The State of Research on Antimicrobial Activity of Cold Plasma

Application of cold plasma therapy for managing subclinical mastitis in cows induced by Streptococcus agalactiae, Streptococcus uberis and Escherichia coli

The primary objective of this study was to assess the effectiveness of cold plasma therapy in managing subclinical mastitis in cows caused by Streptococcus agalactiae, Streptococcus uberis and Escherichia coli. After detection of mastitis pathogens, 38 cows were selected for cold plasma therapy for five days. On the fifth day of treatment, the mastitis agents were re-examined and no causative agents were identified. An additional evaluation conducted 28 days later confirmed the absence of mastitis. Cow productivity, milk composition and quality indicators were assessed at the beginning of the experiment and 32 days from the start (28 days after treatment cessation). After the mastitis treatment, the somatic cell count decreased significantly by between 2.89 and 7.09 times, and the milk yield of the cows at the end of the experiment increased from 0.63 kg per day to 2.82 kg per day (P < 0.01). These results highlight the potential of this innovative approach for managing a prevalent disease that causes substantial losses in the dairy industry. Furthermore, they lay the groundwork for expanded research involving larger sample sizes.

Extraction of polyphenols and essential oils from herbs with green extraction methods - An insightful review

The demand for polyphenols and essential oils (EOs) on the food market is high and grows every year. Its partially the result of the fact that these compounds can be used in formulation of clean label foods, a fast growing food sector. A significant share of polyphenols and EOs are extracted from herbs. The quality of the extracts is determined mainly by the extraction method. Conventional extraction techniques of phytochemicals are time-consuming, operate at high temperatures, and require usage of organic solvents and energy in large quantities. According to the United Nations Sustainability Development Plan, chemical processes should be replaced by green alternatives that would reduce the use of solvents and energy. Ultrasound-Assisted Extraction (UAE), Microwave-Assisted Extraction (MAE) and Cold Plasma-Assisted Extraction (CPAE) meets these criteria. The review shows that each of these techniques seems to be a great alternative for conventional extraction methods ensuring higher yields of bioactive compounds.

Cold Atmospheric Pressure Plasma Solutions for Sustainable Food Packaging

Increasing the number of resistant bacteria resistant to treatment is one of the leading causes of death worldwide. These bacteria are created in wounds and injuries and can be transferred through hospital equipment. Various attempts have been made to treat these bacteria in recent years, such as using different drugs and new sterilization methods. However, some bacteria resist drugs, and other traditional methods cannot destroy them. In the meantime, various studies have shown that cold atmospheric plasma can kill these bacteria through different mechanisms, making cold plasma a promising tool to deactivate bacteria. This new technology can be effectively used in the food industry because it has the potential to inactivate microorganisms such as spores and microbial toxins and increase the wettability and printability of polymers to pack fresh and dried food. It can also increase the shelf life of food without leaving any residue or chemical effluent. This paper investigates cold plasma's potential, advantages, and disadvantages in the food industry and sterilization.

Nonthermal plasma air disinfection for the inactivation of airborne microorganisms in an experimental chamber and indoor air

AIMS

Airborne transmission of diseases presents a serious threat to human health, so effective air disinfection technology to eliminate microorganisms in indoor air is very important. This study evaluated the effectiveness of a non-thermal plasma (NTP) air disinfector in both laboratory experiments and real environments.

METHODS AND RESULTS

An experimental chamber was artificially polluted with a bioaerosol containing bacteria or viruses. Additionally, classroom environments with and without people present were used in field tests. Airborne microbial and particle concentrations were quantified. A 3.0 log10 reduction in the initial load was achieved when a virus-containing aerosol was disinfected for 60 min and a bacteria-containing aerosol was disinfected for 90 min. In the field test, when no people were present in the room, NTP disinfection decreased the airborne microbial and particle concentrations (P < 0.05). When people were present in the room, their constant activity continuously contaminated the indoor air, but all airborne indicators decreased (P < 0.05) except for planktonic bacteria (P = 0.094).

CONCLUSIONS

NTP effectively inactivated microorganisms and particles in indoor air.

Ammonia Retention in Biowaste via Low-Temperature-Plasma-Synthesized Nitrogen Oxyacids: Toward Sustainable Upcycling of Animal Waste

Sustainable fertilizer production is a pressing challenge due to a growing human population. The manufacture of synthetic nitrogen fertilizer involves intensive emissions of greenhouse gases. The synthetic nitrogen that ends up in biowaste such as animal waste perturbs the nitrogen cycle through significant nitrogen losses in the form of ammonia volatilization, a major human health and environmental hazard. Low-temperature air-plasma treatment of animal waste holds promise for sustainable fertilizer production on farmlands by enabling nitrogen fixation via ionization, forming nitrogen oxyacids. Although the formation of nitrogen oxyacids in plasma treatment of water is well-established, the extent of nitrogen oxyanion enrichment in animal waste and its downstream effects on acidifying the waste remain elusive because many compounds found in complex biowaste media may interfere with absorbed NOx species. This work aims to establish that plasma treatment of dairy manure can suppress ammonia loss by volatilization via acidification of animal waste while enriching the waste in total nitrogen due to nitrogen retained in ammonia as well as adding nitrogen oxyacids by reacting NOx with the aqueous slurry. To this end, air-plasma effluent containing NOx is bubbled through dairy manure, which is then analyzed for changes in the nitrogen oxyanion content and pH. Increasing the plasma treatment time results in more acidic manure, reduced ammonium content in the downstream acid trap, and increased nitrogen oxyanion content, where the yield of nitrogen oxyanion from absorbed NOx species is approximately 100%. Increased plasma treatment also led to an increase in the total Kjeldahl nitrogen and the total nitrogen. These results indicate that plasma treatment of animal waste can significantly suppress ammonia pollution from animal husbandry facilities such as dairy farms while upcycling animal waste as a rich organic source of nitrogen.

