ultraviolet-C Treatment Research Articles

Effect of UV-C Treatment on the Quality of Fresh-Cut Potatoes Obtained from Tubers of Different Ages

The physico-chemical properties of potato tubers change with age, which can affect not only the quality of the tubers but also the quality and shelf-life of fresh-cut potatoes (FCP) produced from older tubers. One of the methods that has proven useful for extending the shelf-life of some foods is ultraviolet-C (UV-C) irradiation. This study investigated whether UV-C irradiation can mitigate the negative effects of tuber age. FCP from tubers after storage (1 and 9 months), vacuum-packaged, were irradiated with UV-C (2.70 kJ m−2) and stored (6 °C/15 days). The total aerobic mesophilic bacteria count (TAMBC), total and soluble solids content, pH, firmness, color, chlorogenic acid, reducing sugars, sensory properties of raw FCP and subsequently boiled and fried FCP, and acrylamide content in fried FCP were monitored. UV-C irradiation of FCP does not affect all parameters equally for both tuber ages, but was generally effective in reducing TAMBC, and UV-C-treated samples reached a shelf-life of 15 days. UV-C irradiation improved the sensory properties of raw and thermally processed FCP at both ages. UV-C irradiation caused an increase in acrylamide content in fried FCP, regardless of. the tubers age, but all samples were safe in this respect.

Destructive effect of UV-C light radiation on lettuce growth: risk assessment of long time exposure

Ultraviolet C (UV-C) light technology employs a particular wavelength within the ultraviolet spectrum to deactivate microorganisms, utilizing radiation as its method. UV-C light possesses germicidal properties, effectively disrupting the DNA of microorganisms such as bacteria, viruses and various pathogens, thereby impeding their ability to replicate and induce illness. Additionally, UV-C could enhance the production of phytochemicals and prevent contamination in agricultural applications. However, overexposure to UV-C can cause safety issues, especially for operators handling its utilization in germicidal or sterilization applications. This study investigated the destructive effects of UV-C light on the morphology and chlorophyll content of lettuces exposed to various durations, aiming to assess the risks associated with prolonged exposure. The results showed that prolonged UV-C exposure affects morphological and chlorophyll content changes. The most damaging effect on lettuce morphology and chlorophyll content was found in the 2 h of UV-C exposure treatment. In the 2 h of UV-C exposure treatment, lettuce length was reduced from 6.01 ± 0.80 cm on day 2 to 5.55 ± 0.78 cm on day 3. The lowest fresh weight of lettuce was also found at 2 h of UV-C exposure treatment (4.32 ± 0.94 gr). In addition, the lowest total lettuce stomata aperture was found in 2 h of UV-C treatment (41 units). Furthermore, on day 4, after 2 h of UV-C exposure treatments, the chlorophyll a, chlorophyll b and total chlorophyll content in lettuces were found to be 1.59 ± 0.02 mg g−1 FW, 0.93 ± 0.02 mg g−1 FW and 2.52 ± 0.04 mg g−1 FW, respectively. Therefore, the most destructive effect of UV-C was found during 2 h of UV-C exposure treatment. These findings indicate the dangers of long-term UV-C exposure to lettuce. Practically, this could also have a negative impact on humans. The knowledge gleaned from these findings is useful for safety issues in the industrial application of UV-C.

Surface Cleaning with a Microfiber Cloth and Water followed by Ultraviolet-C Light Exposure Achieves Non-Inferior Disinfection of a Pathogenic Staphylococcus aureus Strain versus Use of Germicidal Wipes.

