Recent Advances and Potential Applications of Atmospheric Pressure Cold Plasma Technology for Sustainable Food Processing

Comprehensive review for aflatoxin detoxification with special attention to cold plasma treatment

Aflatoxins are potent carcinogens and pose significant risks to food safety and public health worldwide. Aflatoxins include Aflatoxin B1 (AFB1), Aflatoxin B2 (AFB2), Aflatoxin G1 (AFG1), Aflatoxin G2 (AFG2), and Aflatoxin M1 (AFM1). AFB1 is particularly notorious for its carcinogenicity, classified as a Group 1 human carcinogen by the International Agency for Research on Cancer (IARC). Chronic exposure to aflatoxins through contaminated food and feed can lead to liver cancer, immunosuppression, growth impairment, and other systemic health issues. Efforts to mitigate aflatoxin contamination have traditionally relied on chemical treatments, physical separation methods, and biological degradation. However, these approaches often pose challenges related to safety, efficacy, and impact on food quality. Recently, cold plasma treatment has emerged as a promising alternative. Cold plasma generates reactive oxygen species, which effectively degrade aflatoxins on food surfaces without compromising nutritional integrity or safety. This review consolidates current research and advancements in aflatoxin detoxification, highlighting the potential of cold plasma technology to revolutionize food safety practices. By exploring the mechanisms of aflatoxin toxicity, evaluating existing detoxification methods, and discussing the principles and applications of cold plasma treatment.

Rapid penetrating inactivation and disinfection through ice layers by light-condensed deep ultraviolet LED irradiation

The longer survival of virus and bacteria under low temperature greatly accelerates the infection risk and duration. How to effectively and rapidly inactivate them beneath ice layer in cold chain logistics has been an important issue never being well studied. Here, we demonstrate a novel light condenser design of high power UVC-LED device for rapid penetrating inactivation through ice layers. With fish-scale, ellipsoidal and alumina coated condenser, a portable UVC (275 nm) LED device in ultrahigh light output power (> 3 W) was fabricated in a narrowed propagation angle (< 60o). Such condensed light beams are able to overcome the interfacial refringence at the ice and bubble interfaces in different types of ice layers for enhancing the transmission rate. As a result, the penetrating UVC light could give rise to the effective necrosis and apoptosis influence as well as DNA/RNA destruction on cells. A 99.99 % inactivation rate of Escherichia coli and Staphylococcus aureus has been obtained through 5-mm-thickness opaque ice layer. By 1.5 s irradiation, SARS-COV-2 virus can be completely inactivated and disinfected. This work proved the strong power of UVC-LED for cold chain disinfection applications.

Advanced extraction of Glycyrrhiza glabra root extract using a combined ultrasonic and cold plasma reactor

Liquorice (Glycyrrhiza glabra L.) root extract has been used as a natural medicine and sweetener for a long time in many parts of the world. As a result, there has been a considerable emphasis on developing efficient and environmentally friendly methods for extracting bioactive components from Liquorice root. This work aims to examine extracting extract from Liquorice root using a combined ultrasonic-cold plasma reactor to elevate the extraction efficiency. Different parameters, including extraction time, ultrasonic power, and the argon-to-air ratio, were investigated using the Response Surface Methodology (RSM) and Box-Behnken design to raise extract quality. The total phenol and flavonoid content and antioxidant activity were calculated to evaluate this approach, and Glycyrrhizic acid content was quantified by HPLC (High-performance liquid chromatography). Results showed that combining ultrasonic-cold plasma extraction greatly raised the yield of extract and bioactive components compared to conventional maceration and single-method methods. Particularly, The content of total phenol 10.23, 15.96, and 13.29%, total flavonoid content 21.47, 22.19, and 42.41%, and Glycyrrhizic acid 10.84%, 12.38%, and 15.89% increased by ultrasonic, cold plasma, and combined ultrasonic-cold plasma technique, respectively, compared to the maceration technique. Optimization of different extraction techniques showed that the best extract quality came from a mix of ultrasonic power, plasma composition, and extraction time. This study demonstrates that the combined ultrasonic-cold plasma technique is effective and efficient, and this technology has the potential for a new extraction method to present a more sustainable and effective substitute for premium Liquorice extracts for medicinal and commercial uses.

