Microorganisms and Sterilization Techniques

Study Notes

Microorganisms are everywhere and can cause issues like food spoilage and disease.
Killing or inhibiting their growth is essential.
This aims to destroy pathogens and prevent transmission.
It also reduces or eliminates microorganisms contaminating water, food, and substances.

Sterilization: A process that removes all living microorganisms, including those in vegetative or spore states.
Sterile: Any material that has been sterilized.
Germicide: A chemical agent killing pathogenic microorganisms.
Disinfection: Destroys or removes all pathogenic organisms capable of causing infection. It kills vegetative pathogens but not bacterial endospores.
Sepsis: The growth of microorganisms in the body or the presence of microbial toxins in blood and other tissues.

An excellent way to reduce the microbial population in heat-sensitive solutions using different types of filters.
Filters physically remove contaminants rather than destroying them.
Depth Filters: Made of fibrous or granular materials bonded into a thick layer with twisting channels.
- Candle Filters: Diatomaceous earth (Berkefeld) or unglazed porcelain (Chamberlain). Used for water purification.
- Asbestos Filters: Made from asbestos like magnesium silicate. Seitz and Sterimat are disposable discs.
- Sintered Glass Filters: Made from fused finely powdered glass particles. They are brittle and expensive.
Membrane Filters: Composed of cellulose acetate, cellulose nitrate, polycarbonate, polyvinylidene fluoride, or other synthetic materials. They are circular porous membranes.

Refers to any practice that prevents the entry of infectious agents into sterile tissues, preventing infection.
Antiseptics: Chemicals applied to exposed body surfaces, wounds, and surgical incisions to destroy or inhibit vegetative pathogens.
Sanitization: A cleansing technique mechanically removing microorganisms and food debris to reduce contaminants.
Sanitizers: Compounds like soap or detergents used for sanitization.
Degerming: Reducing the number of microbes on the human skin. Done by scrubbing or immersing in chemicals.

Physical Methods:
- Sunlight
- Heat
- Filtration
- Radiation
- Sound waves
Chemical Methods:
- Specific chemicals used to kill bacteria or limit their growth

A natural method of sterilization for water in tanks, rivers, and lakes.
Direct sunlight has an active germicidal effect that destroys microorganisms in water sources.