We hypothesized that ultraviolet-C (UV-C) irradiation (Surfacide, Waukesha, WI) following use of microfiber cloths (Sanny Shop LLC, Longmont, CO) soaked in waterwould be noninferior to surface disinfection wipes containing a quaternary ammonium compound and alcohol (PDI Healthcare, Woodcliff Lake, NJ)for the pathogenic Staphylococcus aureus (S. aureus) sequence type 5 (ST5). This was a randomized laboratory study of disinfection approaches for S. aureusST5. A total of 270 polycarbonate slides loaded with ST5 were prepared for the standard surface disinfection group (N=18) and water-soaked microfiber cloths and UV-C treatment group (N=144), along with positive and negative microbiological controls. All 18 samples of S. aureus ST5 bacteria treated with standard chemical wipes showed complete disinfection (colony forming units (CFU) = 0). All 144 treatments with water-soaked microfiber wipes followed by UV-C exposure showed complete disinfection (CFU =0) regardless of soiling, height from the floor, or orientation to the emitters. The upper 95% exact one-sided confidence limit for any CFU >0 was 2.1%. These data affirm our hypothesis that surface wiping with a damp cloth followed by triangular UV-C irradiation delivery is noninferior to surface disinfection for S. aureusST5 using germicidal wipes, even when UV-C is compromised by height from the floor and orientation to the emitters and surface disinfection is targeted. Removing bioburden with chemical-free microfiber cloths followed by triangular UV-C delivery is a noninferior strategy to targeted surface disinfection with chemical disinfecting wipes for the pathogenicS. aureusST5 strain in the laboratory setting.

Ultraviolet C radiation on polypropylene: A potential way to reduce plastic pollution

This study investigates the application of ultraviolet C (UVC) radiation to extend the lifetime of healthcare items containing polypropylene (PP), particularly personal protective equipment (PPE). The main objectives involve assessing possible PP damage from UVC exposure and detecting UVC treatment within PP samples. FTIR spectroscopy and Raman spectroscopy reveal slight degradation in UVC-irradiated PP samples, demonstrating resilience post-treatment. Investigations using commercial thermoluminescence dosimeters (TLD-100, TLD-200, TLD-400 and GR-200) positioned under varying thicknesses of PP (0.20 and 0.80 mm) identify TLD-100 as a promising UVC detector. Conversely, TLD-200 and TLD-400 do not prove to be effective detectors, exhibiting similar behavior to the dosimeters without a plastic sample. And GR-200 does not possess the capability to differentiate between ionizing and non-ionizing components of UVC radiation. This research emphasizes the role of UVC to prolong the lifetime of healthcare items containing PP, thus aiding in efforts to reduce plastic pollution.

Grapefruit essential oil combined with UV-C treatment: A technology to improve the microbial safety of fresh produce

This study investigated the use of grapefruit essential oil (GEO) in combination with ultraviolet-C (UV-C) to improve the microbial safety of fresh produce. The potent components of GEO, including d-Limonene, tramadol, Ocimene, 1-(benzyloxy) urea, and linalyl propionate, were identified. The combined treatment of 0.8% (w/v) GEO followed by UV-C at 100 mJ/cm2 resulted in reduced levels of E. coli O157:H7 and HuNoV surrogates (MNV-1 and TV) on cherry tomatoes, lettuce, and blueberries, with observed reductions of 1.92–3.96 log10 CFU or PFU/g, exceeding the reductions achieved with either treatment alone. This approach also reduced the time to complete inactivation of the microbial population from 10 to 8 min. TEM showed that GEO induced denaturation of bacterial membranes and viral capsid proteins, which enhanced the UV-C antimicrobial effect. Furthermore, the microbial reductions achieved by this approach remained effective during 7-day storage at 4 °C, and subsequent sensory evaluations indicated no adverse effects on the quality of the fresh produce. This approach effectively improves the safety of fresh produce while maintaining quality. Industrial relevanceThis study shows that the combination of grapefruit essential oil (GEO) with UV-C significantly reduced E. coli O157:H7 and Norovirus surrogates on cherry tomatoes, lettuce and blueberries, shortened the time to complete inactivation of the microbial population and maintained efficacy during storage without compromising produce quality. This method demonstrated the potential to control foodborne pathogens while maintaining the quality of fresh produce.

Enhancing Raw Bovine Milk Quality using Ultraviolet-C (UV-C) Irradiation: A Microbial and Lipid Peroxidation Study.

