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Abdoli B, Khoshtaghaza MH, Ghomi H, Torshizi MAK, Mehdizadeh SA, Pishkar G, Dunn IC. Cold atmospheric pressure air plasma jet disinfection of table eggs: Inactivation of Salmonella enterica, cuticle integrity and egg quality. Int J Food Microbiol 2024; 410:110474. [PMID: 37984215 DOI: 10.1016/j.ijfoodmicro.2023.110474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 10/26/2023] [Accepted: 11/01/2023] [Indexed: 11/22/2023]
Abstract
Eggshell cuticles are first lines of defense against egg-associated pathogens, such as Salmonella enterica serovar Enteritidis (SE). Infections from eggs contaminated with this strain remain a significant risk. In addition, changes in the cuticle are closely related to changes in egg safety. The emerging non-thermal atmospheric pressure plasma technology enables a high rate of microbial inactivation at near-ambient temperatures, making it ideal for food safety applications. This study examines the effects of a cold atmospheric pressure air plasma jet (CAAP-J) on eggshell cuticle and egg quality whilst inactivating SE. Shell eggs inoculated with SE (7 log10 cfu/egg) were used as the samples to test the decontamination performance of the device. The tests were conducted using an industrial CAAP-J with different power levels (600-800 W), exposure times (60-120 s), at a fixeddistance of 20 mm from the plasma jet and an air flow rate of 3600 L/h. It was found that the best results were obtained after 120 s at maximum plasma power (800 W). Subsequent to the implementation of this plasma procedure, it was determined that no viable cells could be detected. After CAAP-J treatment, the temperature remains below 50.5 °C, thereby minimizing the risk of altering egg quality. All specific measurements (egg white pH, yolk pH, yolk color, HU, and eggshell breaking strength) have shown that CAAP-J treatment has no negative effect on egg quality. No changes in eggshell cuticle quality after CAAP-J treatment was confirmed through scanning electron microscope (SEM).
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Affiliation(s)
- Bahareh Abdoli
- Department of Biosystems Engineering, Tarbiat Modares University, Tehran, Iran
| | | | - Hamid Ghomi
- Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, Iran
| | | | - Saman Abdanan Mehdizadeh
- Mechanics of Biosystems Engineering Department, Faculty of Agricultural Engineering and Rural Development, Agricultural Sciences and Natural Resources University of Khuzestan, Ahvaz, Iran
| | | | - Ian C Dunn
- The Roslin Institute, The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian EH25 9RG, Scotland, United Kingdom
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Zhang H, Zhang C, Han Q. Mechanisms of bacterial inhibition and tolerance around cold atmospheric plasma. Appl Microbiol Biotechnol 2023:10.1007/s00253-023-12618-w. [PMID: 37421472 PMCID: PMC10390405 DOI: 10.1007/s00253-023-12618-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 05/29/2023] [Accepted: 06/01/2023] [Indexed: 07/10/2023]
Abstract
The grim situation of bacterial infection has undoubtedly become a major threat to human health. In the context of frequent use of antibiotics, a new bactericidal method is urgently needed to fight against drug-resistant bacteria caused by non-standard use of antibiotics. Cold atmospheric plasma (CAP) is composed of a variety of bactericidal species, which has excellent bactericidal effect on microbes. However, the mechanism of interaction between CAP and bacteria is not completely clear. In this paper, we summarize the mechanisms of bacterial killing by CAP in a systematic manner, discuss the responses of bacteria to CAP treatment that are considered to be related to tolerance and their underlying mechanisms, review the recent advances in bactericidal applications of CAP finally. This review indicates that CAP inhibition and tolerance of survival bacteria are a set of closely related mechanisms and suggests that there might be other mechanisms of tolerance to survival bacteria that had not been discovered yet. In conclusion, this review shows that CAP has complex and diverse bactericidal mechanisms, and has excellent bactericidal effect on bacteria at appropriate doses. KEY POINTS: • The bactericidal mechanism of CAP is complex and diverse. • There are few resistant bacteria but tolerant bacteria during CAP treatment. • There is excellent germicidal effect when CAP in combination with other disinfectants.