Investigating the effect of cold atmospheric plasma treatment on the microbial load of raw potato slices

Background and Objectives

Potatoes (Solanum tuberosum), as starchy plants, have been highly esteemed for their rich supply of nutrients. Numerous studies have investigated the potential health benefits of potatoes and explored potential solutions. Among these considerations, the discussion regarding microbial contaminants has remained an important topic.

Materials and Methods

The present study used cold atmospheric plasma (CAP) to evaluate the microbial quality (including mesophilic and psychrotrophic bacteria and mold and yeasts) of raw potato slices during a 14-day storage period. To achieve this goal, the duration of CAP exposure was set at 5, 10, and 15 min, utilizing an electric voltage of 60 kV and a specific frequency of 20 kHz.

Results

The findings revealed the effectiveness of CAP pre-treatment in inhibiting microbial growth over the 14 days when compared to the control sample (untreated sample), with a statistically significant difference (P < 0.05). Moreover, with an extension of the CAP exposure duration to 15 min, there was a significant reduction in the logarithmic count of mesophilic, psychrotrophic microorganisms, molds, and yeasts (4.95, 2.85, and 2.22CFU/g, respectively) in comparison to the control groups (7.5, 5.62, and 5.5CFU/g) on days 0, 7, and 14 of the storage periods (P < 0.05).

Conclusion

The results of this study highlight the potential of CAP pre-treatment on reducing the microbial load in raw potato slices prior to frying, which could potentially influence the overall quality of potato-based products.

Effect of multiple nonthermal plasma treatments of filamentous fungi on cellular phenotypic changes and phytopathogenicity

The effect of multiple sublethal doses of non-thermal plasma treatments on fungal cells phenotypical changes and the reduction in phytopathogenicity of Fusarium oxysporum, Botrytis cinerea, and Alternaria alternata was examined. The intensity of these changes depended on the species of fungus and the number of exposures of the mycelia to the DBD plasma. Microscopic observations showed that the plasma damaged the surface of the hyphae, increased their thickness and decreased overall dry biomass of the organisms. A decrease in pectinolytic activity was found in F. oxysporum and A. alternata, in contrast to B. cinerea, where an increase in pectinolytic activity was observed after the fifth plasma treatment. Changes in specific xylanase activity varied and were dependent on the species of fungus. The percentage of cucumber seeds germinated artificially infected with mycelium after multiple plasma treatments increased compared to those that were mycelium infected prior to plasma exposure. Plants that developed from seeds after plasma exposure were characterized by a higher biomass and longer roots and stems. Multiple treatments of the studied fungi with plasma, followed by seed infection, increased the SWVI and SWVI indexes of cucumber seedlings, but they did not reach the characteristic value of the control seeds (not infected with fungi). The reduced phytopathogenicity of the tested fungi was confirmed by artificial infestation of tomato fruits.

Cold atmospheric plasma induces the curing mechanism of diabetic wounds by regulating the oxidative stress mediators iNOS and NO, the pyroptotic mediators NLRP-3, Caspase-1 and IL-1β and the angiogenesis mediators VEGF and Ang-1

It has been demonstrated that cold atmospheric plasma (CAP) accelerates the wound healing process, however the underlying molecular pathways behind this effect remain unclear. Thus, the goal of the proposed investigation is to elucidate the therapeutic advantages of CAP on angiogenesis, pyroptotic, oxidative stress, and inflammatory mediators during the wound-healing mechanisms associated with diabetes. Intraperitoneal administration of streptozotocin (STZ, 60 mg/Kg) of body weight was used to induce type-1 diabetes. Seventy-five male mice were randomized into 3 groups: the control non-diabetic group, the diabetic group that was not treated, and the diabetic group that was treated with CAP. The key mediators of pyroptosis and its impact on the slow healing process of diabetic wounds were examined using histological investigations employing H&E staining, immunohistochemistry, ELISA, and Western blotting analysis. Angiogenesis proteins (VEGF, Ang-1, and HO-1) showed a significant decline in expression concentrations in the diabetic wounds, indicating that diabetic animals' wounds were less likely to heal. Furthermore, compared to the controls, the major mediators of pyroptosis (NLRP-3, IL-1β, and caspase-1), oxidative stress (iNOS and NO), and inflammation (TNF-α and IL-6) have higher expression levels in the diabetic wounds. These factors substantially impede the healing mechanism of diabetic wounds. Interestingly, our results disclosed the therapeutic impacts of CAP treatment in the healing process of diabetic wounds via significantly regulating the expression levels of angiogenesis, pyroptosis, oxidative stress and pro-inflammatory mediators. Our findings demonstrated the curative likelihood of CAP and the underlying mechanisms for enhancing the healing process of diabetic wounds.

