Correct Option
Statement 1 is correct. Probiotics are defined as live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. These beneficial microorganisms commonly include various species of bacteria (e.g., Lactobacillus, Bifidobacterium) and certain yeasts (e.g., Saccharomyces boulardii).
Statement 3 is correct. Specific probiotic strains, particularly those from the Lactobacillus genus (e.g., Lactobacillus acidophilus), are known to produce the enzyme lactase. Lactase breaks down lactose, which is the primary sugar found in milk, into simpler sugars (glucose and galactose). This enzymatic activity aids in the digestion of milk sugars, which can be particularly beneficial for individuals with lactose intolerance.
Incorrect Options
Statement 2 is incorrect. Many of the beneficial microorganisms commonly used in probiotic products, such as various species of Lactobacillus and Bifidobacterium, are not only found in fermented foods but also naturally constitute a significant and essential part of the human gut microbiota. They are integral to the healthy functioning of the gastrointestinal tract, contradicting the assertion that they do not naturally occur in our gut.
Option (a) is incorrect because statement 3 is also correct, in addition to statement 1.
Option (b) is incorrect because statement 2 is false, while statement 1 is correct.
Option (d) is incorrect because statement 2 is false.