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Affiliation(s)
- Hao Zhang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Disease, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, People's Republic of China
| | - Chengxi Zhang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Disease, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, People's Republic of China
| | - Qi Han
- Department of Oral Pathology, State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, People's Republic of China.
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Kumagai H, Sugaya T, Tominaga T. Cauterization of Narrow Root Canals Untouched by Instruments by High-Frequency Current. MATERIALS (BASEL, SWITZERLAND) 2023; 16:2542. [PMID: 37048836 PMCID: PMC10095201 DOI: 10.3390/ma16072542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/06/2023] [Accepted: 03/21/2023] [Indexed: 06/19/2023]
Abstract
The mechanical removal of bacteria is fundamental to the treatment of infected root canals, but complete sterilization of biofilms tends not to extend to uninstrumented areas. However, during electrical conduction to a root canal filled with a conductor, the higher impedance where the root canal is narrower generates Joule heat that may result in a large temperature increase and sterilization. The effect of a high-frequency electric current on the wall of a simulated narrow root canal was investigated by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). Simulated root canals, 0.1 mm in diameter, were prepared in dentine blocks. The root canal wall was treated with Plank-Rychlo solution for 5 min to create a decalcified layer. The simulated root canal was filled with either saline or NaClO, and 150 or 225 V at 520 kHz was applied for 0 s, 1 s, or 5 s. As the conduction time increased, and when the saline was replaced with NaClO, the proportion with a flat decalcified surface decreased, dentinal tubules and a lava-like morphology were significantly more evident on SEM (p < 0.01), and EDS showed significant decreases in carbon and oxygen and increases in calcium (p < 0.01). It was concluded that filling uninstrumented root canals with NaClO and using electrical conduction for 5 s could incinerate and eliminate the organic material of the root canal wall. The application of high-frequency electric current may lead to the cure of many cases of persistent apical periodontitis.
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Affiliation(s)
- Hiromichi Kumagai
- Department of Periodontology and Endodontology, Faculty of Dental Medicine, Hokkaido University, N13W7, Kita-ku, Sapporo 060-8586, Hokkaido, Japan
| | - Tsutomu Sugaya
- Department of Periodontology and Endodontology, Faculty of Dental Medicine, Hokkaido University, N13W7, Kita-ku, Sapporo 060-8586, Hokkaido, Japan
| | - Toshihiko Tominaga
- Department of Periodontology and Endodontology, Faculty of Dental Medicine, Hokkaido University, N13W7, Kita-ku, Sapporo 060-8586, Hokkaido, Japan
- Tominaga Dental Clinic, Setotyomyoujinshitahonjo 197-3, Naruto 771-0360, Tokushima, Japan
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Chi Y, Wang X, Li F, Zhang Z, Tan P. Aerospace Technology Improves Fermentation Potential of Microorganisms. Front Microbiol 2022; 13:896556. [PMID: 35572688 PMCID: PMC9106405 DOI: 10.3389/fmicb.2022.896556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 03/29/2022] [Indexed: 11/30/2022] Open
Abstract
It is highly possible to obtain high-quality microbial products in appreciable amounts, as aerospace technology is advancing continuously. Genome-wide genetic variations in microorganisms can be triggered by space microgravity and radiation. Mutation rate is high, mutant range is wide, and final mutant character is stable. Therefore, space microorganism breeding is growing to be a new and promising area in microbial science and has greatly propelled the development of fermentation technology. Numerous studies have discovered the following improvements of fermentation potential in microorganisms after exposure to space: (1) reduction in fermentation cycle and increase in growth rate; (2) improvement of mixed fermentation species; (3) increase in bacterial conjugation efficiency and motility; (4) improvement of the bioactivity of various key enzymes and product quality; (5) enhancement of multiple adverse stress resistance; (6) improvement of fermentation metabolites, flavor, appearance, and stability. Aerospace fermentation technology predominantly contributes to bioprocessing in a microgravity environment. Unlike terrestrial fermentation, aerospace fermentation keeps cells suspended in the fluid medium without significant shear forces. Space radiation and microgravity have physical, chemical, and biological effects on mutant microorganisms by causing alternation in fluid dynamics and genome, transcriptome, proteome, and metabolome levels.