Cold Atmospheric Pressure Plasma: A Growing Paradigm in Diabetic Wound Healing-Mechanism and Clinical Significance

Diabetes is one of the most significant causes of death all over the world. This illness, due to abnormal blood glucose levels, leads to impaired wound healing and, as a result, foot ulcers. These ulcers cannot heal quickly in diabetic patients and may finally result in amputation. In recent years, different research has been conducted to heal diabetic foot ulcers: one of them is using cold atmospheric pressure plasma. Nowadays, cold atmospheric pressure plasma is highly regarded in medicine because of its positive effects and lack of side effects. These conditions have caused plasma to be considered a promising technology in medicine and especially diabetic wound healing because studies show that it can heal chronic wounds that are resistant to standard treatments. The positive effects of plasma are due to different reactive species, UV radiation, and electromagnetic fields. This work reviews ongoing cold atmospheric pressure plasma improvements in diabetic wound healing. It shows that plasma can be a promising tool in treating chronic wounds, including ones resulting from diabetes.

Sublethal Exposure to Plasma-Activated Water Influences the Morphological Characteristics, Phagocytic Ability, and Virulence of Acanthamoeba castellanii

PURPOSE

This study aimed to examine the ultrastructure, cytotoxicity, phagocytosis, and antioxidant responses of Acanthamoeba castellanii trophozoites exposed to sublethal plasma-activated water.

METHODS

Trophozoites were exposed to a sublethal treatment of PAW and compared to untreated viable trophozoites via adhesion assays on macrophage monolayers, osmo- and thermotolerance tests. Bacterial uptake was assessed in treated cells to evaluate their phagocytic characteristics. Oxidative stress biomarkers and antioxidant activities were compared in treated and untreated trophozoites. Finally, the expression of the mannose-binding protein (MBP), cysteine protease 3 (CP3), and serine endopeptidase (SEP) genes was determined in cells.

RESULTS

In PAW-treated trophozoites, cytopathic effects were more extensive and resulted in the detachment of macrophage monolayers. Treated trophozoites could not grow at high temperatures (43 °C). Moreover, they showed osmotolerance to 0.5 M D-mannitol but not to 1 M. Results demonstrated a higher bacterial uptake rate by PAW-treated trophozoites than untreated cells. Activities of superoxide dismutase and catalase and catalase were significantly greater in the treated trophozoites, and the glutathione and glutathione/glutathione disulfide were significantly lower in the PAW-treated cells. Exposure to PAW also significantly increased the malondialdehyde level and total antioxidant capacity. Treatment with PAW led to significantly higher expression of virulent genes like MBP, CP3, and SEP.

CONCLUSION

PAW is a double-edged sword against A. castellanii. PAW is an effective antiamoebic agent in proper usage, whereas its sublethal exposure may reduce its effectiveness and increase amoebas' pathogenicity. An agent's adequate concentration and exposure time are essential to achieve optimum results.

Exploring the potential of cold plasma therapy in treating bacterial infections in veterinary medicine: opportunities and challenges

Cold plasma therapy is a novel approach that has shown significant promise in treating bacterial infections in veterinary medicine. Cold plasma possesses the potential to eliminate various bacteria, including those that are resistant to antibiotics, which renders it a desirable substitute for traditional antibiotics. Furthermore, it can enhance the immune system and facilitate the process of wound healing. However, there are some challenges associated with the use of cold plasma in veterinary medicine, such as achieving consistent and uniform exposure to the affected area, determining optimal treatment conditions, and evaluating the long-term impact on animal health. This paper explores the potential of cold plasma therapy in veterinary medicine for managing bacterial diseases, including respiratory infections, skin infections, and wound infections such as Clostridium botulinum, Clostridium perfringens, Bacillus cereus, and Bacillus subtilis. It also shows the opportunities and challenges associated with its use. In conclusion, the paper highlights the promising potential of utilizing cold plasma in veterinary medicine. However, to gain a comprehensive understanding of its benefits and limitations, further research is required. Future studies should concentrate on refining treatment protocols and assessing the long-term effects of cold plasma therapy on bacterial infections and the overall health of animals.

Plasma activated Ezhangfeng Cuji as innovative antifungal agent and its inactivation mechanism

Candida albicans is a highly drug-resistant fungus for which new treatments are urgently needed due to the lack of clinically effective options. In this study, we evaluated the antifungal activity and mechanism of plasma-activated Ezhangfeng Cuji (PAEC) against Candida albicans and compared it with physiological saline (PS), plasma-activated physiological saline (PAPS) and Ezhangfeng Cuji (EC). After dielectric barrier discharge (DBD) plasma treatment with EC for 20 min followed by a 10 min immersion of Candida albicans, the fungus was reduced by approximately 3 orders of magnitude. High performance liquid chromatography (HPLC) results showed an increase of 41.18% and 129.88% in the concentration of oxymatrine and rhein, respectively, after plasma-treated EC. The concentrations of reactive species (RS), such as H₂O₂, [Formula: see text], and O₃, were found to be higher and the pH value was getting lower in PS after plasma treatment. Detailed analysis of intracellular material leakage, reactive oxygen species (ROS), apoptosis for Candida albicans and observation by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) demonstrated that PAPS, EC and PAEC disrupt the morphological structure of Candida albicans to varying degrees.Additionally, specific analyses on Candida albicans virulence factors, such as adhesion to tissue surfaces, cell surface hydrophobicity (CSH), the transition of yeast-phase cells to mycelium-phase cells, and the secretion of hydrolytic enzymes for Candida albicans were conducted and found to be inhibited after PAPS/EC/PAEC treatment. In our investigation, the inhibitory effects on Candida albicans were ranked from strong to weak as follows: PAEC, EC, PAPS, and PS.

