Life Sciences: Biology and Human Health› Microbiology: Viruses, Bacteria, Fungi and Useful Microbes
Consider the following statements in respect of probiotics:
- 1. Probiotics are made of both bacteria and yeast.
- 2. The organisms in probiotics are found in foods we ingest but they do not naturally occur in our gut.
- 3. Probiotics help in the digestion of milk sugars
Which of the statements given above is/are correct ?
Answer c.
Option (c) — statements 1 and 3 only. Probiotics do include yeasts as well as bacteria and do help break down lactose, but the whole point of them is that the same or similar organisms already live naturally in our gut. Probiotics are live micro-organisms that confer a health benefit when taken in adequate amounts; the common ones are bacteria (Lactobacillus, Bifidobacterium) but the yeast Saccharomyces boulardii is a well-established probiotic too, so statement 1 holds. Statement 2 fails on its second half: probiotic strains are chosen precisely because they resemble the resident gut flora, which is why they can colonise and survive there. Statement 3 is standard biology — lactic acid bacteria carry beta-galactosidase (lactase), which hydrolyses lactose, and probiotic-rich curd/yogurt is routinely used to ease lactose intolerance. NCERT Class 12 Biology, Ch. 10 'Microbes in Human Welfare' covers Lactobacillus converting milk sugar to lactic acid in curd.
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