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Affiliation(s)
- Yan Chi
- Wuzhoufeng Agricultural Science and Technology Co., Ltd., Yantai, China
| | - Xuejiang Wang
- Wuzhoufeng Agricultural Science and Technology Co., Ltd., Yantai, China
| | - Feng Li
- Wuzhoufeng Agricultural Science and Technology Co., Ltd., Yantai, China
| | - Zhikai Zhang
- Wuzhoufeng Agricultural Science and Technology Co., Ltd., Yantai, China
| | - Peiwen Tan
- Department of Computer Science, University of California, Irvine, Irvine, CA, United States
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Lazra Y, Gandu B, Amar ID, Emanuel E, Cahan R. Effects of Atmospheric Plasma Corona Discharge on Agrobacterium tumefaciens Survival. Microorganisms 2021; 10:microorganisms10010032. [PMID: 35056481 PMCID: PMC8780683 DOI: 10.3390/microorganisms10010032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 12/20/2021] [Accepted: 12/22/2021] [Indexed: 11/16/2022] Open
Abstract
Soil-borne pathogenic microorganisms are known to cause extensive crop losses. Agrobacterium tumefaciens, a member of the Proteobacteria, causes the neoplastic crown gall disease in plants. Plant protection is mainly based on toxic chemicals that are harmful to the environment. The use of cold atmospheric-pressure plasma is an attractive method for microbial eradication. Its antimicrobial mechanism includes the formation of large quantities of reactive oxygen species (ROS). The advantages of eradicating bacteria using cold plasma are not needed for chemicals, short treatment, and environmental temperatures. This study examined the impact of plasma corona discharge exposure on A. tumefaciens viability, membrane permeability, relative cell size, and ROS formation. The results showed that 90 s of plasma exposure led to a reduction by four orders of magnitude when the initial concentration was 1 × 107 CFU/mL and in a dry environment. When the initial concentration was 1 × 106 CFU/mL, 45 s of exposure resulted in total bacterial eradication. In a liquid environment, in an initial concentration of 2.02 × 106 CFU/mL, there was no complete bacterial eradication even at the most prolonged examined exposure (90 s). The influence of plasma treatment on the membrane permeability of A. tumefaciens, and their possible recovery, were analyzed using flow cytometer analysis using propidium iodide (PI). When the plasma-treated bacteria were suspended in Luria–Bertani (LB) (rich medium), the PI-positive count of the plasma-treated bacteria after two hours was 12 ± 3.9%. At the 24th hour, this percentage was only 1.74 ± 0.6%, as the control (0.7 ± 0.1%). These results may indicate the repair of the plasma-treated bacteria that were suspended in LB. At the 24th hour, the relative cell size of the treated bacteria shifted to the right, to ~3 × 104 forward side scatter (FSC), about 0.5-fold higher than the untreated cells. Measurement of the ROS showed that the intracellular fluorescence of the 90-s plasma-treated cells led to significant fluorescence formation of 32 relative fluorescence units (RFU)/cell (9 × 104 fold, compared to the nontreated cells). This study showed that cold plasma is a useful method for A. tumefaciens eradication. The eradication mechanism involves ROS generation, membrane permeability, and changes in cell size.
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Affiliation(s)
- Yulia Lazra
- Department of Chemical Engineering and Biotechnology, Ariel University, Ariel 40700, Israel; (Y.L.); (B.G.); (I.D.A.); (E.E.)
| | - Bharath Gandu
- Department of Chemical Engineering and Biotechnology, Ariel University, Ariel 40700, Israel; (Y.L.); (B.G.); (I.D.A.); (E.E.)
- Department of Environmental Studies, University of Delhi, New Delhi 110007, India
| | - Irina Dubrovin Amar
- Department of Chemical Engineering and Biotechnology, Ariel University, Ariel 40700, Israel; (Y.L.); (B.G.); (I.D.A.); (E.E.)
| | - Efrat Emanuel
- Department of Chemical Engineering and Biotechnology, Ariel University, Ariel 40700, Israel; (Y.L.); (B.G.); (I.D.A.); (E.E.)
| | - Rivka Cahan
- Department of Chemical Engineering and Biotechnology, Ariel University, Ariel 40700, Israel; (Y.L.); (B.G.); (I.D.A.); (E.E.)
- Correspondence: ; Tel.: +972-54-774-0293
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