Efficient deactivation of aerosolized pathogens using a dielectric barrier discharge based cold-plasma detergent in environment device for good indoor air quality

Air pollution is one of the top 5 risks causing chronic diseases according to WHO and airborne transmitted pathogens infection is a huge challenge in the current era. Long living pathogens and small size aerosols are not effectively dealt with by the available indoor air purifiers. In this work, a dielectric barrier discharge (DBD) based portable cold-plasma detergent in environment device is reported and its disinfection efficiency has been analyzed in the indoor environment of sizes up to 3 × 2.4 × 2.4 m³. The deactivation efficiency of total microbial counts (TMCs) and total fungal counts (TFCs) is found to be more than 99% in 90 min of continuous operation of the device at the optimized parameters. The complete inactivation of MS2 phage and Escherichia coli bacteria with more than 5 log reduction (99.999%) has also been achieved in 30 min and 90 min of operation of the device in an enclosed environment. The device is able to produce negative ions predominantly dominated by natural plasma detergent along with positive ions in the environment similar to mother nature. The device comprises a coaxial DBD geometry plasma source with a specially designed wire mesh electrode of mild steel with a thickness of 1 mm. The need for feed gas, pellets and/or differential pressure has been eliminated from the DBD discharge source for efficient air purification. The existence of negative ions for more than 25 s on average is the key advantage, which can also deactivate long living pathogens and small size aerosols.

The Role of Cold Atmospheric Plasma in Wound Healing Processes in Critically Ill Patients

Critically ill patients are at risk of skin wounds, which reduce their quality of life, complicate their pharmacological regimens, and prolong their hospital stays in intensive care units (ICUs), while also increasing overall mortality and morbidity rates. Cold atmospheric plasma (CAP) has been proposed as a viable option for many biological and medical applications, given its capacity to reduce wound bacterial contamination and promote wound healing. The aim of this narrative review is to describe how CAP works and its operating mechanisms, as well as reporting its possible applications in critical care settings. The success of CAP in the treatment of wounds, in particular, bedsores or pressure sores, presents an innovative path in the prevention of nosocomial infections and an opportunity of reducing the negative implications of these diseases for the NHS. This narrative review of the literature was conducted following the 'Scale for the Assessment of Narrative Review Articles' (SANRA) methodology. Previous literature highlights three biological effects of plasma: inactivation of a wide range of microorganisms, including those that are multi-drug-resistant; increased cell proliferation and angiogenesis with a shorter period of plasma treatment; and apoptosis stimulation with a longer and more intensive treatment. CAP is effective in many areas of the medical field, with no significant adverse effects on healthy cells. However, its use can produce potentially serious side effects and should, therefore, be used under expert supervision and in appropriate doses.

Inactivation of antibiotic-resistant bacteria and antibiotic-resistance genes in wastewater streams: Current challenges and future perspectives

The discovery of antibiotics, which was once regarded as a timely medical intervention now leaves a bitter aftertaste: antimicrobial resistance (AMR), due to the unregulated use of these compounds and the poor management receiving wastewaters before discharge into pristine environments or the recycling of such treated waters. Wastewater treatment plants (WWTPs) have been regarded a central sink for the mostly unmetabolized or partially metabolised antibiotics and is also pivotal to the incidence of antibiotic resistance bacteria (ARBs) and their resistance genes (ARGs), which consistently contribute to the global disease burden and deteriorating prophylaxis. In this regard, we highlighted WWTP-antibiotics consumption-ARBs-ARGs nexus, which might be critical to understanding the epidemiology of AMR and also guide the precise prevention and remediation of such occurrences. We also discovered the unsophistication of conventional WWTPs and treatment techniques for adequate treatment of antibiotics, ARBs and ARGs, due to their lack of compliance with environmental sustainability, then ultimately assessed the prospects of cold atmospheric plasma (CAP). Herein, we observed that CAP technologies not only has the capability to disinfect wastewater polluted with copious amounts of chemicals and biologicals, but also have a potential to augment bioelectricity generation, when integrated into bio electrochemical modules, which future WWTPs should be retrofitted to accommodate. Therefore, further research should be conducted to unveil more of the unknowns, which only a snippet has been highlighted in this study.

