Test: Microbes in Household Products (NCERT) - NEET MCQ

Microbes are omnipresent, which means they are found everywhere. They can be found in soil, water, air, ice, inside bodies of human beings, animals, and plants, and even in thermal vents.

Prions are highly resistant glycoprotein particles which function as infectious agents. Prions can also act as catalyst converting normal protein into prion state. Prions are not affected by proteases, nucleases, temperature upto 800^oC, UV radiations and formaldehyde.

Microbes such as. Lactobacillus and others commonly called lactic acid bacteria (LAB) grow in milk and convert it into curd. During growth, such bacteria produce adds (mainly lactic add) that coagulate and partially digest the milk proteins. A small amount of curd, known as starter, is added to the milk and kept at a suitable temperature, where lactic acid bacteria multiply in millions and converts milk into curd that also improves its nutritional quality by increasing vitamin B₁₂. It also checks the growth of disease-causing microbes in the stomach.

Yoghut (yogurt) is produced by curdling milk with the help of Streptococcus thermophillus and Lactobacillus bulgaricus. The temperature is maintained at about 45^∘C(40^∘−60^∘C) for four hours. It has a flavour of lactic acid and acetaldehyde.

Cheese is one of the oldest milk products prepared with the help of microbes.The curd is separated from liquid part or whey to form cheese. Dosa, Upma are fermented preparation of rice and black gram. The two are allowed to ferment for 3-12 hours with air borne Leuconostoc and Streptococcus species of bacteria. Toddy is a traditional drink of some parts of South India which is made by fermentation of sap of palms.