agents that can denature microbial proteins
The selection of an appropriate technique is important, since many physical and chemical agents can cause damage to the cells and tissues of the individual as well as the microbe. Agents of microbial control either sterilize or disinfect. Excess heat energy can cause proteins to become denatured, meaning that they lose their normal three-dimensional shape. Effective temperature for the reduction of microbes is measured as the thermal death point (TDP) of each organism, which is the temperature at which all growth stops. Heavy metals, such as mercury, silver, and copper, denature proteins. Mercury compounds (mercurochrome, metaphen, merthiolate) are only bacteriostatic and are not effective against endospores. Silver nitrate (1%) is sometimes put in the eyes of newborns to prevent gonococcal ophthalmia. Aldehydes, such as formaldehyde and glutaraldehyde, denature microbial proteins. Formalin (37% aqueous solution of formaldehyde gas) is extremely active and kills most forms of microbial life. It is used in embalming, preserving biological specimens, and in preparing vaccines. These agents kill most bacteria, most fungi, and some viruses, but are usually ineffective against endospores. Chloroxylenol (4-chloro-3,5-dimethylphenol) is a broad spectrum antimicrobial chemical compound used to control bacteria, algae, fungi and virus and is often used in antimicrobial soaps and antiseptics. Preservatives, such as sugars, salt, nitrates, nitrites, sulfate, and sulfites inhibit microbial growth in food, usually by producing osmotic environments which are unfavorable to microbial growth. These can be further subdivided as high-, intermediate, or low level agents. Chlorine gas reacts with water to form hypochlorite ions, which in turn denature microbial enzymes. Chlorine is used in the chlorination of drinking water, swimming pools, and sewage. Sodium hypochlorite is the active agent in household bleach. Methods used to control the growth of microbial growth can be placed into two broad categories, physical and chemical. Physical methods either exclude microbes, or reduce their numbers in a solution, or on the surface of a fomite (any nonliving material which might come into contact with the individual) . Iodine also denatures microbial proteins. Iodine tincture contains a 2% solution of iodine and sodium iodide in 70% alcohol. Aqueous iodine solutions containing 2% iodine and 2.4% sodium iodide are commonly used as a topical antiseptic. There are four large categories for agents of chemical control. Antibiotics are produced by microorganisms to kill or inhibit the growth of other microbes. These agents are generally selectively toxic, and can be naturally produced, synthesized, or or semisynthetic.
Formaldehyde, glutaraldehyde and Iodine.