Comparison of the Effect of Cold Plasma with Conventional Preservation Methods on Red Wine Quality Using Chemometrics Analysis

In this study, the effect of cold plasma (CP) on the physicochemical and biological properties of red wine was investigated in comparison with the effects of the conventional preservation method and the combined method. In addition, the effect of storage time after the application of each of the analyzed methods was evaluated. The study examined the effects of the different preservation methods on the pH, color, phenolic content, antioxidant activity and microbiological purity of the red wine. Chemometric analysis was used to discover the relationship between the preservation method used and wine quality. In the wine samples tested, a reduction in phenolic compounds and a decrease in antioxidant activity were noted after storage. This effect was mildest for preservation methods with the addition of potassium metabisulphite and those in which a mixture of helium and nitrogen was used as the working gas. On a positive note, the CP treatment did not affect the color of the wine in a way perceptible to the consumer: ∆E*—1.12 (He/N₂; 5 min). In addition, the lowest growth of microorganisms was detected in the CP-treated samples. This indicates the potential of cold plasma as an alternative method to the use of potassium metabisulfite in wine production, which may contribute to its wider use in the alcohol industry in the future.

Efficacy of Cold Atmospheric Plasma Therapy on Chronic Wounds: An Updated Systematic Review and Meta-Analysis of RCTs

Objective

A previous meta-analysis has revealed that cold atmospheric plasma (CAP) might not be clinically beneficial to chronic wounds. However, several new randomized controlled trials (RCTs) reported that CAP was an effective treatment option for accelerating wound healing in chronic wounds. The purpose of this review is to incorporate these new results and evaluate the efficacy of CAP in chronic wounds.

Methods

The major databases, including PubMed, Embase, Cochrane Library, and Web of Science, were searched for articles related to CAP treatment in chronic wounds until March 21, 2022. The literature retrieval and evaluation were carried out by two independent researchers.

Result

A total of 13 randomized clinical trials published between 2010 and 2022 were finally included. CAP therapy showed to be more effective in reducing the area of wounds (mean difference (MD): -1.74, 95%; confidence interval (CI): [-3.14, -0.33], p = 0.02), compared with non-CAP treatments. The immediate reduction of the bacterial load was higher in the CAP group than in the control group. (MD: -0.37, 95%; CI: [-0.7, -0.05], p = 0.02).

Conclusion

No significant changes were found in long-term antibacterial efficacy and pain perception between the two groups. However, more RCTs of excellent methodological quality are required to confirm technical details of the source of AP and the appropriate duration of the treatment with plasma.

Study of the synergistic effect of singlet oxygen with other plasma-generated ROS in fungi inactivation during water disinfection

Cold atmospheric plasma (CAP) possesses the ability of high-efficiency disinfection. It is reported that mixtures of reactive oxygen species (ROS) including ^·OH, ¹O₂, O₂^- and H₂O₂ generated from CAP have better antimicrobial ability than mimicked solution of mixture of single ROS type, but the reason is not clear. In this study, CAP was applied to treat yeasts in water in order to investigate the fungal inactivation efficiency and mechanism. The results showed that plasma treatment for 5 min could result in >2-log reduction of yeast cells, and application of varied ROS scavengers could significantly increase the yeast survival rate, indicating that ^·OH and ¹O₂ played the pivotal role in yeast inactivation. Moreover, the synergistic effect of ¹O₂ with other plasma-generated ROS was revealed. ¹O₂ could diffuse into cells and induce the depolarization of mitochondrial membrane potential (MMP), and different levels of MMP depolarization determined different cell death modes. Mild damage of mitochondria during short-term plasma treatment could lead to apoptosis. For long-term plasma treatment, the cell membrane could be severely damaged by the plasma-generated ^·OH, so a large amount of ¹O₂ could induce more depolarization of MMP, leading to increase of intracellular O₂^- and Fe²⁺ which subsequently caused cell inactivation. ¹O₂ could also induce protein aggregation and increase of RIP1/RIP3 necrosome, leading to necroptosis. With participation of ¹O₂, endogenous ^·OH could also be generated via Fenton and Haber-Weiss reactions during plasma treatment, which potentiated necroptosis. Adding l-His could mitigate membrane damage, inhibit the drop of MMP and the formation of necrosome, and thus prevent the happening of necroptosis. These findings may deepen the understanding of plasma sterilization mechanisms and provide guidance for microbial killing in the environment.

Nivalenol Mycotoxin Concerns in Foods: An Overview on Occurrence, Impact on Human and Animal Health and Its Detection and Management Strategies

Mycotoxins are secondary metabolites produced by fungi that infect a wide range of foods worldwide. Nivalenol (NIV), a type B trichothecene produced by numerous Fusarium species, has the ability to infect a variety of foods both in the field and during post-harvest handling and management. NIV is frequently found in cereal and cereal-based goods, and its strong cytotoxicity poses major concerns for both human and animal health. To address these issues, this review briefly overviews the sources, occurrence, chemistry and biosynthesis of NIV. Additionally, a brief overview of several sophisticated detection and management techniques is included, along with the implications of processing and environmental factors on the formation of NIV. This review’s main goal is to offer trustworthy and current information on NIV as a mycotoxin concern in foods, with potential mitigation measures to assure food safety and security.