Recent advances in cold plasma technology for enhancing the safety and quality of meat and meat products: A comprehensive review

Meat and meat products constitute an important component of the diet for several populations around the world and fulfill various nutritional requirements of the human body. However, owing to the inherent characteristics of meat - including its susceptibility to oxidation and contamination with foodborne pathogens - meat and meat products perish easily. In recent years, with improvements in living standards and increased focus on nutrition and health among consumers, non-thermal food processing technologies have received increasing attention. Among these strategies, cold plasma (CP) technology has emerged as a promising and novel processing technique with substantial potential in preserving meat and meat products. In this review, we discussed and analyzed the effects of CP on the nutritional value, sensory quality, and safety of meat and meat products, particularly, the potential toxicological hazards. Furthermore, we provided a detailed introduction to the mechanisms about how CP affects microorganisms, highlighting its role in inducing apoptosis and inhibiting quorum sensing. In the base of these theoretical foundations, this paper proposed several practical recommendations in order to optimize CP technology. Finally, we summarized the potential applications of CP in meat preservation, aiming to establish a theoretical framework for further research and application of this technology.

Cold plasma technology: A cutting-edge approach for enhancing shrimp preservation

Cold plasma (CP) is an emerging technology employed to safeguard highly perishable food items, particularly aquatic products such as shrimp. Due to its significant amount of moisture, superior protein composition that contains important amino acids, and unsaturated fatty acid content, shrimp are susceptible to microbial deterioration and overall alterations in their physical and chemical characteristics. Such spoilage not only diminishes the nutritional value of shrimp but also has the potential to generate harmful substances, rendering it unsuitable for consumption. Recent observations have indicated a growing market demand for shrimp that maintains its quality and has a prolonged shelf life. Furthermore, there is a significant emphasis on the production of food items that undergo minimal processing or nonthermal preservation methods. Extensive documentation exists regarding the efficacy of CP technology in eliminating microorganisms from shrimp without inducing resistance or activating enzymes that contribute to shrimp spoilage. Therefore, CP can be mentioned as a slight processing interference to preserve shrimp quality. This chapter primarily explores the principles and methods of CP technology, as well as its impact on melanosis, physicochemical changes, microbial and sensory properties, and the preservation of shrimp quality.

Essentials and Pertinence of Cold Plasma in Essential Oils, Metal-Organic Frameworks and Agriculture

Cold atmospheric pressure plasma (CAPP) comprises an ensemble of ionized gas, neutral particles, and/or reactive species. Electricity is frequently used to produce CAPP via a variety of techniques, including plasma jets, corona discharges, dielectric barrier discharges, and glow discharges. The type and flow rates of the carrier gas(es), temperature, pressure, and vacuum can all be altered to control the desired properties of the CAPP. Since a few decades ago, CAPP has become a widely used technology with applications in every walk of life. The plasma activated liquid mediums like water, ethanol, and methanol have been merged as novel sterilizers. With recent advancements in material science, particularly work on metal-organic frameworks (MOFs), essential oils, and agricultural technologies, CAPP has become a vital component of these advancements. Likewise, CAPP has been found as a green and benign technology to induce early seed germination and plant development. This review covers the critical components of CAPP, the production of reactive oxygen and nitrogen species, and mechanisms by which CAPP-based technologies are applied to agricultural products, MOFs, and essential oils.

Added insult to injury? The response of meat-associated pathogens to proposed antimicrobial interventions

Modern requirements for 'green label' meat products have led to the design of novel antimicrobial innovations which prioritise quality, safety and longevity. Plasma-functionalised water (PFW), ultraviolet light and natural antimicrobial compositions have been investigated and optimised for control of foodborne pathogens like Campylobacter jejuni and Salmonella enterica serovar Typhimurium. However, given the adaptive mechanisms present in bacteria under external stresses, it is imperative to understand the effect that sublethal treatment may have on the bacterial transcriptome. In this study, Salmonella Typhimurium and C. jejuni were treated with sublethal doses of ultraviolet light, a citrus juice/essential oil marinade, and 'spark' or 'glow' cold plasma generation system-produced PFW. Immediately after treatment, cells were lysed and RNA was extracted and purified. mRNA was converted to cDNA by reverse transcription-PCR and sequenced by an Illumina MiSeq® system. Sequences were filtered and analysed using the Tuxedo workflow. Sublethal treatment of Campylobacter jejuni and Salmonella Typhimurium led to increased immediate cellular and metabolic activity, as well as diversification in protein and metabolic functioning. There was further expression of pathogenesis and virulence-associated traits associated with spark PFW and marinade treatment of Salmonella Typhimurium. However, similar concerns were not raised with glow PFW or UV-treated samples. This study provides science-based evidence of the efficacy of multi-hurdle antimicrobial system using green-label marinades and PFW or UV to inactivate pathogens without upregulating virulence traits in surviving cells. This study will inform policymakers and food industry stakeholders and reinforces the need to incorporate in-line novel technologies to ensure consumer safety. KEY POINTS: • Salmonella and C. jejuni showed increased cell activity in immediate response to stress. • Virulence genes showed increased expression when treated with natural antimicrobials and sPFW. • Reduced immediate transcriptomic response to gPFW and UV treatment indicates lower risk.

