How are microbes useful in household products ?

We use microbes or products derived from them everyday. A common example is the production of curd from milk.

- Microorganisms such as Lactobacillus and others commonly called lactic acid bacteria ($LAB$).

Lactic acid bacteria grew in milk and convert it to curd. During growth the $LAB$ produce acids that coagulate and partially digest the milk proteins.

A small amount of curd added to the fresh milk as inoculum or starter contains millions of $LAB.$

Which at suitable temperatures multiply, thus converting milk into curd which also improves its nutritional quality by increasing vitamin $\mathrm{B}_{12}$.

In our stomach too, the $LAB$ play very beneficial role in checking disease causing microbes.

The dough which is used for making foods such as Dosa and Idli is also fermented by bacteria. The puffed up appearance of dough is due to the production of $\mathrm{CO}_{2}$ gas.

- Similarly the dough which is used for making bread, is fermented using baker's yeast.

* A number of traditional drinks and foods are also made by fermentation by the microbes. 'Toddy' a traditional drink of some parts of southern India is made by fermenting sap from palms.

- Microbes are also used to ferment fish, soyabean and bamboo shoots to make foods.

Cheese is one of the oldest food items in which microbes were used. Different varieties of cheese are known by their characteristic texture, flavour and taste, the specificity coming from the microbes used.

For example, the large holes in 'Swiss cheese' are due to production of a large amount of $\mathrm{CO}_{2}$ by a bacterium named propionibacterium sharmanii.

The Roquefort cheese are ripened by growing a specific fungi on them, which gives them a particular flavour.

More Information:

Silase is a food for animals. It is made by fermenting carbohydrates present in plant tissues.

Pickles is a result of fermentation process of Lactic Acid of sour fruits and vegetables.

- Striptococus Lacti and Leuconostick citrivotumer are used to make Butter. The specific flavour of butter is due to presence of Diacetyl in it which is produced by striptococus.

Yogurt is made from milk with help of streptococus thermokills and Lactobacillus Bulgarix.