## 3 Applications of Cold Atmospheric Pressure Plasma
### Food Industry and Agriculture  
Global food demand is significantly increasing due to the rapidly growing world population, changes in diet, limited agricultural land, climate change and increasing water deficiency [22]. Agriculture and the food industry face intense pressure because modern-day consumers desire nutritious, fresh, safe and minimally processed foods and drinks. Nowadays, a plethora of methods is available for food processing, such as pasteurization, high-pressure processing, distillation, ozonation, irradiation (ultraviolet light treatment, pulsed light treatment), ultrasonication and chemical treatments (e.g., chlorine, hydrogen peroxide, peroxyacetic acid, organic acid) [25; 61; 90]. However, these kinds of treatments could have a negative impact on the food quality, toxicology, sensorial and nutritive characteristics which make them less attractive to customers [25; 91]. For these reasons, the food industry is continuously seeking alternative methods to improve food production [11; 92]. Inactivation of microorganisms (disinfection of foods, packaging materials and equipment) improves food safety, which is one of the major challenges of this industrial sector (Figure 3) [22]. The major components of food matrices are protein, lipids, carbohydrates, water, minerals and vitamins [10]. The aim of any processing is to impart edibility, palatability and prolong shelf life, while maintaining food quality. CAPP treatment seems to be an effective technology that achieves food preservation at ambient or sublethal temperatures, which reduces the negative thermal effects on the nutritional and quality properties of food. Cold plasma has great potential to inactivate bacteria, viruses, mycotoxins, yeast, molds, endotoxins, etc., on plant- and animal-based foods (e.g., fresh and dry fruits, vegetables, juices, nuts, egg shells, egg-based products, undercooked meat and fish, dairy products, spices, cereals) [20; 23; 52; 90; 91; 93; 94; 95; 96]. Different types of _Escherichia coli_, _Listeria_, _Salmonella_, _Tulane_ virus and hepatitis A virus are the most prevalent foodborne pathogens, which can cause serious health issues [97; 98; 99; 61]. Several pathogens can also survive freezing (_E. coli_ for >180 days) [10]. The specific mechanism of microbial inactivation is still under investigation. The inactivation occurs due to various physicochemical processes (emission of UV radiation, generation of ozone and other active species) [25]. The production of reactive species depends on the used working gas. Reactive oxygen and/or nitrogen species have a potent microbicidal effect, they can damage macromolecules by oxidizing nucleic acids, proteins and lipids [24; 25; 93]. Besides that, the UV radiation can destroy the membranes of microorganisms, structural cell functions and genetic material of pathogens [93]. However, it is worth mentioning that the contribution of UV radiation to the antimicrobial effect is controversial [100]. The resistance to UV light seems to be dependent on the type of microorganism (microbial growth phase, stress conditions, e.g., pH, osmotic concentration and growth temperature) and the plasma device [25]. The most often used reactor configurations are DBD and APPJ. The physicochemical properties (color, texture, pH, acidity, antioxidant activity, amount of proteins, enzymes, carbohydrates, vitamins, lipids, allergens, toxins) could change depending on the plasma treatment process parameters [10; 20; 22]. Furthermore, the operating cost of plasma processing is an important  
Figure 3: Schematic illustration of selected applications of CAPP treatment in medicine, agriculture and food industry. consideration. It mainly depends on the cost of the working gas (plasma generated from noble gases is much more expensive than air) [23]. The antimicrobial effect of the plasma treatment is also highly dependent on the surface structure and surface to volume ratio of the product [23; 25; 57]. CAPP treatment on solid/dry foods mainly affects only their surface.