s Microbes are small organisms which are not visible to naked eye and can be seen only
under microscope. Microbes are very diverse, as they are present everywhere in soil,
water, air, dust particles, inside and outside our bodies. Microbes can survive in extreme
conditions, snow, thermal vents (temperature of 100°C), highly acidic habitats, etc.
s Microbes belong to diverse group of organisms-bacteria, fungi, protozoa, microscopic
plants. Viruses (nucleoprotein entities), Viroids (only nucleic acids) and Prions
(proteinaceous infectious agents) are also included amongst microbes.
s Microbes are useful in various processes in homes, industries, agriculture and sewage
treatments.
HOUSEHOLD PRODUCTS
s Dairy Products: Lactic acid bacteria (LAB) like Lactobacillus are added to milk. They
convert lactose sugar of milk into lactic acid. Lactic acid causes coagulation and partial
digestion of milk protein casein. Milk is changed into curd, yoghurt and cheese. A small
amount of curd added to the fresh milk as inoculum contains millions of LAB.
Dairy Products
Curd
Prepared by inoculating skimmed and cream
milk with Lactobacillus acidophilus, at a
temperature of about 40°C or less.
Yoghurt
Produced by curdling milk with the help
of Streptococcus thermophilus and
Lactobacillus bulgaricus, at about 45°C for
4 hours.
Butter Milk
Acidulated product, formed by inoculating
skimmed milk with starter culture of
Streptococcus cremoris, Lactobacillus
acidophilus, at 22°C for 18 hours.Sour Cream
Cream obtained by churning of milk is
inoculated with Streptococcus lactis for
producing lactic acid for imparting the
characteristic flavour.
Cheese
For preparing cheese, milk is curdled with the help of lactic acid bacteria. Curd is heated gently to
separate cheese from whey, and liquid left in cheese is allowed to drain by hanging it in cloth.Microbes in Human Welfare
Analysis of various PMTs from 2012-201620122013201420152016AIPMT/NEET21––3AIIMS–13–3AMU1–41-Kerala––212K.CET––213J & K––22–Class XII