Mitigating polyethylene-mediated periprosthetic tissue inflammation through MEDSAH-grafting.

Periprosthetic tissue inflammation is a challenging complication arising in joint replacement surgeries, which is often caused by wear debris from polyethylene (PE) components. In this study, we examined the potential biological effects of grafting a [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (MEDSAH) polymer onto the surface of PE through a solvent-evaporation technique. J774A.1 macrophage-like cells and primary cultured mouse osteoblasts were treated with PE powder with or without the MEDSAH coating. MEDSAH grafting on PE substantially reduced the expression of pro-inflammatory cytokines and other mediators in primary cultured mouse osteoblasts, but did not significantly impact macrophage-mediated inflammation. Our findings suggest that a MEDSAH coating on PE-based materials has potential utility in mitigating periprosthetic tissue inflammation and osteolysis and preventing aseptic loosening in total joint replacements. Further research, including large-scale clinical trials and biomechanical analyses, is needed to assess the long-term performance and clinical implications of MEDSAH-coated PE-based materials in total joint arthroplasty.

Control of artificial membrane fusion in physiological ionic solutions beyond the limits of electroformation.

Membrane fusion, merging two lipid bilayers, is crucial for fabricating artificial membrane structures. Over the past 40 years, in contrast to precise and controllable membrane fusion in-vivo through specific molecules such as SNAREs, controlling the fusion in-vitro while fabricating artificial membrane structures in physiological ionic solutions without fusion proteins has been a challenge, becoming a significant obstacle to practical applications. We present an approach consisting of an electric field and a few kPa hydraulic pressure as an additional variable to physically control the fusion, enabling tuning of the shape and size of the 3D freestanding lipid bilayers in physiological ionic solutions. Mechanical model analysis reveals that pressure-induced parallel/normal tensions enhance fusion among membranes in the microwell. In-vitro peptide-membrane assay, mimicking vesicular transport via pressure-assisted fusion, and stability of 38 days with in-chip pressure control via pore size-regulated hydrogel highlight the potential for diverse biological applications.

Association of salivary testosterone levels during the post-awakening period with age and symptoms suggestive of late-onset hypogonadism in men.

BACKGROUND: The lack of association between serum testosterone levels and symptoms suggestive of hypogonadism is a significant barrier in the determination of late-onset hypogonadism (LOH) in men. This study explored whether testosterone levels increase after morning awakening, likewise the cortisol awakening response (CAR) in the hypothalamic-pituitary-adrenal (HPA) axis, and whether testosterone levels during the post-awakening period are associated with age and symptoms suggestive of late-onset hypogonadism (LOH) in men. METHODS: Testosterone and cortisol levels were determined in saliva samples collected immediately upon awakening and 30 and 60 min after awakening, and scores of the Aging Males' Symptoms (AMS) questionnaire were obtained from 225 healthy adult men. RESULTS: A typical CAR (an increase in cortisol level ≥ 2.5 nmol/L above individual baseline) was observed in 155 participants (the subgroup exhibiting typical CAR). In the subgroup exhibiting CAR, testosterone levels sharply increased during the post-awakening period, showing a significant negative correlation with age, total AMS score, and the scores of 11 items on the somatic, psychological, and sexual AMS subscales. Of these items, three sexual items (AMS items #15-17) were correlated with age. Meanwhile, there was no notable increase in testosterone levels and no significant correlation of testosterone levels with age and AMS score in the subgroup exhibiting no typical CAR (n = 70). CONCLUSIONS: The results indicate that the hypothalamus-pituitary-gonad (HPG) axis responds to morning awakening, and determining testosterone levels during the post-awakening period in men with typical CAR may be useful for assessing HPG axis function and LOH.

The present study found that the HPG axis in healthy adult men responds to the morning awakening, characterized by increased salivary testosterone levels after the awakening period.The levels of salivary testosterone during the first hour after awakening are negatively associated with age and the severity of symptoms suggestive of LOH in adult men with typical CAR.

Development and investigation of ultrasound-assisted pulsed ohmic heating for inactivation of foodborne pathogens in milk with different fat content.

