How Disinfectants Work

What is a disinfectant?
Disinfectants are the chemical agents that either inhibit microbial activities and growth or are lethal and kill the microorganisms. In man’s struggle to control the microbes responsible for disease and illness many organic and inorganic chemicals have been found to be toxic to microorganisms.

Which microorganisms are we trying to kill?
Disease-producing microorganisms are known as pathogens. Bacteria, fungi, protozoa, as well as viruses are the pathogenic microorganisms we attempt to control. Bacteria are microscopic single cell living organisms. Fungi are more advanced multi-cellular organisms which can be infectious. Mold and mildew are types of fungi which cause deterioration. Protozoa are small unicellular animal microorganisms. Some are parasitic and others can live free of a host. The most common protozoan diseases would include malaria and amebiasis. A virus is a microscopic organism that lacks the capacity to reproduce itself unless it gains entrance into a cell of another living organism. Once within the cell of another organism the virus utilizes the host cell’s protein making abilities to reproduce itself. Disease is the result of the chemical damage done to the host cell by the virus’ use of it. Some of the most well known diseases caused by viruses are the common cold, influenza, hepatitis A and B, measles, mumps, rabies, rubella, herpes simplex I & II, and smallpox

How do disinfectants work?
Disinfectants work by adversely affecting the microbe’s cell by either disrupting its physical makeup or by blocking its energy-yielding or synthetic processes. It is important to remember that disinfectants are consumed or expend their ability to affect the microorganisms during this process.

A brief history of disinfectants
The first disinfectant, carbolic acid, better known today as phenol, was introduced into the operating room by Joesph Lister in the late 19th century. As a result post operative infections were dramatically reduced and the science of disinfectants was born. Man’s desire to end disease has led to the development of many different chemical compounds that kill pathogenic microorganisms.

What are the different chemical compounds used in manufacturing disinfectant products?
Halogens are a family of elements, the most common being fluorine, chlorine, bromine, and iodine. The very reason that these elements make food disinfectants is also their biggest drawback. They attack cells and destroy their structures. They are, however, non-selective and can also be aggressive and corrosive to human skin or other environmental surfaces. Iodofors (iodine-containing compounds) are used primarily for the skin and have undesirable staining properties which make them impracticable for cleaning solutions. Chlorine is the most aggressive and commonly used of the halogens. It is very corrosive and generally associated with bleach. Bromine is not as abundant in nature, making it far more expensive than chlorine and less practical to use. Fluorine is not used because of the extreme toxicity associated with fluoride compounds.
Phenol, originally extracted from coal tar, was known as carbolic acid and is produced synthetically today. In its raw form phenol is a white poisonous corrosive crystal. Phenolics kill pathogenic microorganisms through a chemical reaction which disrupts the proper functioning of the cell wall.

Pine Oil has often been referred to "Nature’s own disinfectant." Pine oils are effective against microorganisms in the same way as phenols, wherein they have a chemical action which disrupts the cell wall. This chemical action is not nearly as strong as that of phenols, so cleaning solutions must contain a considerable amount of pine oil to be effective.
Quaternary Ammonium Compounds (Quats) were first introduced in 1935. Quats do not work by being corrosive or by an aggressive chemical action as do other disinfectants compounds. Quats are effective disinfectants because they are attracted to the protein coating (cell wall) of the microbe and therefore are considered selective in their aggression. There have been four significant advances in the development of quats over the years and today most quaternaries are classified as 1st generation through 4th generation products.
Generally speaking, 1st generation quat products are identified by the chemical compound name n-alkyl dimethyl benzyl ammonium chloride and are often referred to as ADBAC quats. The first significant improvement came in 1955 with the 2nd generation quat compounds and the addition of an ethyl group to the formulation - n-alkyl dimethyl ethyl benzyl ammonium chloride. Also, the original ADBAC quats underwent a modification to the chemical chain improving the tolerance to environmental conditions. Other industries also contributed to the continuing improvements in quaternaries. Nonionic detergents were being developed with far greater cleaning power than natural soaps. Combined with quats, a truly superior detergent-disinfectant was ready to emerge.
Twin chain quats, the most significant advance in quaternary technology, brought the 3rd generation of quats to the field in 1965. Twin chain quat compounds normally contain any combination of the octyl decyl dimethyl; dioctyl dimethyl; or didecyl dimethyl ammonium chloride groups. Seeking ways to reduce the amount of active chemical ingredients and still maintain peak performance, chemists developed the 4th generation of quaternary compounds by combining the twin chain quats with the earlier ADBAC quats. These newest quats remained active under even the most difficult conditions but with almost 50% fewer active chemical ingredients than ADBACs alone. Additionally, they promised lower toxicity, improved convenience, and greater economy.