A Review of Selected Types of Indoor Air Purifiers in Terms of Microbial Air Contamination Reduction

Aims: With the ongoing pandemic and increased interest in measures to improve indoor air quality, various indoor air purifiers have become very popular and are widely used. This review presents the advantages and disadvantages of various types of technologies used in air purifiers in terms of reducing microbial contamination. Methods: A literature search was performed using Web of Science, Scopus, and PubMed, as well as technical organizations dealing with indoor air-quality to identify research articles and documents within our defined scope of interest. Relevant sections: The available literature data focus mainly on the efficiency of devices based on tests conducted in laboratory conditions with test chambers, which does not reflect the real dimensions and conditions observed in residential areas. According to a wide range of articles on the topic, the actual effectiveness of air purifiers is significantly lower in real conditions than the values declared by the manufacturers in their marketing materials as well as technical specifications. Conclusions: According to current findings, using indoor air purifiers should not be the only measure to improve indoor air-quality; however, these can play a supporting role if their application is preceded by an appropriate technical and environmental analysis considering the real conditions of its use.

Applications of Plasma Produced with Electrical Discharges in Gases for Agriculture and Biomedicine

The use of thermal and non-thermal atmospheric pressure plasma to solve problems related to agriculture and biomedicine is the focus of this paper. Plasma in thermal equilibrium is used where heat is required. In agriculture, it is used to treat soil and land contaminated by the products of biomass, plastics, post-hospital and pharmaceutical waste combustion, and also by ecological phenomena that have recently been observed, such as droughts, floods and storms, leading to environmental pollution. In biomedical applications, thermal plasma is used in so-called indirect living tissue treatment. The sources of thermal plasma are arcs, plasma torches and microwave plasma reactors. In turn, atmospheric pressure cold (non-thermal) plasma is applied in agriculture and biomedicine where heat adversely affects technological processes. The thermodynamic imbalance of cold plasma makes it suitable for organic syntheses due its low power requirements and the possibility of conducting chemical reactions in gas at relatively low and close to ambient temperatures. It is also suitable in the treatment of living tissues and sterilisation of medical instruments made of materials that are non-resistant to high temperatures. Non-thermal and non-equilibrium discharges at atmospheric pressure that include dielectric barrier discharges (DBDs) and atmospheric pressure plasma jets (APPJs), as well as gliding arc (GAD), can be the source of cold plasma. This paper presents an overview of agriculture and soil protection problems and biomedical and health protection problems that can be solved with the aid of plasma produced with electrical discharges. In particular, agricultural processes related to water, sewage purification with ozone and with advanced oxidation processes, as well as those related to contaminated soil treatment and pest control, are presented. Among the biomedical applications of cold plasma, its antibacterial activity, wound healing, cancer treatment and dental problems are briefly discussed.

Biochemical and Physiological Plant Processes Affected by Seed Treatment with Non-Thermal Plasma

Among the innovative technologies being elaborated for sustainable agriculture, one of the most rapidly developing fields relies on the positive effects of non-thermal plasma (NTP) treatment on the agronomic performance of plants. A large number of recent publications have indicated that NTP effects are far more persistent and complex than it was supposed before. Knowledge of the molecular basis and the resulting outcomes of seed treatment with NTP is rapidly accumulating and requires to be analyzed and presented in a systematic way. This review focuses on the biochemical and physiological processes in seeds and plants affected by seed treatment with NTP and the resulting impact on plant metabolism, growth, adaptability and productivity. Wide-scale changes evolving at the epigenomic, transcriptomic, proteomic and metabolic levels are triggered by seed irradiation with NTP and contribute to changes in germination, early seedling growth, phytohormone amounts, metabolic and defense enzyme activity, secondary metabolism, photosynthesis, adaptability to biotic and abiotic stress, microbiome composition, and increased plant fitness, productivity and growth on a longer time scale. This review highlights the importance of these novel findings, as well as unresolved issues that remain to be investigated.

The Effects of Plasma-Activated Water Treatment on the Growth of Tartary Buckwheat Sprouts

The aim was to investigate the effects of buckwheat sprout treated with plasma-activated water (PAW) and their quality, nutrients (protein, amino acids, fat, and carbohydrates), functional active ingredients (total flavonoids, total phenolic acids, γ-gamma aminobutyric acid (GABA), and polysaccharides), and antioxidant activity during germination. PAW had no negative effects on the germination rate, but promoted the stem growth instead, which indicated 1.12-fold higher germination rate compared with the control group. The results of sensory evaluation demonstrated that the obtained sprouts were bright green, shinning, crisp and smooth, with sufficient moisture, and easy to chew. During germination (1–9 days), the water content, amino acids, and reducing sugars of sprouts showed an increasing trend and were basically higher in the PAW group than in the control group, while protein, carbohydrate, and crude fat presented a decreasing trend. The results were that the flavonoid, phenolic acid, γ-GABA, polysaccharides content, and antioxidant activity during germination showed a gradual upward trend but with slight differences, and the antioxidant properties of buckwheat sprouts might be related to the phenolic acid and polysaccharides content. These data show that the PAW treatment on buckwheat sprout have great potential as a dietary source of antioxidant function with health benefits.

The impact of cold plasma on the phenolic composition and biogenic amine content of red wine

The effect of cold plasma (CP) on phenolic compound (PC) and biogenic amine (BA) contents of red wine was investigated for the first time. The influence of CP was compared with the effects of a wine preservation using potassium metabisulfite and a combined method. The PC profile was determined by UPLC-PDA-MS/MS while BAs using DLLME-GC-MS. Chemometric analysis also was used. The content of PCs was 3.1% higher in the sample preserved by CP treatment (5 min, helium/nitrogen) compared to a sample preserved by the addition of potassium metabisulfite (100 mg/L). On a positive note, CP treatment reduced the concentration of BAs in the wine samples. The lowest BA contents were recorded after 10 min of cold plasma (helium/oxygen) treatment with the addition of potassium metabisulfite (1120.85 μg/L). The results may promote interest in CP as a potential alternative method for the preservation of wine and other alcoholic beverages.