This study investigated the efficacy of ultraviolet-C (UV-C) irradiation in enhancing the quality of raw bovine milk by targeting microbial populations and lipid peroxidation, both of which are key factors in milk spoilage. We categorized the raw milk samples into three groups based on initial bacterial load: low (<3 Log 10 CFU/mL), medium (3-4 Log 10 CFU/mL), and high (>4 Log 10 CFU/mL). Using a 144 W thin-film UV-C reactor, we treated the milk with a flow rate of 3 L/min. We measured the bacterial count including standard plate count, coliform count, coagulase-negative staphylococci count, and lactic acid bacteria count and lipid peroxidation (via thiobarbituric acid reactive substances assay) pre- and post-treatment. Our results show that UV-C treatment significantly reduced bacterial counts, with the most notable reductions observed in high and medium initial load samples (>4 and 3-4 Log 10 CFU/mL, respectively). The treatment was particularly effective against coliforms, showing higher reduction efficiency compared to coagulase-negative staphylococci and lactic acid bacteria. Notably, lipid peroxidation in UV-C treated milk was significantly lower than in pasteurized or untreated milk, even after 72 hours. These findings demonstrate the potential of UV-C irradiation as a pre-treatment method for raw milk, offering substantial reduction in microbial content and prevention of lipid peroxidation, thereby enhancing milk quality.

Improved postharvest quality attributes of sweet and sour cherry by using low pressure UVC versus light-emitting diodes (LEDs)

The aim of this study was to evaluate the effects of LPUVC253.7 nm and LEDs405.5 nm light on sweet and sour cherries, to assess the potential of post-harvest illumination for fruit shelf-life and quality extension. Fresh cherries were treated at several doses (up to 1.56 kJ m−2) in a lab design chamber. Microbiological parameters, total phenolic content, antioxidant activity, and quality properties such as weight loss, color, pH, and total soluble solids content, were assessed before and after illumination and during storage time up to 24 days at 4 and 25 °C. Studies on inactivation of natural fruit microbiota and artificially inoculated potential spoilage bacteria Pseudomonas syringae and Aureobasidium pullulans were performed. A maximum reduction of 1.89 and 1.66 log on total aerobic mesophilic bacteria and total mold and yeasts was obtained after light illumination at 253.7 nm on spiked cherry fruits. Regarding fruit quality properties, both light (LPUVC253.7 nm and LEDs405.5 nm) illumination caused no change (p > 0.05) in quality parameters compared with non-treated fruits.Industrial relevance: There is an increasing global demand from consumers for agricultural products high nutritional quality with no or minimal chemical preservatives. Postharvest physical ultraviolet-C (UVC) treatment before or during cold storage can inactivate microbial contaminants, alleviate low-temperature damage, reduce postharvest decay, and extend shelf life of fruits while improving chemical safety. The present study indicated that post-harvest LPUVC and LEDs illumination of cherries can be used as a clean and environmental forthcoming process to extend the shelf-life of fruits with highly preserved quality.

UV-C LED-induced cyclobutane pyrimidine dimer formation, lesion repair and mutagenesis in the biofilm-forming diatom, Navicula incerta

The use of ultraviolet-C (UV-C) irradiation in marine biofouling control is a relatively new and potentially disruptive technology. This study examined effects of UV-C exposure on the biofilm-forming diatom, Navicula incerta. UV-C-induced mutations were identified via Illumina HiSeq. A de novo genome was assembled from control sequences and reads from UV-C-exposed treatments were mapped to this genome, with a quantitative estimate of mutagenesis then derived from the frequency of single nucleotide polymorphisms. UV-C exposure increased cyclobutane pyrimidine dimer (CPD) abundance with a direct correlation between lesion formation and fluency. Cellular repair mechanisms gradually reduced CPDs over time, with the highest UV-C fluence treatments having the fastest repair rates. Mutation abundances were, however, negatively correlated with CPD abundance suggesting that UV-C exposure may influence lesion repair. The threshold fluence for CPD formation exceeding CPD repair was >1.27 J cm−2. Fluences >2.54 J cm−2 were predicted to inhibit repair mechanisms. While UV-C holds considerable promise for marine antifouling, diatoms are just one, albeit an important, component of marine biofouling communities. Determining fluence thresholds for other representative taxa, highlighting the most resistant, would allow UV-C treatments to be specifically tuned to target biofouling organisms, whilst limiting environmental effects and the power requirement.

Radiant Reinforcement: Enhancing Composite Polymer Magnet Materials Mechanical Properties with UVC Medical Disinfection.