Cold plasma technology: does it have a place in food processing?

In recent years, there has been a growing demand for alternative food processing technologies that can improve food safety while preserving the nutritional quality of food products. Traditional thermal processing methods can lead to nutrient loss and degradation, prompting the exploration of novel approaches. Cold plasma (CP) technology, an emerging non-thermal food processing technique, has gained significant attention for its potential in the food industry. We provide herein, an introduction to CP and an overview of the technology, highlighting its potential advantages in safety, efficiency, and environmental friendliness.

Innovative Pathogen Reduction in Exported Sea Bass Through Atmospheric Cold Plasma Technology

The safety of sea bass is critical for the global food trade. This study evaluated the effectiveness of atmospheric cold plasma in reducing food safety risks posed by Salmonella Enteritidis and Listeria monocytogenes, which can contaminate sea bass post harvest. Cold plasma was applied to inoculated sea bass for 2 to 18 min, achieving a maximum reduction of 1.43 log CFU/g for S. Enteritidis and 0.80 log CFU/g for L. monocytogenes at 18 min. Longer treatments resulted in greater reductions; however, odor and taste quality declined to a below average quality in samples treated for 12 min or longer. Plasma treatment did not significantly alter the color, texture, or water activity (aw) of the fish. Higher levels of thiobarbituric acid reactive substances (TBARSs) were observed with increased exposure times. Cold plasma was also tested in vitro on S. Enteritidis and L. monocytogenes on agar surfaces. A 4 min treatment eliminated the initial loads of S. Enteritidis (2.71 log CFU) and L. monocytogenes (2.98 log CFU). The findings highlight the potential of cold plasma in enhancing the safety of naturally contaminated fish. Cold plasma represents a promising technology for improving food safety in the global fish trade and continues to be a significant area of research in food science.

Acid Adaptation Enhances Tolerance of Escherichia coli O157:H7 to High Voltage Atmospheric Cold Plasma in Raw Pineapple Juice

Pathogens that adapt to environmental stress can develop an increased tolerance to some physical or chemical antimicrobial treatments. The main objective of this study was to determine if acid adaptation increased the tolerance of Escherichia coli O157:H7 to high voltage atmospheric cold plasma (HVACP) in raw pineapple juice. Samples (10 mL) of juice were inoculated with non-acid-adapted (NAA) or acid-adapted (AA) E. coli to obtain a viable count of ~7.00 log10 CFU/mL. The samples were exposed to HVACP (70 kV) for 1-7 min, with inoculated non-HVACP-treated juice serving as a control. Juice samples were analyzed for survivors at 0.1 h and after 24 h of refrigeration (4 °C). Samples analyzed after 24 h exhibited significant decreases in viable NAA cells with sub-lethal injury detected in both NAA and AA survivors (p < 0.05). No NAA survivor in juice exposed to HVACP for 5 or 7 min was detected after 24 h. However, the number of AA survivors was 3.33 and 3.09 log10 CFU/mL in juice treated for 5 and 7 min, respectively (p < 0.05). These results indicate that acid adaptation increases the tolerance of E. coli to HVACP in pineapple juice. The potentially higher tolerance of AA E. coli O157:H7 to HVACP should be considered in developing safe juice processing parameters for this novel non-thermal technology.

From field to table: Ensuring food safety by reducing pesticide residues in food

The present review addresses the significance of lowering pesticide residue levels in food items because of their harmful impacts on human health, wildlife populations, and the environment. It draws attention to the possible health risks-acute and chronic poisoning, cancer, unfavorable effects on reproduction, and harm to the brain or immunological systems-that come with pesticide exposure. Numerous traditional and cutting-edge methods, such as washing, blanching, peeling, thermal treatments, alkaline electrolyzed water washing, cold plasma, ultrasonic cleaning, ozone treatment, and enzymatic treatment, have been proposed to reduce pesticide residues in food products. It highlights the necessity of a paradigm change in crop protection and agri-food production on a global scale. It offers opportunities to guarantee food safety through the mitigation of pesticide residues in food. The review concludes that the first step in reducing worries about the negative effects of pesticides is to implement regulatory measures to regulate their use. In order to lower the exposure to dietary pesticides, the present review also emphasizes the significance of precision agricultural practices and integrated pest management techniques. The advanced approaches covered in this review present viable options along with traditional methods and possess the potential to lower pesticide residues in food items without sacrificing quality. It can be concluded from the present review that a paradigm shift towards sustainable agriculture and food production is essential to minimize pesticide residues in food, safeguarding human health, wildlife populations, and the environment. Furthermore, there is a need to refine the conventional methods of pesticide removal from food items along with the development of modern techniques.

