## 3 Review of Methods
### The Physical Methods for the Decontamination of Herbs  
One of the methods for the physical decontamination of herbs is to subject them to high hydrostatic pressure, usually with values from 300 to 1000 MPa. Even under the pressure of 100 MPa, the number of bacteria in the colon rod decreases by 99.9% (_Escherichia coli_). The presence of this microorganism, of which certain strains can cause dangerous poisoning (_Staphylococcus aureus_ and salmonella) is not allowed by hygienic standards in the products intended for consumption [24]. Fungus from the order of the yeast white litter (_Candida albicans_) dies after 5 min, when subjected to hydrostatic pressure of 500 MPa, as well as the yeast _Saccharomyces cerevisiae_. This method is also highly effective against mold, but unfortunately, it reduces significantly the content of essential oils in plants subjected to it. The use of carbon dioxide under high pressure shows relatively low decontamination efficiency. It does not destroy satisfactorily the bacterial and mold spores [20]. In addition, its effectiveness decreases with the decrease in the moisture content in the plant material [25]. The carbon dioxide also causes the loss of significant amount of aromatic oils and causes changes in the chemical composition of herbs. In case of vegetative forms of bacteria and fungi, the method using microwaves, i.e., electromagnetic waves of 0.0001-1 m length, turns out to be useful [20; 26]. However, spores of Gram-positive hay bacillus (_Bacillus subtilis_) and bacteria of the genus _Clostridium_ and mold spores prove to be resistant to their action [27]. In this case, a large loss of the content of aromatic oils and the changes in their chemical composition take place. Exposing the herbal raw materials to short-term high temperatures, usually from 110 to 200 \({}^{\circ}\)C, and, at the same time, to the pressure of about 20 MPa is called extrusion [28]. This technology does not bring about significant organoleptic changes in the herbs, but it significantly affects their consistency, which is especially unfavorable in the production of seasonings. In turn, the ionizing radiation has been recognized as safe by the World Health Organization, but it is not accepted by consumers. While the dose of 10 kGy is taken as the upper tolerated dose, the successful disposing of the viruses and microbial spores sometimes requires a dose of up to five times higher [25; 29]. Then, the negative chemical and visual changes occur in the herbs that are decontaminated by the use of this technology. However, on the other hand, in case of some plant seasonings, the doses of 5-6 kGy are sufficient to ensure that the amount of microorganisms contained in them meets the requirements of the standards. It should be stressed that the radiation decontamination is only exceptionally associated with an increase in temperature, therefore, it is suitable for heat-sensitive raw materials. The use of infrared radiation has an effect only on the surface of plants, therefore, in this case, it is difficult to talk about a significant reduction in microorganisms. The steam is used for many herbal raw materials, but more often it is used in the production of seasonings. The steam temperature is usually between 100 and 200 \({}^{\circ}\)C. Then, the plant material is dried with hot air and subjected to rapid cooling. As a result, the significant reduction in microorganisms takes place, primarily, bacilli of the Enterobacteriaceae family, some granulomas, spores of the hay bacillus bacterium, bacteria of the genus _Clostridium_, as well as yeast and mold [15]. At the same time, however, there is a very significant change in the color of plants containing chlorophyll and carotenoid dyes, and also, the significant material depletion of numerous biologically active compounds [14; 29]. This technology is also not suitable for the decontamination of powdered raw materials, because they get lumpy under the influence of water vapor. A typical device for decontamination with the use of the steam method is a sterilizer.