The central objective of this research was to develop an ultrasound-assisted pulsed ohmic heating (POH) system for inactivation of food-borne pathogens in phosphate buffered saline (PBS) and milk with 0-3.6% fat and investigate its bactericidal effect. Combining ultrasound with POH did not significantly affect the temperature profile of samples. Both POH alone and ultrasound-assisted POH took 120 s to heat PBS 60℃. Milk with 0, 1, and 3.6% fat was heated to 60℃ by POH alone and ultrasound-assisted POH after 335, 475, and 525 s, respectively. This is because the electrical conductivity of the samples was the same for POH alone and ultrasound-assisted POH. Despite identical temperature profiles, ultrasound-assisted POH exerted a synergistic effect on the reduction of Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes, and Staphylococcus aureus. In particular, the inactivation level of S. Typhimurium in PBS subjected to ultrasound-assisted POH treatment for 120 s corresponding to a treatment temperature of 60℃ was 3.73 log units higher than the sum of each treatment alone. A propidium iodide assay, intracellular protein measurements, and scanning electron microscopy revealed that ultrasound-assisted POH treatment provoked lethal cell membrane damage and leakage of intracellular proteins. Meanwhile, fat in milk reduced the efficacy of the bacterial inactivation of the ultrasound-assisted POH system due to its low electrical conductivity and sonoprotective effect. After ultrasound-assisted POH treatment at 60℃, there were no significant differences (P > 0.05) in the pH, color, and apparent viscosity of milk between the untreated and treated group.

Airborne survival and stress response in Listeria monocytogenes across different growth temperatures.

In the food industry, ensuring food safety during transportation and storage is vital, with temperature regulation preventing spoilage. However, airborne contamination through foodborne pathogens remains a concern. Listeria monocytogenes, a psychrotolerant foodborne pathogen, has been linked to various foodborne outbreaks. Therefore, understanding how its airborne characteristics depend on the growth temperature is imperative. As a result, when the L. monocytogenes was floated in air for 30 and 60 min, the surviving population of 15 °C-grown L. monocytogenes that was suspended in air and attached on the surface was significantly higher than L. monocytogenes grown at 25°C and 37 °C. The fatty acid analysis revealed a significantly higher proportion of shorter chain fatty acids in L. monocytogenes grown at 15 °C compared to those grown at 37 °C. Under aerosolization, L. monocytogenes encountered osmotic and cold stresses regardless of their growth temperature. Transcriptomic analysis showed that stress response related genes, such as oxidative and cold stress response, as well as PTS system related genes were upregulated at 15 °C, resulting in the enhanced resistance to various stresses during aerosolization. These results provide insights into the different responses of aerosolized L. monocytogenes according to the different growth temperatures, highlighting a critical factor in preventing airborne cross-contamination.

Lightweight Transformer Model for Mobile Application Classification.

Recently, realistic services like virtual reality and augmented reality have gained popularity. These realistic services require deterministic transmission with end-to-end low latency and high reliability for practical applications. However, for these real-time services to be deterministic, the network core should provide the requisite level of network. To deliver differentiated services to each real-time service, network service providers can classify applications based on traffic. However, due to the presence of personal information in headers, application classification based on encrypted application data is necessary. Initially, we collected application traffic from four well-known applications and preprocessed this data to extract encrypted application data and convert it into model input. We proposed a lightweight transformer model consisting of an encoder, a global average pooling layer, and a dense layer to categorize applications based on the encrypted payload in a packet. To enhance the performance of the proposed model, we determined hyperparameters using several performance evaluations. We evaluated performance with 1D-CNN and ET-BERT. The proposed transformer model demonstrated good performance in the performance evaluation, with a classification accuracy and F1 score of 96% and 95%, respectively. The time complexity of the proposed transformer model was higher than that of 1D-CNN but performed better in application classification. The proposed transformer model had lower time complexity and higher classification performance than ET-BERT.

Application of combined treatment of peracetic acid and ultraviolet-C for inactivating pathogens in water and on surface of apples.

In this study, a combined treatment of peracetic acid (PAA) and 280 nm Ultraviolet-C (UVC) - Light emitting diode (LED) was applied for inactivating foodborne pathogens in water and apples. The combined treatment of PAA (50 ppm) and UVC-LED showed synergistic inactivation effects against Escherichia coli O157:H7 and Listeria monocytogenes in water. In mechanism analysis, PAA/UVC-LED treatment induced more lipid peroxidation, intracellular ROS, membrane, and DNA damage than a single treatment. Among them, membrane damage was the main synergistic inactivation mechanism of combination treatment. Cell rupture and shrink of both pathogens after PAA/UVC-LED treatment were also identified through scanning electron microscope (SEM) analysis. To examine inactivation of pathogens on the surface of apples by PAA, UVC-LED, and their combined treatment, a washing system (WS) was developed and used. Through applying the WS, PAA/UVC-LED treatment effectively inactivated two pathogens in washing solution and on the surface of apples below the detection limit (3.30 log CFU/2000 mL and 2.0 log CFU/apple) within 5 min. In addition, there was no significant difference in color or firmness of apples after PAA/UVC-LED treatment (p > 0.05).

