THE disinfectants (first among the groups in which biocides are divided) comprise a vast group of substances which have the purpose of destroying, eliminating, diminishing, preventing the action of bacteria, viruses, spores and, in some cases, algae or other microorganisms. For these characteristics they are used for the disinfection of environments, surfaces and objects of various kinds, and used in the medical-surgical and industrial sectors, in food production and in breeding (for the disinfection of stables and means of transport for animals).

Maintaining proper hygienic conditions helps to avoid the spread of bacteria and other microorganisms (often referred to with the generic term of germs).

Cleaners are distinguished from disinfectants because they are designed to remove dirt (cleanse). The use of commercially available detergents is generally sufficient to ensure acceptable hygiene conditions in homes, as is the use of soaps and hot water on the skin. In any case, it is always necessary to carefully follow the instructions on the labels of the products used for cleaning.

It often happens that the advertising of many household detergents highlights their antibacterial and disinfectant properties, but in reality the EU regulation on biocidal products (n.528 / 2012) of the European Parliament and of the Council excludes from the definition of disinfectants all detergents (liquid and powder detergents) without a real disinfectant activity.

Only in particular and specific situations (such as the presence of sick people at home) it is advisable to use disinfectants for domestic use, not so much to create a sterile environment (i.e. totally free of germs) but to interrupt any contamination chains (i.e. the possibility that the presence of a contaminated object leads through its use to the contamination of many others). The importance of personal and environmental hygiene has been repeatedly reiterated during the period of new coronavirus health emergency with the constant recommendation to wash hands frequently and disinfect surfaces.

Disinfection, as well as with products biocides with a disinfectant action, it can be performed with ultraviolet radiation or with physical means such as heat (hot air, steam or boiling water).

There are several types of products included in the group of disinfectants:

  • product type 1: human hygiene
    Products used for human hygiene for the purpose of disinfecting the skin or scalp
  • product type 2: disinfectants and algaecides not intended for direct application on humans or animals
    Substances intended for the disinfection of surfaces, materials, equipment and furniture not used in direct contact with food intended for human or animal consumption; in the medical-surgical field they are particularly important, being used in surgical rooms (both for the disinfection of surfaces and for instrumentation), in hospitals and, more generally, in non-hospital care places (assisted health residences for the elderly, home, outpatient care) to prevent and combat infections in hospitals and those relating to health and social care. The products included in this group are also used in: swimming pools, aquariums, air conditioning systems, walls and floors in private, public, professional and industrial.They are also used for the disinfection of air, water not used for human and animal consumption, chemical toilets, waste water, hospital waste and soil. Furthermore, they can be incorporated into fabrics, masks, or paints to obtain treated articles with disinfectant properties
  • product type 3: veterinary hygiene
    Disinfectants, soaps and products for veterinary hygiene with antimicrobial function, also used to disinfect materials and surfaces used for the shelter or transport of animals
  • product type 4: human and animal nutrition sector
    Products used to disinfect equipment, containers, household tools, surfaces or pipes used for: the production, transport, storage or consumption of food or feed (including drinking water) intended for human or animal use; they are also used to impregnate materials that can come into contact with food products
  • product type 5: drinking water
    Products used for the disinfection of drinking water for human and animal consumption. It is important to underline that disinfection and purification are two very different procedures

The choice of substances to use depends on what needs to be disinfected and the type of disinfection to be obtained. A surgical instrument, the surface of a grocery counter, or a small superficial wound will need products with activity levels biocide several that allow, one absolute disinfection, o sterilization, as in the case of surgery (elimination of all pathogenic and non-pathogenic microorganisms) or a relative disinfection with destruction of most, but not necessarily all, of the microorganisms present (reduction of the microbial load).

Main types of disinfectants

The main types of disinfectants are:

  • ethyl alcohol, a very common disinfectant due to its easy availability on the market and its low cost. On the market it is found in concentrations ranging between 60 and 75%. It is used both for the disinfection of surfaces and instruments (except for those in the operating room), and to disinfect the skin without wounds (or intact or intact skin as indicated on the label), for example before making an injection. Alternatively, propyl alcohol can also be used
  • sodium hypochlorite, available on the market in concentrations ranging between 1.5 and 15%, it has an efficient disinfectant action against bacteria, viruses, molds and spores even at low concentrations. It is also commonly known as bleach or bleach (3-5%), euclorine, amuchina (1.5%). At concentrations between 5 and 10%, it can be irritating to skin and eyes (as indicated on the label), while at concentrations above 10% it must be considered a corrosive agent: it is therefore necessary to use it with particular care. L "hypochlorite in the presence of acids develops chlorine which is a toxic gas; in contact with ammonia it generates chloramine which is irritating; in contact with hydrogen peroxide it develops oxygen (non-toxic) which cancels its disinfectant action. For these reasons, sodium hypochlorite must not be mixed with other products to avoid undesirable effects on the health of operators.
  • hydrogen peroxide, it acts with a mechanism similar to that of hypochlorite on bacteria, spores, viruses and yeasts, but is less efficient. It is widely available on the market diluted at different concentrations (from 3 to 12%). In its diluted form it is mainly used to disinfect small wounds, in the home, in professional environments and in cosmetics (also as a whitener and bleaching agent).It degrades easily (the degradation is visible from the swelling of the container) and must be kept in a cool place; when it is concentrated at 35% it must be stored at a temperature of 4 ° C and used with care because it is corrosive
  • quaternary ammonium compounds (QUATs), devoid of a specific color and odor, they are widely used for the disinfection of surfaces and environments (for example in canteens and food preparation areas). They are available on the market in concentrations of 1.5-2.5%; when they are more concentrated they must be diluted in water before use and handled with care because they are irritating and, in some cases, even corrosive to skin and eyes. They are able to eliminate bacteria, most viruses, but generally not spores
  • ethylene oxide, due to its high efficacy against bacteria, fungi, viruses and spores, it is used above all to sterilize surgical instruments, operating rooms and containers for drugs and / or food: the destruction of microorganisms is total. At room temperature it is a gas and as it is flammable and toxic, it can only be handled by trained personnel

Disinfect a wound

In the case of small superficial wounds, which can be disinfected without resorting to the intervention of a doctor, it is important to remember that disinfectants such as alcohol should not be used (to be used only to disinfect intact skin, for example before an injection) . Instead, an antiseptic disinfectant must be used which, once applied to the skin, can limit the development of potentially dangerous microorganisms. Disinfection is necessary because wounds compromise the function of the skin to act as a protective barrier, capable of preventing the entry of microorganisms capable of causing infections (pathogens).

The first operation to do, before acting on a wound, is to wash your hands well (or wear disposable gloves) and cleanse the wound, even simply with running water, to clean it of any residues (for example earth) or bodies strangers such as fabric fibers, wood chips, dust. To disinfect it, antiseptic products for damaged skin, such as hydrogen peroxide or other substances with these characteristics (containing iodine or chlorhexidine) available on the market, must be used. It is possible to rinse the wound by applying these products directly or with the help of sterile gauze. It is not advisable to use cotton wool (or cotton wool) because small fibers could remain inside the wound.Once disinfected, depending on its size and position, it may be decided to cover the wound, at least in the early stages of healing. with sterile gauze or a patch to reduce the risk of microbial contamination.

Useful tips

To allow a disinfectant solution to perform its action, it is important to carry out the disinfection with a thorough cleaning with detergents.

In addition to always following the instructions on the label, it is recommended to wear personal protective equipment (PPE), such as gloves, when indicated for handling disinfectants.

Do not mix different products, thinking of increasing the disinfectant capacity: not only is this not true, but nazi the two products can inactivate. Furthermore, the mixing can release inhalable substances which can cause serious poisoning. This also applies to detergents. For example, the simultaneous or rapid use of ammonia and bleach leads to the formation of chloramines, compounds with an acrid odor which, due to their irritating properties, immediately cause cough, shortness of breath, and irritation to the eyes and throat.Prolonged exposure can cause more severe respiratory tract disorders including pneumonia.

It is always advisable to ensure adequate air exchange during and after the disinfection of the premises, to limit exposure to volatile (and therefore inhalable) substances.

Never refill the disinfectant containers (including hydroalcoholic hand gel): the products have an expiry date after opening (indicated on the label) and the refilling operation does not allow you to have a precise idea of ​​when the product could lose its effectiveness.

Never transfer disinfectant products into unlabeled containers or containers that previously contained liquids or beverages.

Do not leave the disinfectant containers open and, every time they open, do not contaminate the inside of the cap (always put the cap upside down).

Store disinfectants indoors, preferably away from light.

Do not leave detergent or disinfectant products unattended, to prevent children from coming into contact with them and in any case always make sure that they are equipped with a safety lock for children.


Encyclopedia Treccani. Disinfection

Regulation (EU) n. 528/2012 of the European Parliament and of the Council relating to the making available on the market and use of biocides

European Chemicals Agency (ECHA). Information on biocides (English)

Ministry of Health. Biocides and medical-surgical aids

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