Exploring the effects of non-thermal plasma pre-treatment on coriander (Coriander sativum L.) seed germination efficiency

This study investigates the effects of non-thermal plasma (NTP) treatment on the germination characteristics of coriander seeds (Coriandrum sativum L.). Different germination factors, water imbibition rate and changes in mass, were analyzed. The results indicate that a suitable duration of NTP treatment (180 s and 300 s) enhances seed germination characteristics, whereas prolonged exposure (420 s) leads to adverse effects. Furthermore, shorter NTP exposures (180 s) improved water absorption and surface properties of seeds, while longer exposures (420 s) caused mass loss and compromised seed vigor. Overall, the findings demonstrate the significance of optimizing NTP treatment conditions for enhancing seed germination characteristics.

Application of cold argon plasma on germination, root length, and decontamination of soybean cultivars

Applying cold discharge plasma can potentially alter plants' germination characteristics by triggering their physiological activities. As a main crop in many countries, soybean was examined in the present study using cultivars such as Arian, Katoul, Saba, Sari, and Williams in a cold argon plasma. This study has been motivated by the importance of plant production worldwide, considering climate change and the increasing needs of human populations for food. This study was performed to inspect the effect of cold plasma treatment on seed germination and the impact of argon plasma on microbial decontamination was investigated on soybeans. Also, the employed cultivars have not been studied until now the radicals generated from argon were detected by optical emission spectrometry (OES), and a collisional radiative model was used to describe electron density. The germination properties, including final germination percentage (FGP), mean germination time (MGT), root length, and electrical conductivity of biomolecules released from the seeds, were investigated after the plasma treatments for 30, 60, 180, 300, and 420 s. The decontamination effect of the plasma on Aspergillus flavus (A.flavus) and Fusarium solani (F.solani) was also examined. The plasma for 60 s induced a maximum FGP change of 23.12 ± 0.34% and a lowest MGT value of 1.40 ± 0.007 days. Moreover, the ultimate root length was 56.12 ± 2.89%, in the seeds treated for 60 s. The plasma exposure, however, failed to yield a significant enhancement in electrical conductivity, even when the discharge duration was extended to 180 s or longer. Therefore, the plasma duration of 180 s was selected for the blotter technique. Both fungi showed successful sterilization; their infectivity inhibition was 67 ± 4 and 65 ± 3.1%, respectively. In general, the cold plasma used for soybeans in the present study preserved their healthy qualities and reduced the degree of fungal contamination.

Cold atmospheric plasma for surface disinfection: a promising weapon against deleterious meticillin-resistant Staphylococcus aureus biofilms

BACKGROUND

Bacteria are becoming increasingly resistant to classical antimicrobial agents, so new approaches need to be explored.

AIM

To assess the potential of cold atmospheric plasma for the management of meticillin-resistant Staphylococcus aureus (MRSA).

METHODS

The 24, 48, and 72 h resistant and susceptible S. aureus biofilms were exposed to 60, 120, and 180 s treatment with plasma.

FINDINGS

Increasing the treatment time results in higher cell reduction for both susceptible and resistant strains of S. aureus (P < 0.05). Up to log10 reduction factor of 5.24 cfu/cm2 can be achieved in 180 s of plasma treatment. Furthermore, plasma can substantially alter the cell's metabolisms and impact cell membrane integrity. However, it has not been shown that plasma can reduce biofilm biomass in the case of 24 h and 48 h biofilms, although the 72 h biofilm was more susceptible, and its biomass was decreased (P < 0.05). The accumulation of intrabacterial reactive oxygen species was also observed, which confirms the plasma's induction of oxidative stress. Finally, it was shown that continuous plasma exposure of bacterial cells does not cause resistance to plasma, nor is resistance developed to cefoxitin.

CONCLUSION

Cold atmospheric plasma is a good candidate for S. aureus and MRSA biofilm treatment and may therefore be of value in the bacterial resistance crisis.