Self-Assembled Skin-Penetrating Peptides with Controlled Supramolecular Properties for Enhanced Transdermal Delivery.

The use of nanocarriers decorated with penetration-enhancing agents (PEAs) is considered to be a promising approach for efficient transdermal delivery. In this study, we developed short amphiphilic skin-penetrating peptides (17 amino acids) that functioned not only as PEAs but also as building blocks of nanocarriers without the incorporation of additional macromolecules for self-assembly and guest molecule encapsulation. Interestingly, varying only two amino acids in the hydrophobic moiety of the peptides resulted in significantly different self-assembly behavior, thermal stability, protease resistance, and skin-penetration efficiency in a human skin model. The analysis of the peptide secondary structure revealed that such characteristic changes arose due to the sequence variation-mediated conformational change in the hydrophobic block. These findings hold significant promise for the development of simple and effective delivery systems exhibiting controllable supramolecular properties.

The Role of CPNE7 (Copine-7) in Colorectal Cancer Prognosis and Metastasis.

Colorectal cancer (CRC) is one of the most common and deadly cancers in the world. However, no effective treatment for the disease has yet been found. For this reason, several studies are being carried out on the treatment of CRC. Currently, there is limited understanding of the role of CPNE7 (copine-7) in CRC progression and metastasis. The results of this study show that CPNE7 exerts an oncogenic effect in CRC. First, CPNE7 was shown to be significantly up-regulated in CRC patient tissues and CRC cell lines compared to normal tissues according to IHC staining, qRT-PCR, and western blotting. Next, this study used both systems of siRNA and shRNA to suppress CPNE7 gene expression to check the CPNE7 mechanism in CRC. The suppressed CPNE7 significantly inhibited the growth of CRC cells in in vitro experiments, including migration, invasion, and semisolid agar colony-forming assay. Moreover, the modified expression of CPNE7 led to a decrease in the levels of genes associated with epithelial-mesenchymal transition (EMT). The epithelial genes E-cadherin (CDH1) and Collagen A1 were upregulated, and the levels of mesenchymal genes such as N-cadherin (CDH2), ZEB1, ZEB2, and SNAIL (SNAL1) were downregulated after CPNE7 inhibition. This study suggests that CPNE7 may serve as a potential diagnostic biomarker for CRC patients.

Comparison of the efficacy of physical and chemical strategies for the inactivation of biofilm cells of foodborne pathogens.

Biofilm formation is a strategy in which microorganisms generate a matrix of extracellular polymeric substances to increase survival under harsh conditions. The efficacy of sanitization processes is lowered when biofilms form, in particular on industrial devices. While various traditional and emerging technologies have been explored for the eradication of biofilms, cell resistance under a range of environmental conditions renders evaluation of the efficacy of control challenging. This review aimed to: (1) classify biofilm control measures into chemical, physical, and combination methods, (2) discuss mechanisms underlying inactivation by each method, and (3) summarize the reduction of biofilm cells after each treatment. The review is expected to be useful for future experimental studies and help to guide the establishment of biofilm control strategies in the food industry.

Inactivation of foodborne pathogens in ground pork tenderloin using 915 MHz microwave heating depending on power level.

The main purpose of this research was to investigate the effect of power level of 915 MHz microwave heating on the inactivation of foodborne pathogens in ground pork and its bactericidal mechanism. It was demonstrated that the heating rate was proportional to the power level. For instance, the heating rates observed at microwave heating powers of 2, 3, 4, and 5 kW were 1.70, 2.77, 3.35, and 4.03℃/s, respectively. The bactericidal effect of microwave heating also significantly (P < 0.05) increased with increasing power level. In particular, when ground pork was subjected to microwave heating at 5 kW, the reduction level of pathogens was>2 log units higher than at 2 kW. To determine the bactericidal mechanism of microwave heating depending on power level, changes in transmembrane potential and DNA damage were determined using fluorescence. The extent of depolarization in membrane potential of pathogens significantly (P < 0.05) increased as power level increased. There was no significant difference in degree of DNA damage at different power levels. However, the percentage of DNA damage was>86% at all power levels. The transmembrane potential assay indicates that the bacteria exhibited dramatic pore formation on the membrane at 5 kW. Through transmission electron microscopy, the electroporation effect was enhanced as power level increased. Moreover, the quality of ground pork subjected to microwave heating at 2-5 kW was determined by measuring the moisture content, cooking loss, and texture profile.

