Microorganisms-Friends and Foe Notes

• Some of the microorganisms cause diseases in human beings, plants and animals. Such disease-causing microorganisms are called Pathogen.
• The diseases which are caused due to entry of a pathogen into a living system are known as infectious diseases.
• These pathogens can enter the body via different means.

Means of Spread:

Air:

• Microorganisms spoil our food. Spoiled food emits bad smell and has a bad taste and changed color. The common methods to preserve food

Chemical Method:

• Salts and edible oils are the common chemicals generally used to check the growth of microorganisms.
• Therefore they are called preservatives.
• Sodium Benzoate and Sodium Metabisulphite are common preservatives.

Preservation by Sugar:

• Sugar reduces the moisture content which inhibits the growth of bacteria which spoil food.