List three ways of disposing infectious microorganisms

1. Disinfection can be done using chemicals. For example, a common practice in a microbiology laboratory is to wipe off the lab bench with alcohol both before and after a work session. Other liquid chemicals that are used as disinfectants include formaldehyde and chlorine-containing compounds (that are commonly referred to as bleach). Chemical disinfection can be achieved using a gas. The most common example is the use of ethylene oxide. Gas disinfection is advantageous when the sample is such that scrubbing of inner surfaces cannot be done, such as in tubing.
2. A second means of waste treatment is sterilization. This is the complete elimination of living organisms. A very common means of sterilization is the use of steam. The most common form of steam sterilization in laboratory settings is the autoclave. For example, in disinfection procedures and other laboratory procedures, items such as the adsorbent material used to wipe the bench and plastic gloves are usually put into a special biohazard bag. The bag is sealed when it is full and is sterilized, typically in an autoclave. The seal is typically an indicator tape that displays marking if the sterilization conditions have been achieved. The inclusion in the load being autoclaved of a solution containing spores of Bacillus sterothermophilus is typically done at regular intervals. Attempts to grow the contents of the solution after autoclaving should be unsuccessful if the sterilization procedure worked. After successful sterilization, the bag can be treated as normal waste.
An autoclave is essentially a large pressure cooker. Samples to be treated are placed in a chamber and a door can be tightly sealed. The seal is so tight that air cannot escape. Steam is introduced into the chamber at high pressure. At higher pressure a higher temperature can be achieved than the 100° C [212° F] possible at atmospheric pressure.
The relationship between time and temperature determines the speed of sterilization. The higher the temperature the more quickly a sample can be sterilized. Typical combinations of temperature and pressure are 115° C [239° F]–10 pounds per square inch (psi), 121° C [249.8° F]–15 psi, and 132° C [269.6° F]–27psi. Which combination is used depends on the material being sterilized. For example, a large and bulky load, or a large volume of culture should be kept in longer. Shorter sterilizations times are sufficient for contaminated objects such /as surgical dressing, instruments, and empty glassware.
3. The third method of treatment of microorganisms and material contaminated with microorganisms is incineration. On a small scale incineration is practiced routinely in a microbiology laboratory to sterilize the metal loops used to transfer microorganisms from one place to another. Exposing the metal loop to a gas flame will burn up and vaporize any living microbes that are on the loop, ensuring that infectious organisms are not inadvertently transferred elsewhere. The method of incineration is also well suited to the treatment of large volumes of contaminated fluids or solids. Incineration is carried out in specially designed furnaces that achieve high temperatures and are constructed to be airtight. The use of a flame source such as a fireplace is unsuitable. The incineration needs to occur very quickly and should not leave any residual material. The process needs to be smoke-free, otherwise microbes that are still living could be wafted away in the rising smoke and hot air to cause infection elsewhere. Another factor in proper incineration is the rate at which sample is added to the flame. Too much sample can result in an incomplete burn.

---

Titany answered the question on September 13, 2021 at 07:30