Sarcoma Immunotherapy: Confronting Present Hurdles and Unveiling Upcoming Opportunities.

Sarcomas are rare and heterogeneous mesenchymal neoplasms originating from the bone or soft tissues, which pose significant treatment challenges. The current standard treatment for sarcomas consists of surgical resection, often combined with chemo- and radiotherapy; however, local recurrence and metastasis remain significant concerns. Although immunotherapy has demonstrated promise in improving long-term survival rates for certain cancers, sarcomas are generally considered to be relatively less immunogenic than other tumors, presenting substantial challenges for effective immunotherapy. In this review, we examine the possible opportunities for sarcoma immunotherapy, noting cancer testis antigens expressed in sarcomas. We then cover the current status of immunotherapies in sarcomas, including progress in cancer vaccines, immune checkpoint inhibitors, and adoptive cellular therapy and their potential in combating these tumors. Furthermore, we discuss the limitations of immunotherapies in sarcomas, including a low tumor mutation burden and immunosuppressive tumor microenvironment, and explore potential strategies to tackle the immunosuppressive barriers in therapeutic interventions, shedding light on the development of effective and personalized treatments for sarcomas. Overall, this review provides a comprehensive overview of the current status and potential of immunotherapies in sarcoma treatment, highlighting the challenges and opportunities for developing effective therapies to improve the outcomes of patients with these rare malignancies.

Characteristics of Staphylococcus aureus biofilm matured in tryptic soy broth, low-fat milk, or whole milk samples along with inactivation by 405 nm light combined with folic acid.

In the present study, the characteristics of Staphylococcus aureus biofilms matured in tryptic soy broth (TSB), low-fat milk, or whole milk samples were identified along with their resistance to 405 nm light with or without folic acid. Phenotypic properties of carbohydrate and protein contents in extracellular polymeric substance (EPS) of S. aureus biofilms matured in different conditions were identified. The carbohydrate content was higher in the biofilm matured in low-fat milk (1.27) than the samples matured in whole milk (0.58) and TSB (0.10). Protein content in the EPS of biofilm was higher in the sample matured in whole milk (6.59) than the samples matured in low-fat milk (3.24) and TSB (2.08). Moreover, the maturation condition had a significant effect on the membrane lipid composition of the biofilm, producing more unsaturated fatty acids in biofilm matured in milk samples. These changes in biofilm matured in milk samples increased the resistance of S. aureus to 405 nm light in the presence of folic acid (LFA). Additionally, transcriptomic analysis was conducted to identify the response of S. aureus biofilm to LFA treatment. Several genes related to DNA and protein protection from oxidative stress along with biofilm accumulation were overexpressed in the LFA-treated biofilms. These results indicate the maturation of S. aureus biofilm in various samples and the biofilms responses to bactericidal treatments.

Phytochemical and functional characterization of fermented Yerba mate using Rhizopus oligosporus.

Solid-state fermentation (SSF) was used to enhance the bioactive compounds and biological properties of food materials, such as buckwheat, turmeric, and ginseng. This study was investigated the effects of SSF for up to 10 days using Rhizopus oligosporus on Yerba mate (Ilex paraguariensis St. Hilaire). The total phenolic content of Yerba mate rose to 20% after 1 day fermentation. The saponin contents of Yerba mate rose to 38% after 7 day fermentation. Furthermore, chlorogenic acid, caffeic acid, and caffeine levels were increased up to 27.74% by fermentation, as determined by UPLC-MS analysis. ORAC and FRAP assays showed that the antioxidant activities of Yerba mate were enhanced 1.9- and 1.14-fold after 1 day fermentation. In addition, its inhibitory activities against yeast α-glucosidase and nitric oxide release in LPS-stimulated RAW264.7 cells were higher than in the unfermented Yerba mate. Moreover, taste sensory analysis using an electronic tongue sensory system showed that the flavor of Yerba mate after 1 day fermentation was similar to that of the unfermented Yerba mate. These results suggested that solid fermentation using R. oligosporus is conducive to producing Yerba mate with enhanced biological properties.

Bacterial composition of refrigerators in households and inactivation of airborne Staphylococcus aureus using a TiO2-UVLED module in a 512 L aerobiology chamber.

