Filtration can also be used to remove microbes from liquid samples using
membrane filtration . Membrane filters for liquids function similarly to HEPA filters for air. Typically, membrane filters that are used to remove bacteria have an effective pore size of 0.2 µm, smaller than the average size of a bacterium (1 µm), but filters with smaller pore sizes are available for more specific needs. Membrane filtration is useful for removing bacteria from various types of heat-sensitive solutions used in the laboratory, such as antibiotic solutions and vitamin solutions. Large volumes of culture media may also be filter sterilized rather than autoclaved to protect heat-sensitive components. Often when filtering small volumes,
syringe filter s are used, but
vacuum filter s are typically used for filtering larger volumes (
[link] ).
Would membrane filtration with a 0.2-µm filter likely remove viruses from a solution? Explain.
Name at least two common uses of HEPA filtration in clinical or laboratory settings.
[link] and
[link] summarize the physical methods of control discussed in this section.
Key concepts and summary
Heat is a widely used and highly effective method for controlling microbial growth.
Dry-heat sterilization protocols are used commonly in aseptic techniques in the laboratory. However,
moist-heat sterilization is typically the more effective protocol because it penetrates cells better than dry heat does.
Pasteurization is used to kill pathogens and reduce the number of microbes that cause food spoilage.
High-temperature, short-time pasteurization is commonly used to pasteurize milk that will be refrigerated;
ultra-high temperature pasteurization can be used to pasteurize milk for long-term storage without refrigeration.
Refrigeration slows microbial growth; freezing stops growth, killing some organisms. Laboratory and medical specimens may be frozen on dry ice or at ultra-low temperatures for storage and transport.
High-pressure processing can be used to kill microbes in food. Hyperbaric oxygen therapy to increase oxygen saturation has also been used to treat certain infections.
Desiccation has long been used to preserve foods and is accelerated through the addition of salt or sugar, which decrease water activity in foods.
Lyophilization combines cold exposure and desiccation for the long-term storage of foods and laboratory materials, but microbes remain and can be rehydrated.
Ionizing radiation , including gamma irradiation, is an effective way to sterilize heat-sensitive and packaged materials.
Nonionizing radiation , like ultraviolet light, is unable to penetrate surfaces but is useful for surface sterilization.
HEPA filtration is commonly used in hospital ventilation systems and biological safety cabinets in laboratories to prevent transmission of airborne microbes.
Membrane filtration is commonly used to remove bacteria from heat-sensitive solutions.
Fill in the blank
In an autoclave, the application of pressure to ________ is increased to allow the steam to achieve temperatures above the boiling point of water.
Bacteria doesn't produce energy they are dependent upon their substrate in case of lack of nutrients they are able to make spores which helps them to sustain in harsh environments
_Adnan
But not all bacteria make spores, l mean Eukaryotic cells have Mitochondria which acts as powerhouse for them, since bacteria don't have it, what is the substitution for it?
Assimilatory nitrate reduction is a process that occurs in some microorganisms, such as bacteria and archaea, in which nitrate (NO3-) is reduced to nitrite (NO2-), and then further reduced to ammonia (NH3).
Elkana
This process is called assimilatory nitrate reduction because the nitrogen that is produced is incorporated in the cells of microorganisms where it can be used in the synthesis of amino acids and other nitrogen products
There are nothing like emergency disease but there are some common medical emergency which can occur simultaneously like Bleeding,heart attack,Breathing difficulties,severe pain heart stock.Hope you will get my point .Have a nice day ❣️
_Adnan
define infection ,prevention and control
Innocent
I think infection prevention and control is the avoidance of all things we do that gives out break of infections and promotion of health practices that promote life