The Antimicrobial Efficacy Of Plasma Activated Water Against Listeria and E. coli Is Modulated By Reactor Design And Water Composition

AIMS

This study aimed to compare the efficacy of plasma activated water (PAW) generated by two novel plasma reactors against pathogenic foodborne illness organisms.

METHODS AND RESULTS

The antimicrobial efficacy of PAW produced by a bubble spark discharge (BSD) reactor and a dielectric barrier discharge-diffuser (DBDD) reactor operating at atmospheric conditions with air, multiple discharge frequencies and Milli-Q and tap water, was investigated with model organisms Listeria innocua and Escherichia coli in situ. Optimal conditions were subsequently employed for pathogenic bacteria Listeria monocytogenes, E. coli and Salmonella enterica. DBDD-PAW reduced more than 6-log of bacteria within 1 minute. The BSD-PAW, while attaining high log reduction, was less effective. Analysis of physicochemical properties revealed that BSD-PAW had a greater variety of reactive species than DBDD-PAW. Scavenger assays designed to specifically sequester reactive species demonstrated a critical role of superoxide, particularly in DBDD-PAW.

CONCLUSIONS

DBDD-PAW demonstrated rapid antimicrobial activity against pathogenic bacteria, with superoxide the critical reactive species.

SIGNIFICANCE AND IMPACT OF STUDY

This study demonstrates the potential of DBDD-PAW produced using tap water and air as a feasible and cost-effective option for antimicrobial applications, including food safety.

Evaluation of cold atmospheric-pressure plasma against burn wound infections and gene silencing

Background and Objectives

Non-thermal atmospheric-pressure plasma or cold plasma is defined as an ionized gas. This study aimed to investigate the effect of cold plasma on Pseudomonas aeruginosa strains. Also, the expression level of the alp virulence gene before and after treatment with cold plasma was compared with the Housekeeping gene gyrA.

Materials and Methods

P. aeruginosa isolates recovered from hospitalized burn patients at Shahid Motahari Burns Hospital, Tehran, Iran. The Kirby Bauer disk diffusion method was used to determine the antimicrobial susceptibility test. Then, the antibacterial effect of atmospheric non-thermal plasma was evaluated on P. aeruginosa in as in vitro and in vivo studies at different times on Muller Hinton agar and in mouse model (treated by plasma every day/ 90 sec). The histopathological study was evaluated by Hematoxylin-Eosin staining. Data were analyzed using SPSS software by the Chi-square test and Pvalues less than 0.05 considered as statistically significant.

Results

Results indicated that non-thermal atmospheric plasma inhibited the growth of P. aeruginosa. The non-thermal helium plasma accelerates wound healing for 6 days. Results showed that cold plasma decreased virulence gene expression alp after treatment. Therefore, cold plasma can be suggested as a complementary therapeutic protocol to reduce bacterial infection and accelerate wound healing and reduce the expression of virulence genes of pathogens.

Conclusion

Cold plasma showed pathogen inhibitory properties of P. aeruginosa and virulence alkaline protease and wound healing properties in animal models, so this inexpensive and suitable method can be presented to the medical community to disinfect burn wounds and improve wound healing.

Cold Atmospheric Plasma Changes the Amino Acid Composition of Solutions and Influences the Anti-Tumor Effect on Melanoma Cells

Cold Atmospheric Plasma (CAP) is an ionized gas near room temperature. Its anti-tumor effect can be transmitted either by direct treatment or mediated by a plasma-treated solution (PTS), such as treated standard cell culture medium, which contains different amino acids, inorganic salts, vitamins and other substances. Despite extensive research, the active components in PTS and its molecular or cellular mechanisms are not yet fully understood. The purpose of this study was the measurement of the reactive species in PTS and their effect on tumor cells using different plasma modes and treatment durations. The PTS analysis yielded mode- and dose-dependent differences in the production of reactive oxygen and nitrogen species (RONS), and in the decomposition and modification of the amino acids Tyrosine (Tyr) and Tryptophan (Trp). The Trp metabolites Formylkynurenine (FKyn) and Kynurenine (Kyn) were produced in PTS with the 4 kHz (oxygen) mode, inducing apoptosis in Mel Im melanoma cells. Nitrated derivatives of Trp and Tyr were formed in the 8 kHz (nitrogen) mode, elevating the p16 mRNA expression and senescence-associated ß-Galactosidase staining. In conclusion, the plasma mode has a strong impact on the composition of the active components in PTS and affects its anti-tumor mechanism. These findings are of decisive importance for the development of plasma devices and the effectiveness of tumor treatment.