Will hard water affect the performance of disinfectants?
Hard water has long been considered a major problem facing disinfectants. Whether a phenolic, a quat ,or an iodophor, the metallic ions in hard water bond to disinfectants reducing their biocidal activity. Modern quats, however, are capable of withstanding water of up to 90 grains of hardness.

Why do disinfectants have different kill claims?
Often, questions arise regarding the kill claims of certain quat compounds. Why does one products claim bactericidal activity while other claim fungicide and virucidal as well? To answer this question it is important to remember that the E. P. A. was formed in the early 1970’s and since that time all registrations for disinfectants have fallen under their control. Test protocols were establish for consistent testing and products had to be submitted for testing to prove their kill claims. Since the 4th generation products were more economical and maintained a higher activity under adverse conditions most manufacturers have only submitted these formulas for the more expensive and time consuming testing that allows them to make these higher kill claims.

To establish testing standards, ppms ( parts per million) were used to measure the amount of disinfectant in a solution required to provide efficacy data for kill claims. Figuring the ppms of a particular product is achieved by multiplying the total amount of quaternary in the product by 10,000 and dividing that answer by the recommended dilution.

How do I determine what type of disinfectant to use?
Generally speaking, bleach (Chlorine) kills just about everything due to its highly corrosive nature. It is very harsh on everything it comes in contact with, so where it is used is very important. Chlorine is an excellent oxidizing agent (such as its use in swimming pools) and because of this is very unstable which makes for a very short shelf life. Some products such as our BTB formula container stabilizers to slow down the decay. Chlorinated products should be stored in colored container to reduce their exposure to light which increases the decay rate. REMEMBER TO NEVER MIX BLEACH WITH ANY OTHER COMPOUND, IT IS HIGHLY REACTIVE AND EASILY REACTS TO FORM OTHER COMPOUNDS MOST OR WHICH ARE DANGERIOUS TO YOU!!!!

Phenols are not as corrosive as chlorine, but again they are non-selective and attack all surfaces. Phenolic disinfectants are still the preferred product by some health care institutions as these are also effective against pathogenic, spore-forming bacteria such as tubercle bacillus. Spore-forming bacteria are more difficult to disrupt since they are able to produce a shell (spore), usually associated with it’s dormant stage.

Pine Oil products require such a high amount of oil that you’d better really like the smell of pine. And again their solvent action is non-selective in that it attacks everything. Cost today is again a factor in these products because they must contain a high percentage of pine oil to be effective. In today’s marketplace the cost of pure pine oil is rather steep.

Quats are by far the most popular choice of disinfectants today because of their low cost and selective aggression. They have broad spectrum effectiveness against a range of microorganisms and provide the highest overall value to the customer. Quats are formulated with a variety of detergents for more specific applications. For example, a highly alkaline degreaser disinfectant or a pH neutral disinfectant for damp mopping high gloss floor finish can be made using the same quat compound. Quats are used as sanitizers and deodorants in a number of formulas as well. There may be times when your concern for total kill will outweigh the negative impacts of the product used. Many kennels use bleach to control parvo virus and some health care institutions will demand phenolic cleaners against tuberculosis.

Overall, which type of product you should choose depends on the needs of the particular application. Michco can match those desires with a product to gain the benefits you desire.

 

This information is presented based on our research which we believe to be correct although it may be biases. No guarantee is expressed or implied. Please provide your own evaluation prior to drawing any conclusions. This information is provided by Betco Corporation, Toledo Ohio, and is used with their persission © 1992 by Betco.