Disinfectants

Disinfection should always be preceded by a surface cleaning step. Food contamination remaining on a poorly cleaned surface is a source of nutrition and foci for the growth of microorganisms. Good sanitary and hygienic condition in a food processing plant is achieved by a combined program of thorough cleaning of all surfaces and equipment, followed by disinfection. It is known that thorough cleaning removes up to 90% of microorganisms from the surface. On an unwashed surface, dirt residues not only protect microorganisms from sanitization, but also reduce the effectiveness of the disinfectant due to the dilution effect or chemical reaction of the organic substance with the disinfectant.

Chemical compounds intended for use in the food industry as disinfectants are distinguished by their chemical structure, activity against various types of microorganisms and the conditions under which they exhibit maximum activity. In general, the case is true: the higher the concentration of the disinfectant, the faster and more effective its action. To select an effective disinfectant, it is necessary to experimentally or theoretically determine potential pathogenic microorganisms and make sure that the selected disinfectant is active against these microorganisms. Since chemical disinfectants are not highly penetrating, microorganisms in cracks, scratches and other surface irregularities, inside mineral contaminants, may not be completely destroyed after processing. For the effect of chemical disinfectants to be effective, the surface must be thoroughly cleaned before processing.

Disinfectants are classified according to their effect on various forms of microorganisms: bactericides destroy vegetative microorganisms, sporicides destroy spores, fungicides destroy fungi, virucides destroy viruses. Chemical antiseptics are used to disinfect the skin. Bacteriostatic substances prevent bacteria from multiplying without actually killing them.

Chemical compounds affect the cell in several ways. One of them is protein coagulation. In the normal state, the protein is dispersed within the cell. The disinfectant compound interacts with the protein causing it to coagulate and precipitate. The cell stops functioning normally and dies. Another way of the disinfectant effect on microorganisms is the destruction of the cell membrane. The cell membrane works as a selective barrier, it allows some solutions to enter the cell, while other solutions cannot overcome this barrier. Substances that are sorbed on the cell membrane can markedly change its physicochemical characteristics, interfering with normal functioning. This can lead to inhibition of activity or cell death.

Chemical antagonism. Enzymes perform their catalytic function due to their affinity for certain chemical compounds called natural substrates. Natural substrates are normally found inside the cell. If natural substrates are noticeably replaced with a disinfectant, the enzyme will be bound to the chemical, not the substrate. In the case of the formation of a sufficiently stable bond between the enzyme and the chemical disinfectant, the cell loses its ability to reproduce.

Usually, chemical disinfectants are classified according to the type of biologically active substance that is included in its composition.