This study aimed to investigate the microbiota in the air and on the surface of a refrigerator and to inactivate aerosolized Staphylococcus aureus using a TiO2-UVLED module. A total of 100 L of the air and 5000 cm2 surfaces in seven household refrigerators were collected using an air sampler and a swab, respectively. Samples were subjected to microbiota analysis as well as quantitative analyses of aerobic or anaerobic bacteria. The level of airborne aerobic bacteria was 4.26 log CFU/vol (100 L), while that of surface aerobic bacteria was 5.27 log CFU/surface (5000 cm2). PCoA based on the Bray-Curtis metric revealed that the bacterial composition differed between samples collected from refrigerators with and without a vegetable drawer. Moreover, pathogenic bacteria containing genera and order from each sample were found, such as Enterobacaterales, Pseudomonas, Staphylococcus, Listeria, and Bacillus. Among them, Staphylococcus aureus was determined to be a core hazardous pathogen in air. Therefore, three S. aureus strains isolated from the air in refrigerators, as well as a reference strain of S. aureus (ATCC 6538P), were inactivated by a TiO2-UVLED module in a 512 L aerobiology chamber. All aerosolized S. aureus were reduced over 1.6 log CFU/vol after treatment with TiO2 under UVA (365 nm) light at 40 J/cm2. These findings suggest that TiO2-UVLED modules have the potential to be used to control airborne bacteria in household refrigerators.

FragTracer: Real-Time Fragmentation Monitoring Tool for F2FS File System.

Emerging hardware devices (e.g., NVMe SSD, RISC-V, etc.) open new opportunities for improving the overall performance of computer systems. In addition, the applications try to fully utilize hardware resources to keep up with those improvements. However, these trends can cause significant file system overheads (i.e., fragmentation issues). In this paper, we first study the reason for the fragmentation issues on an F2FS file system and present a new tool, called FragTracer, which helps to analyze the ratio of fragmentation in real-time. For user-friendly usage, we designed FragTracer with three main modules, monitoring, pre-processing, and visualization, which automatically runs without any user intervention. We also optimized FragTracer in terms of performance to hide its overhead in tracking and analyzing fragmentation issues on-the-fly. We evaluated FragTracer with three real-world databases on the F2FS file system, so as to study the fragmentation characteristics caused by databases, and we compared the overhead of FragTracer. Our evaluation results clearly show that the overhead of FragTracer is negligible when running on commodity computing environments.

Simultaneous vacuum ultra violet-amalgam lamp radiation and near-infrared radiation heating for a synergistic bactericidal effect against Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium in black peppercorn.

This study evaluated the effect of simultaneous irradiation with vacuum ultraviolet (VUV)-amalgam lamp and near-infrared radiation (NIR) to inactivate foodborne pathogens in black peppercorn (Piper nigrum) while monitoring its piperine content and color. NIR treatment for 20 min caused an increase in black peppercorn temperature to 70 °C, and its bactericidal effect showed only 3.14 and 1.88 log reductions of Escherichia coli O157:H7 and Salmonella Typhimurium respectively. Single treatment with a VUV-amalgam lamp for 20 min achieved 2.26 and 1.55 log reductions of E. coli O157:H7 and S. Typhimurium, respectively. However, simultaneous treatment for 15 min produces a greater than 5-log reduction of both foodborne pathogens without changes of black peppercorn quality. The underlying bactericidal mechanism of the VUV-amalgam lamp is 254 nm irradiation with ozone generated by 185 nm irradiation. The ozone concentration was maintained with VUV-amalgam lamp single treatment but decreased during simultaneous treatment. In contrast, due to the drying effect of NIR irradiation, water vapor reacts with 185 nm irradiation or ozone to produce a variety of reactive oxygen species (ROS) such as hydrogen peroxide and hydroxyl radical during simultaneous treatment. The hydrogen peroxide concentration measured by Gastec increased during simultaneous treatment. We also investigated various generated types of ROS that can contribute to a synergistic bactericidal effect. We compared the bactericidal effect of sequential and simultaneous treatments with NIR and VUV-amalgam lamps to black peppercorn. Although sequential treatment showed additional inactivation efficacy, reductions of pathogens were significantly lower than with simultaneous treatment. These findings suggest that simultaneous VUV-amalgam lamp and NIR irradiation treatment via generation of ROS can increase bacterial inactivation efficacy of foodborne pathogens in black peppercorns without quality changes.

Synergistic effects of 915 MHz microwave heating and essential oils on inactivation of foodborne pathogen in hot-chili sauce.

