Micro-organisms such as Lactobacillus and others commonly called lactic acid bacteria (LAB) grow in milkand convert it to curd. During growth, the LAB produce acids that coagulate and partially digest the milkproteins. A small amount of curd added to the fresh milk as inoculum or starter contain millions of LAB, whichat suitable temperatures multiply, thus converting milk to curd, which also improves its nutritional quality byincreasing vitamin B12. In our stomach too, the LAB play very beneficial role in checking disease causingmicrobes.
(2)CHEESE
Cheese, is one of the oldest food items in which microbes were used. Different varieties of cheese are knownby their characteristic textur flavour and taste, the specificity coming from the microbes used.The large holes in 'Swiss cheese' are due to production of a large amount of CO2 by a bacterium namedPropionibacterium sharmani
OTHER PRODUCT :-
The dough , which is used for making foods such as dosa and idli is also fermented by bacteria. The puffed-upappearance of dough is due to the production of CO2 gas. Similarly the dough, which is used for making bread,is fermented using baker's yeast (Saccharomyces cerevisiae).
A number of traditional drinks (e.g. ''Toddy' prepared from sap of palms) and foods are also made by fermentationby the microbes.
Microbes are also used to ferment fish, soyabean and bamboo shoots to make foods.
MICROBES IN INDUSTRIAL PRODUCTS
1.ALCOHOLIC (Fermanted) BEVERAGE
Microbes especially yeasts have been used from time immemorial for the production of beverages like wine,beer, whisky, brandy or rum. For this purpose the same yeast Saccharomyces cerevisiae used for bread-makingand commonly called brewer’s yeast, is used for fermenting malted cereals and fruit juices, to produce ethanol.Depending on the type of the raw material used for fermentation and the type of processing (withor without distillation) different types of alcoholic drinks are obtained. Wine and beer are produced withoutdistillation whereas whisky, brandy and rum are produced by distillation of the fermented broth.
Some other common products of yeast fermentation are
–[i]Beer – It is produced from Hordeum Vulgare[Barely] malt and alcohol content is 3-6%
[ii]Wine – Produced from grapes, alcohol content is 10-20%.
[iii] Brandy – Produced by distilation of wine and alcohol content is 60-70%
[iv] Gin – Produced from European Rye-Scale cereal, alcohol content is 40%.
[v]Rum – Produced from Molasses of Sugarcane and alcohol contents is 40%
.ANTIBIOTICS
The term was coined by Selman Waksman (1942)Antibiotics produced by microbes are regarded as one of the most significant discoveries of the twentiethcentury and have greatly contributed towards the welfare of the human society. Anti is a Greekword that means ‘against’, and bio means ‘life’, together they mean ‘against life’ (in the contextof disease causing organisms); whereas with reference to human beings, they are ‘pro life’ andnot against. Antibiotics are chemical substances, which are produced by some microbes and can kill or retardthe growth of other (disease-causing) microbes.
You are familiar with the commonly used antibiotic Penicillin. Do you know that Penicillin was the firstantibiotic to be discovered and it was a chance discovery? Alexander Fleming while working on Staphy-lococci bacteria, once observed a mould growing in one of his unwashed culture plates around which Staphy-lococci could not grow. He found out that it was due to a chemical produced by the mould and he named itPenicillin after the mould Penicillium notatum. However, its full potential as an effective antibiotic wasestablished much later by Ernest Chain and Howard Florey.This antibiotic was extensively usedto treat American soldiers wounded in World War II. Fleming, Chain and Florey were awardedthe Nobel Prize in 1945, for this discovery.
After Penicillin, other antibiotics were also purified from other microbes. Antibiotics have greatly improved ourcapacity to treat deadly diseases such as plague, whooping cough (kali khansi ), diphtheria (gal ghotu) andleprosy (kusht rog), which used to kill millions all over the globe. Today, we cannot imagine a world withoutantibiotics
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