Morphological and physiological changes in Lentilactobacillus hilgardii cells after cold plasma treatment

Atmospheric cold plasma (ACP) inactivation of Lentilactobacillus hilgardii was investigated. Bacteria were exposed to ACP dielectric barrier discharge with helium and oxygen as working gases for 5, 10, and 15 min. The innovative approach in our work for evaluation of bacterial survival was the use in addition to the classical plate culture method also flow cytometry which allowed the cells to be sorted and revealed different physiological states after the plasma treatment. Results showed total inhibition of bacterial growth after 10-min of ACP exposure. However, the analysis of flow cytometry demonstrated the presence of 14.4% of active cells 77.5% of cells in the mid-active state and 8.1% of dead cells after 10 min. In addition, some of the cells in the mid-active state showed the ability to grow again on culture medium, thus confirming the hypothesis of induction of VBNC state in L .hilgardii cells by cold plasma. In turn, atomic force microscopy (AFM) which was used to study morphological changes in L. hilgardii after plasma treatment at particular physiological states (active, mid-active, dead), showed that the surface roughness of the mid-active cell (2.70 ± 0.75 nm) was similar to that of the control sample (2.04 ± 0.55 nm). The lack of considerable changes on the cell surface additionally explains the effective cell resuscitation. To the best of our knowledge, AFM was used for the first time in this work to analyze cells which have been sorted into subpopulations after cold plasma treatment and this is the first work indicating the induction of VBNC state in L. hilgardii cells after exposure to cold plasma.

Foodborne Viruses and Innovative Non-Thermal Food-Processing Technologies

In recent years, several foodborne viruses' outbreaks have been recorded worldwide. Μost of the foodborne viruses have a low infection dose, are stable and can persist and survive in foods for a long time without loss of infectivity. The most important foodborne viruses are: human norovirus (HuNoV), human rotavirus (HRV), hepatitis A virus (HAV), hepatitis E virus (HEV), human astrovirus (HAstV), Aichi virus (AiV), sapovirus (SaV), human adenovirus (HAdV) and enterovirus (EV). In recent years, innovative non-thermal food-processing technologies including high-pressure processing (HPP), cold plasma (CP), ultraviolet light (UV), irradiation and pulsed electric field (PEF) for improving the quality and safety of foods, including foods of animal origin, have been under research. This review presents the recent data on foodborne viruses and reviews the innovative non-thermal technologies for the control of the foodborne viruses in foods.

Cold atmospheric pressure (physical) plasma in dermatology: where are we today?

Cold atmospheric pressure plasma is physical plasma (essentially ionized gas) created at room temperature and atmospheric pressure, and it has complex effects on cells, tissues, and living organisms. These effects are studied extensively for medical and dermatological use. This article reviews current achievements and new trends in clinical dermatological cold plasma research, discusses the basics of plasma physics and plasma engineering, and describes the most important areas of laboratory plasma research to provide a well-rounded understanding of the nature, present applications, and future promise of this exciting, emerging technology.

Supply Systems of Non-Thermal Plasma Reactors. Construction Review with Examples of Applications

A review of the supply systems of non-thermal plasma reactors (NTPR) with dielectric barrier discharge (DBD), atmospheric pressure plasma jets (APPJ) and gliding arc discharge (GAD) was performed. This choice is due to the following reasons: these types of electrical discharges produce non-thermal plasma at atmospheric pressure, the reactor design is well developed and relatively simple, the potential area of application is large, especially in environmental protection processes and biotechnologies currently under development, theses reactors can be powered from similar sources using non-linear transformer magnetic circuits and power electronics systems, and finally, these plasma reactors and their power supply systems, as well as their applications are the subject of research conducted by the author of the review and her team from the Department of Electrical Engineering and Electrotechnology of the Lublin University of Technology, Poland.

A systematic study of the antimicrobial mechanisms of cold atmospheric-pressure plasma for water disinfection

Waterborne diseases caused by pathogenic microorganisms pose a severe threat to human health. Cold atmospheric-pressure plasma (CAP) has recently gained much interest as a promising fast, effective, economical and eco-friendly method for water disinfection. However, the antimicrobial mechanism of CAP in aqueous environments is still not clearly understood. Herein, we investigate the role of several short-lived reactive oxygen species (ROS) and cellular responses in the CAP inactivation of yeast cells in water. The results show that singlet oxygen (¹O₂), hydroxyl radical (OH) and superoxide anion (O₂^-) are generated in this plasma-water system, and O₂^- served as the precursor of OH. The 5-min plasma treatment resulted in the effective inactivation (more than 2-log reduction) of yeast cells in water. The ROS scavengers significantly increased the survival ratio in the following order: water < D-Man (scavenging OH) < SOD (scavenging O₂^-) < L-His (scavenging ¹O₂), indicating that ¹O₂ contributes the most to the yeast inactivation. In addition, the acidic pH had a synergetic antimicrobial effect with ROS against the yeast cells. During the CAP inactivation process, yeast cells underwent apoptosis in the first 3 min due to the accumulation of intracellular ROS, mitochondrial dysfunction and intracellular acidification, later followed by necrosis under longer exposure times, attributed to the destruction of the cell membrane. Additionally, L-His could switch the cell fate from necrosis to apoptosis through mitigating plasma-induced oxidative stress, indicating that the level of oxidative stress is a critical factor for cell death fate determination. These findings provide comprehensive insights into the antimicrobial mechanism of CAP, which can promote the development of CAP as an alternative water disinfection strategy.