Control of Microorganisms BMV201

Study Notes

Microorganisms are the most populous and diverse group of organisms, found everywhere.
They play essential roles in nature, including: • Photosynthesis (fixing atmospheric carbon) • Nitrogen fixation (enriching soil to enable plant growth) • Recycling nutrients back to soil when organisms die
Microorganisms benefit humans in various ways, such as: • Food production (e.g., bread) • Beverage manufacturing (e.g., wine, beer) • Vitamin production (e.g., riboflavin, vitamin B2) • Antibiotic production (e.g., ampicillin)
However, some microorganisms can cause disease in plants, animals, and humans.

John Tyndall showed that dust carries microorganisms, and in the absence of dust, broth remains sterile even when exposed to air.
Ferdinand Cohn discovered that heat-resistant bacteria produce endospores.
Robert Koch: • Established the relationship between Bacillus anthracis and anthrax. • Developed Koch's postulates, criteria to conclusively prove that a disease is caused by a microorganism. • Disproved spontaneous generation, and his criteria are still used today to establish the relationship between a disease and a particular microorganism.

To prevent disease spread, it is necessary to control the growth and abundance of microorganisms.
Fomites (inanimate objects like doorknobs, toys, or towels) can harbor microorganisms and need to be treated to reduce transmission.
The method used to reduce microorganisms on fomites depends on two factors.

Microorganisms are the most populous and diverse group of organisms, found everywhere, and play essential roles in nature.
They:
- Photosynthesize, fixing atmospheric carbon.
- Fix nitrogen, enriching soil for plant growth.
- Recycle nutrients back to soil when organisms die.
They benefit humans by:
- Aiding in food production (e.g., bread).
- Enabling beverage manufacturing (e.g., wine, beer).
- Producing vitamins (e.g., riboflavin, vitamin B2).
- Providing antibiotics (e.g., ampicillin).
Some microorganisms, however, cause disease in plants, animals, and humans.

John Tyndall discovered that dust carries microorganisms.
In the absence of dust, broth remains sterile, even when directly exposed to air.
Ferdinand Cohn showed that heat-resistant bacteria produce endospores.
Robert Koch:
- Established the relationship between Bacillus anthracis and anthrax.
- Developed criteria to prove that disease is caused by a microorganism (germ theory of disease).
- Disproved spontaneous generation.
- Developed Koch's postulates, still used today to establish the relationship between disease and microorganisms.

To prevent disease spread, it is necessary to control microorganism growth and abundance.
Fomites (inanimate objects like doorknobs, toys, or towels) can harbor microorganisms and need to be treated to reduce transmission.
The method used to reduce microorganisms on fomites depends on two factors.