Useful and Harmful Microbes — Science STD 9 — Question
Maharashtra BoardEnglish MediumSTD 9ScienceUseful and Harmful Microbes3 Marks
Question
Lactobacilli are used for making yoghurt from milk.
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Answer
Lactobacilli convert lactose, the sugar in the milk, into lactic acid. This process is called fermentation.
As a result, the pH of milk decreases causing coagulation of milk proteins.
Thus, milk proteins are separated from other constituents of milk and milk changes into yoghurt.
Yoghurt has a specific sour taste due to lactic acid. The low pH destroys harmful microbes present in the milk. Therefore, Lactobacilli are used for making yoghurt from milk.
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