The lactic acid bacteria (LAB) improves nutritional quality of curd by increasing the content of -

Vitamin B₁₂

The correct answer is Option (3) → Vitamin B₁₂

In the process of preparing milk products, a starter inoculum containing millions of Lactic Acid Bacteria (LAB), such as Lactobacillus, is added to skimmed or cream milk at temperatures around 40⁰C or below. These LAB convert the lactose sugar in milk into lactic acid, causing the coagulation of milk protein casein and transforming the milk into curd. Beyond this curdling process, LAB enhance the nutritional quality of curd by increasing the presence of vitamin B₁₂.

Moreover, the LAB present in curd play a vital role in inhibiting the growth of disease-causing microbes in the stomach and other parts of the alimentary canal. The beneficial functions of LAB extend beyond curdling milk, encompassing nutritional enhancement and protective measures against harmful microorganisms.