Lesson eLearning

In a dairy industry, probiotic strains *Lactobacillus rhamnosus* and *Bifidobacterium lactis* are used as starter cultures. Which of the following statements about their role is NOT true?

medium MCQ 3 marks Class 12 · Biology · Microbes in Human Welfare
  1. They ferment lactose to produce lactic acid.
  2. They enhance the shelf life by lowering pH.
  3. They produce bacteriocins that inhibit pathogenic bacteria.
  4. They increase the water content of the final product.
Answer
They increase the water content of the final product.

The correct answer is They increase the water content of the final product. — Conclusion: Option D is the incorrect statement.

Step-by-step solution

  1. Identify functions of probiotic starters: fermentation of lactose to lactic acid, lowering pH, inhibition of pathogens via bacteriocins, and improving texture.
  2. Examine each option:
  3. Option A: They ferment lactose to produce lactic acid – true.
  4. Option B: They enhance shelf life by lowering pH – true.
  5. Option C: They produce bacteriocins that inhibit pathogenic bacteria – true.
  6. Option D: They increase the water content of the final product – false, as they do not add water.
  7. Conclusion: Option D is the incorrect statement.
Common mistake: Assuming probiotics add moisture to the product

Concept tested: Role of probiotic starters in dairy

Published · How this solution was prepared and checked

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