## 2 Impurities and Contamination  
### Removal of Mechanical Impurities  
The herbs obtained from the cultivation or from the natural state are submitted to hygiization during the production process. In the first stage, the mineral impurities are removed (mainly the particles of soil), as well as the organic pollutants consisting of fragments of other plants, sticks, dead insects, etc. [11]. Most frequently, the mechanically driven winnowers are used for this purpose, which separate individual fractions on the sieve screens at the same time (grain, lighter grasses, dust, and dust). In addition, different types of separators are used, e.g., the separators intended for sifting loose products with taking into account the size of the particles. They are primarily used in production of mint, hibiscus, chamomile, common valerian, etc. and also in the selection of seasonings. As well, they may be used to separate the parts of plants, e.g., stalks from leaves wet before drying. The other types of machines used for herbal purification are filter cyclones, which trap dust particles [12]. Table 1 shows the types of contamination of herbal raw materials.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multicolumn{2}{c}{**Source of Pollution Origin**} & \multicolumn{4}{c}{**Types of Contamination**} \\ \cline{2-5} \multicolumn{1}{c}{} & \multicolumn{2}{c}{**Physical**} & \multicolumn{2}{c}{**Chemical**} & \multicolumn{2}{c}{**Biological**} \\ \hline Soil & ✓ & Sand, & ✓ & Residues of fertilizers and plant & ✓ & Gram-positive bacteria of the genera _Protas_, \\  & ✓ & Glass, & protection products & _Stripococcus_, _Rhodococcus_, and _Cenobacterium_, as well as \\  & ✓ & Elements of other plants, & & & spore bacteria of the genus _Bacillus_, especially _B. subtilis_, \\  & ✓ & twigs, sticks, & & _B. pumilis_, _B. cerus_, and _B. licheniformis_, and spore-forming \\  & ✓ & Strings, & & anaerhes of the genus _Crystallization_, \\  & ✓ & Metals. & & _C. Actinocytes and molds (including _Penicillium_, _Alternaria_, _Fastrium_, and _Cenosporium_) & \\  & & & & & _Sticks of the genus _Escherichia_, _Pseudomonas_, \\  & & & & & _Amaligenes_, \\  & & & & & _Amaligenes_, \\  & & & & & \(S\) bacteria of the genus _Mycobacterium_, _Agrobacteriumrium_, and _Xanthomonas_ \\ \hline Water & ✓ & Sand, stones & ✓ & Wastewater & &
\begin{tabular}{c} Spoilage bacteria (of the genus _Bacillus_), \\ \end{tabular} \\  & & & ✓ & Fertilizers, & & Molds (e.g., _Maor_, _Penicillium_, and _Cenosporium_), \\  & & & ✓ & Heavy metals & Yeast-like fungi (_Rhodorula_, _Candidia_, _Crypococcus_, and _Dchampions_) \\ \hline Air & ✓ & Exhaust gas, & ✓ & Heavy metals & ✓ & Bacterial spores (e.g., of the genus _Bacillus_ \\  & ✓ & Ashes, & ✓ & Doxins & and _Censtridium_) \\  & ✓ & Dust & ✓ & Sulphur dioxide & ✓ & Mushroom and mildew spores. \\  & ✓ & Nitrogen dioxide & & & \\ \hline Anthropogenic & ✓ & Clothing elements (buttons) & ✓ & Substances added by producers of & ✓ & The bacteria _Salmonella typhimurium_, \\  & ✓ & Jewerly items & herbal products in order to improve & _Listaria monocytogenes_, _Enterococcus faecalis_, \\  & ✓ & Hair. & quality, color, and storage capacity. & _Tersini entrerecolitita_, and _Escherichia coli_. \\ \hline Invalid harvest, storage, & ✓ & Dust, & ✓ & Exhaust gases, & _Straplyococcus aureus_ \\ and processing. & ✓ & Greases from machines & ✓ & Substances that migrate from & \\  & & & & installations, equipment and packaging & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Types of herbal contamination.