• Microbes, also known as micro-organisms (like protozoa, bacteria, fungi, plant viruses, viroids and prisons) can be observed under microscopes. Microbe is a minute life form which have a size of less than 0.1 mm.
• Microbes are present everywhere - in soil, water, air, inside our bodies and that of other animals and plants. They are present even at sites where no other life form could possibly exist-sites, deep in the soil, under the layers of snow several meters thick and in highly acidic environment.
• Microbes can be grown on culture nutritive media to form colonies which are used for mass production of certain desirable products and for scientifi c study of metabolism, genetics and structure of micro-organism.
• During their metabolism, microbes produces chemicals, some of which have been in use by human beings since ages. Microbes can be modifi ed genetically to produce many type of chemicals. Therefore, microbes are ideal for biotechnology.
MICROBES IN HOUSEHOLD PRODUCTS
• Humans share a close relationship with a surprising variety of microscopic organism.
Microbes play an important role in the preparation of household products & industrial products valuable to human beings.
Microbes in food prepossessing products
• LAB is lactic acid bacteria which produce acids that coagulates and partially digest the milk proteins. Milk is changed into curd, yoghurt & cheese etc.
• A small amount of curd act as inoculum in fresh milk. Inoculum actually contains millions of lactic acid bacteria.
• Lactic acid bacteria causes coagulation of milk protein casein. They also improve the nutritional quality of curd by increasing vitamin B12.
Examples –
• Lactobacillus lacti : Milk fermentation.
• Lactobacillus acidophilus : Cheese production.
• Streptococcus thermophilus or Lactobacillus bulgaricus : Yoghurt production.
• Saccharomyces cerevisiae : Bread production.
• S. lactis, L. bulgaricus : Kefi r production.
• Lactose fermenting yeast : Butter milk production.
• In stomach, LAB plays an important role in checking disease causing microbes.
Curd
• Curd is prepared from both skimmed and cream milk by inoculating the same with LAB. Milk is boiled and cooled to temperature of slightly less than 40°C. It is mixed with a small quantity of inoculum or curd. The latter contains Lactobacillus acidophilus.
• Curd also possesses antimutagenic and anticancer biochemicals. The bacterium produces Lactase which converts milk sugar lactose into lactic acid. Yogurt
• Yogurt is a preserved milk product having a distinct taste and a thick texture than milk. Milk is heated to 80° – 90°C for half an hour. It is cooled to 40° – 43°C and mixed with inoculum containing Streptococcus thermophilus and Lactobacillus burlgaricus. After four hours yoghurt is ready.
