A Biocidal Substance… What Exactly Is It?

                In our previous blog post we brought up the subject of criteria that should be met by an effective biocide. Back then, we mentioned, among other things, the definition of biocidal action, explained what are good-quality raw materials, what should the labels contain, plus we also wrote which active substances are capable of destroying microorganisms. This time we would like to focus on the latter. Which chemical compounds guarantee a disinfecting action? What’s the optimum concentration of a disinfectant? How do individual substances deal with bacteria, viruses, fungi or endospores? If you want to know the answers for these questions – keep on reading!

Alcohols

Alcohols are a group of organic compounds and one of the derivatives of hydrocarbons. They are one of the most popular (but not the only!) type of disinfectants. They own their popularity to the broad spectrum of biocidal action, which affects the vegetative forms of bacteria and fungi as well as enveloped viruses (which include, among others, SARS-CoV-2). The action of these substances is mainly based on the denaturation process (destruction of secondary and tertiary structures) of proteins that, in case of alcohols, also requires the presence of water. Hence, absolute alcohol (anhydrous alcohol) isn’t used in disinfectants, but rather its aqueous solutions. The most effective ones have a concentration in the range between 60% and 90%[1], which is in line with the recommendations of, among others, Polish Chief Sanitary Inspectorate and U.S. Food and Drug Administration that recommend to use preparations with at least 60%[2]^,[3].

The most popular alcohols that you can find either separately or combined in a disinfectant are ethanol and isopropanol (propan-2-ol).

Ethanol

Ethyl alcohol with 60% to 80% abv is not only a perfect bactericide, which denaturates proteins in the bacterial cells, but also a virucide, because it successfully inactivates enveloped viruses by destroying their lipid envelope[4]. Generally, this substance shouldn’t be used if its alcohol concentration is higher than the one mentioned above, because it makes the product evaporate too fast, reducing effectiveness. Additionally, ethanol with abv above 80% works too rapidly on proteins, reducing its disinfecting action.

Izopropanol (propan-2-ol)

Isopropyl alcohol has similar efficiency, evaporation rate and mechanism of biocidal action just as its predecessor. This type of alcohol also features lower effectiveness of dehydrating living tissues in comparison to ethanol, and therefore it is eagerly used in the production of skin disinfectants[5].

Chlorine and chlorine compounds

Preparations that contain chlorine compounds (especially hypochlorites), even at low concentrations, are effective against some of the bacteria, viruses and fungi[6]. This kind of preparations are used to disinfect plumbing installations, fabrics and various types of surfaces – however, it should be kept in mind that they destructively affect rubber and corrode metals, so, in this respect, they are less universal than alcohols. It’s important to point out that some chlorine compounds (although irritating in general) can be safely used on the skin without causing irritation. These include, for example, alkyl dimethyl benzyl ammonium chloride – ingredient of many disinfectant soaps – or the so-called super oxidized water – electrolyzed mixture of water and sodium chloride (table salt), which, in the opinion of many scientists, is capable to not only effectively disinfect the skin’s surface but also help to heal slow-healing wounds[7].

Hydrogen peroxide

Hydrogen peroxide (commonly called oxygenated water – although from the point of view of chemistry only its 3% solution can be called that) is not a well-known disinfectant. But nothing could be farther from the truth! It not only has a wide range of application but also, in comparison to other biocidal substances like, for example, ethanol, its range of action can be considered as the broadest. Research has shown that a higher solution (from 10% to 30%)[8]. of this chemical compound is able to destroy bacteria, mycobacteria, fungi, viruses (both enveloped and non-enveloped ones) and even endospores (dormant form of bacteria). The mechanism of the hydrogen peroxide’s biocidal action involves its decomposition into free hydroxyl radicals that destroy the DNA, membrane lipids and other parts of the microbial cell[9]. The effectiveness of hydrogen peroxide as a disinfectant is supported by the fact that it is used to disinfect medical equipment, fabrics, soft contact lenses[10], and it’s even used in the food industry – as a fruit decay inhibitor[11]. 

Even though this substance evaporates slower than alcohols from the skin’s surface, it isn’t as irritating and it is non-flammable, which is very important when it comes to the storage of disinfectants.

In times when the number of new biocides keeps on increasing on the market, we want our customers to be aware what are they really purchasing and explain to them the mechanisms of action of these products. That is why we decided to share with you a brief characteristic of the most popular active substances used in disinfectants, hoping that this information will help you understand how these preparations work – and, therefore, making you a more conscious buyer.

If you’re interested in high-quality biocidal and cleaning products from a Polish manufacturer, or if you simply want to restock your personal protective equipment kit with face masks and gloves, then take a look at our broad and attractive offer!

[1] http://www.ses.edu.pl/rola-alkoholi-jako-srodkow-dezynfekcyjnych-w-srodowisku-szpitalnym & http://sterylizacja.org.pl/pliki/publikacje/WYTYCZNE_CDC_1.pdf — p. 51 [date of access: 28.05.2020]

[2] https://gis.gov.pl/aktualnosci/jak-skutecznie-dezynfekowac-rece/ [date of access: 28.05.2020]

[3] https://www.fda.gov/drugs/information-drug-class/qa-consumers-hand-sanitizers-and-covid-19 [date of access: 28.05.2020]

[4] http://sterylizacja.org.pl/pliki/publikacje/WYTYCZNE_CDC_1.pdf — p. 51 [date of access: 28.05.2020]

[5] https://journal.com.ph/lifestyle/health-and-wellness/ethyl-or-isopropyl-alcohol [date of access: 28.05.2020]

[6] https://www.lekarski.umed.wroc.pl/sites/default/files/mikrobiologia/files/Dezynfekcja_i_sterylizacja.pdf — p. 2 [date of access: 28.05.2020]

[7] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4972067/ [date of access: 28.05.2020]

[8] https://pbc.gda.pl/Content/5777/zeglinski_jacek_062257.pdf — p. 11 [date of access: 28.05.2020]

[9] http://sterylizacja.org.pl/pliki/publikacje/WYTYCZNE_CDC_1.pdf — p. 63 [date of access: 28.05.2020]

[10] http://sterylizacja.org.pl/pliki/publikacje/WYTYCZNE_CDC_1.pdf — p. 65 [date of access: 28.05.2020]

[11] https://pbc.gda.pl/Content/5777/zeglinski_jacek_062257.pdf — p. 14 [date of access: 28.05.2020]