PRODUCTION OF YOGHURT

Again, as, with brewing, only the role of the organisms in the production process is specifically required.

It is suggested that students should recall


Many teachers, especially if wishing to make yoghurt as a practical activity, will examine the overall commercial process with their students

Flow chart for commercial production of stirred yoghurt

Heat milk to 85-95C for 15-30 minutes

v

Homogenise the milk


v

Cool the milk to incubation temperature

v

Add the bacterial starter

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Incubate the mixture at 40-46C for 4-5 hours

(until the pH has fallen to around 4.3)

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Stir the thickened yoghurt and cool it to 5C

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Add fruit, flavourings, colorants (if required)

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Pack and despatch the yoghurt, keeping it refrigerated

Presented with such a flow chart in the examination, candidates might be asked questions such as:

Explain how bacteria, apart from those in the starter, are prevented from growing in the milk.

Why is the milk cooled before the starter is added?

How does bacterial activity give yoghurt its sour flavour?

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