50 °C ;
4. [max 6] (a) 4. reproduction of bacteria ;
5. [max 6] (a) 5. ref. to enzymes / lactase ;
6. [max 6] (a) 6. sugar / lactose ;
7. [max 6] (a) 7. to lactic acid ;
8. [max 6] (a) 8. coagulation / curdling of + milk / protein / casein ;
9. [max 6] (a) 9. imparts texture / flavour ;
10. [max 4] (b) 1. spores ;
11. [max 4] (b) 2. produce hyphae/mycelium ;
12. [max 4] (b) 3. enzymes ;
13. [max 4] (b) 4. ref. suitable temperature ;
14. [max 4] (b) 5. external digestion/description of ; A saprotrophic/saprophytic
15. [max 4] (b) 6. of starch ;
16. [max 4] (b) 7. of protein ;
17. [max 4] (b) 8. soluble/diffusible OR named ; A simple sugars
18. [max 4] (b) 9. ref. (fungal) respiration ; Ig refs to anaerobic