Changes in Flavor and Volatile Composition of Meat and Meat Products Observed after Exposure to Atmospheric Pressure Cold Plasma (ACP)

Studies on the atmospheric pressure cold plasma (ACP) exposure of meat and meat products mainly determine microbial inactivation, lipid oxidation, and meat color. Some studies include sensory evaluation, but only a few determine the changes in volatile composition due to ACP treatment. The results of sensory evaluation are inconclusive and range from "improvement" to "off-odor". This could be due to differences in the food matrix, especially in processed foods, or different experimental settings, including inadvertent effects such as sample heating. The few studies analyzing volatile composition report changes in alcohols, esters, aldehydes, and other compounds, but not necessarily changes that are novel for meat and meat products. Most studies do not actually measure the formation of reactive species, although this is needed to determine the exact reactions taking place in the meat during ACP treatment. This is a prerequisite for an adjustment of the plasma conditions to achieve antimicrobial effects without compromising sensory quality. Likewise, such knowledge is necessary to clarify if ACP-exposed meat and products thereof require regulatory approval.

Cold Plasma-Assisted Extraction of Phytochemicals: A Review

In recent years, there has been growing interest in bioactive plant compounds for their beneficial effects on health and for their potential in reducing the risk of developing certain diseases such as cancer, cardiovascular diseases, and neurodegenerative disorders. The extraction techniques conventionally used to obtain these phytocompounds, however, due to the use of toxic solvents and high temperatures, tend to be supplanted by innovative and unconventional techniques, in line with the demand for environmental and economic sustainability of new chemical processes. Among non-thermal technologies, cold plasma (CP), which has been successfully used for some years in the food industry as a treatment to improve food shelf life, seems to be one of the most promising solutions in green extraction processes. CP is characterized by its low environmental impact, low cost, and better extraction yield of phytochemicals, saving time, energy, and solvents compared with other classical extraction processes. In light of these considerations, this review aims to provide an overview of the potential and critical issues related to the use of CP in the extraction of phytochemicals, particularly polyphenols and essential oils. To review the current knowledge status and future insights of CP in this sector, a bibliometric study, providing quantitative information on the research activity based on the available published scientific literature, was carried out by the VOSviewer software (v. 1.6.18). Scientometric analysis has seen an increase in scientific studies over the past two years, underlining the growing interest of the scientific community in this natural substance extraction technique. The literature studies analyzed have shown that, in general, the use of CP was able to increase the yield of essential oil and polyphenols. Furthermore, the composition of the phytoextract obtained with CP would appear to be influenced by process parameters such as intensity (power and voltage), treatment time, and the working gas used. In general, the studies analyzed showed that the best yields in terms of total polyphenols and the antioxidant and antimicrobial properties of the phytoextracts were obtained using mild process conditions and nitrogen as the working gas. The use of CP as a non-conventional extraction technique is very recent, and further studies are needed to better understand the optimal process conditions to be adopted, and above all, in-depth studies are needed to better understand the mechanisms of plasma-plant matrix interaction to verify the possibility of any side reactions that could generate, in a highly oxidative environment, potentially hazardous substances, which would limit the exploitation of this technique at the industrial level.

Detoxification of the post-harvest antifungal pesticide thiabendazole by cold atmospheric plasma

Cold atmospheric plasma (CAP) irradiation has a sterilizing effect without thermal denaturation or the production of residual substances. Hence, it is considered to be a safe sterilization technology with minimal damage for fresh foods. In addition, its decomposition effect on chemical substances has also been confirmed, and the application of CAP in the food and agricultural domains is increasing. In this study, we examined the potential of CAP to detoxify pesticide residues. Post-harvest chemical treatments using pesticides, such as fungicides, are frequently employed in imported agricultural products and are often disapproved by consumers. Therefore, we assessed the detoxification of thiabendazole (TBZ), a widely used post-harvest pesticide, using low-cost air plasma irradiation. We found that CAP irradiation conditions that detoxified TBZ caused little damage to the edible parts of mandarin oranges. The results of the present study suggest that CAP irradiation is useful for detoxifying and degrading pesticide residues without damaging agricultural products and that CAP irradiation is an effective means of maintaining food safety.

Effects of cold atmospheric plasma on endogenous enzyme activity and muscle protein oxidation in Trachinotus ovatus

In this study, we investigated the effects of cold atmospheric plasma (CAP) technology on endogenous enzyme characteristics and muscle protein properties of the golden pomfret (Trachinotus ovatus) under different treatment power and time conditions. Results showed that the enzymatic activity of cathepsin B, L, and calpain in crude protease extracts (CPE) decreased significantly as the treatment power and treatment time of CAP increased (p < 0.05). Oxidative degradation of the CPE after exposure to CAP resulted in significant changes in the structure, total sulfhydryl, and carbonyl content of the CPE (p < 0.05). CAP of an appropriate intensity resulted in significant improvements in the color parameters, hydration properties, and textural property parameters of muscle proteins (p < 0.05). These results suggest that CAP, as a non-thermophysical modification technique, can inhibit the activity of endogenous enzymes as well as alter the protein function in food.