Essential oil is a food additive with antimicrobial properties but with limitations due to strong organoleptic properties. However, thermal treatments can be applied to reduce essential oil content while ensuring antimicrobial activities in food matrices. In this study, the inactivation efficiency of essential oils on E. coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes in buffered peptone water (BPW) and hot-chili sauce was evaluated when coupled with 915 MHz microwave heating. Essential oils used in this study did not affect the dielectric properties and further heating rate of BPW and hot-chili sauce. The dielectric constant of BPW was 76.3 and dielectric loss factor was 30.9. In addition, it took 85 s to reach 100 °C for all samples. Among essential oils, synergistic microbial inactivation with microwave heating was observed from carvacrol (CL) and citral (CI), but not from eugenol (EU) and Carvone (CN). Specifically, CL and microwave heating (M) for 45 s showed the most effective inactivation (ca. 6 log reduction) for the pathogens in BPW. Similar trends were shown in hot-chili sauce. However, M + CI inactivation did not show synergistic effects in hot-chili sauce. Microwave heating time for hot-chilis sauce was 40 s. In propidium iodide uptake study, M + CL was found to cause most severe damage to cell membrane (758.5 of PI value for E. coli O157:H7) while M + CU and M + CN had little impact. In DiBAC4(3) test, CL resulted in the largest value (2.09 for E. coli O157:H7). These observations highlight that CL induces synergistic effects as it caused severe membrane damage along with destruction of membrane potential. The combined treatment did not show any significant difference in quality change compared to untreated hot-chili sauce (p > 0.05). The result indicates the potential application of CL and M combination for hot-chili sauce processes to ensure microbiological safety with acceptable quality.

Inactivation of Bacillus cereus endospores on black pepper by pulsed superheated steam system.

In this study, a superheated steam (SHS) system was constructed to inactivate Bacillus cereus endospores on the surface of black pepper, and continuous and pulsed treatment was applied to compare sporicidal effects. Additionally, inactivation mechanisms were analyzed to investigate the differences between pulsed and continuous SHS treatments. SHS at 250 °C and 300 °C for 1 min achieved more than a 3 log reduction, whereas SHS at 200 °C for 1 min achieved less than 2 log reduction in the number of endospores. In addition, higher microbicidal effects were confirmed with pulsed SHS treatment with a shorter duty ratio. To elucidate the inactivation mechanisms, inner membrane damage (dipicolinic acid release), intracellular enzyme activities, and DNA integrity were measured after 300 °C SHS pulsed or continuous treatments. After pulsed SHS treatment for up to 20 s, intracellular enzymes were inactivated more rapidly than after continuous treatment, and more DPA was released after 40 s of treatment, indicating that enzyme inactivation occurred prior to inner membrane damage, and pulsed treatment accelerated this mode of action. DNA integrity was significantly lower after 60 s of pulsed or continuous treatment; however, there was no difference in between pulsed and continuous treatments. Our results provide fundamental insights for the sterilization of black pepper by SHS treatment in food industries.

Inactivation of Listeria monocytogenes through the synergistic interaction between plasma-activated water and organic acid.

This study observed that when plasma-activated water (PAW) was combined with organic acid, it showed a synergistic inactivation effect on Listeria monocytogenes, which is highly resistant to PAW. When comparing various organic acids, lactic acid (LA) showed the greatest synergistic effect, followed by malic acid (MA), citric acid (CA), and acetic acid (AA), whereas propionic acid (PA) did not show a synergistic effect. Organic acid lowered the activity of ROS defense enzymes (catalase, superoxide dismutase) by reducing intracellular pH (pHi), which induced the increase in the accumulation of ROS of PAW within the cell. In the end, the synergistic inactivation effect appeared as the increased occurrence of oxidative damage when organic acid was combined as a series of preceding causes. In this case, LA with the greatest ability to lower the pH induced the greatest synergistic effect, suggesting that LA is the best candidate to be combined with PAW. As a result of observing changes in inactivation activity for L. monocytogenes of PAW combined with 1.0% LA while storing at - 80, -20, 4, 25, & 37 °C for 30 days, respectively, it was confirmed that the lower the temperature, the lower the activity loss during the storage period, and that it had an activity of 3.72 log reduction based on 10 min treatment when stored at - 80 °C for 30 days. Application of PAW combined with 1.0% LA stored at - 80 °C for 30 days to mackerel inoculated with L. monocytogenes in ice form resulted in a decrease of 4.53 log after 120 min treatment, without changing the quality of mackerel. These results suggest that combining LA with PAW can be an effective control strategy for L. monocytogenes with high resistance to PAW, and can be effectively utilized, even in ice form.