Magnetic polymer composites have recently attracted considerable interest, primarily because of their promising applications, especially in the biomedical industry. The aim of this study is to investigate the impact of ultraviolet C (UVC) irradiation as a disinfection method on the mechanical characteristics of composite polymer magnets. Tensile and compression tests were conducted following the standards set by ASTM D3039 and ASTM D3410, respectively. In addition, energy dispersive spectroscopy (EDS) was used to determine the effect of the disinfection method on the amount of carbon, oxygen, and iron within the surface of the composite polymer magnet material. The UVC's irradiation impact was statistically assessed by a t-test. The results of the tensile tests demonstrated a significant increase in the transition force, measuring 0.41 kN and 0.58 kN before and after UVC exposure, respectively. Similarly, the outcomes of the compression tests showed a notable increase in yield force, registering 4.9 kN and 6 kN before and after UVC treatment. This suggests that the composite magnetic material has gained a higher capacity to withstand compressive loads than tensile loads. Finally, the EDS analysis revealed the carbon mass percentage was 71.69% prior to UVC radiation exposure, with it increasing to 78.56%, following exposure. This suggests that the composite material exhibited improved hardness. These findings highlight that UVC irradiation has a beneficial impact on both the mechanical and chemical properties of the composite magnet material, which support its use as a disinfection method in clinical settings.

Effect of continuous instant pressure drop treatment on the rheological properties and volatile flavor compounds of whole highland barley flour

Continuous instant pressure drop (CIPD) treatment effectively reduces microbial contamination in whole highland barley flour (WHBF). Base on it, this study further investigated its effects on flour properties (especially rheological properties) and volatile compounds (VOCs) profile of WHBF, and compared it with that of ultraviolet-C (UV-C), ozone and hot air (HA) treatments. The results showed that the damaged starch content (6.0%) of CIPD-treated WHBF was increased, leading to a rough surface and partial aggregation of starch particle, thereby increasing the particle size (18.06 μm of D10, 261.46 μm of D50 and 534.44 μm of D90). Besides, CIPD treatment exerted a positive influence on the structure and rheological properties of WHBF, including an elevation in pasting temperature and viscosity. Notably, CIPD-treated WHBF exhibited higher storage modulus and loss modulus compared to the other three groups of sterilization treatments, contributing to the formulation of a better-defined and stable gel strength (tan δ = 0.38). UV-C and ozone, as cold sterilization techniques, also induced alterations in specific characteristics of WHBF. UV-C treatment led to changes in WHBF's crystallinity, while ozone treatment caused modifications in the secondary protein structure of WHBF. A total of 68 VOCs were identified in raw WHBF (including 3 acids, 19 alcohols, 25 aldehydes, 1 alkene, 8 esters, 2 ethers, 3 furans, and 7 ketones). The maximum flavor-contributing VOC in CIPD-treated WHBF remained dimethyl sulfide monomer (cabbage aroma), consistent with the raw WHBF. Conversely, in HA-treated WHBF, the maximum flavor-contributing VOC shifted to 2-furanmethanethiol monomer (roasted coffee aroma), altering the initial flavor presentation. These findings will provide strong support for the application of CIPD technology in the powdery foods industry.

Ultraviolet-C-Based Mobile Phone Sanitisation for Global Public Health and Infection Control.

Mobile phones act as fomites that pose a global public health risk of disseminating microorganisms, including highly pathogenic strains possessing antimicrobial resistances. The use of ultraviolet-C (UV-C) to sanitise mobile phones presents an alternative means to complement basic hand hygiene to prevent the cross-contamination and dissemination of microorganisms between hands and mobile phones. This study aimed to evaluate the germicidal efficacy of the Glissner CleanPhone UV-C phone sanitiser (Glissner) device. Two experimental trials were performed for the evaluation of the CleanPhone (Glissner). The first was a controlled trial, where the germicidal efficacy of the CleanPhone was evaluated against six different microorganism species that were inoculated onto mobile phones. The second was a field trial evaluating the germicidal efficacy of the CleanPhone on 100 volunteer mobile phones. Efficacy was determined based on colony counts of microorganisms on Columbia sheep blood agar before and after UV-C treatment. In the controlled trial, reduction in growth was observed for all microorganisms after UV-C treatment with ST131 Escherichia coli showing the highest growth reduction at 4 log10 CFU/mL followed by C. albicans and ATCC E. coli at 3 log10 CFU/mL. An overall reduction in microorganism growth after UV-C treatment was also observed for the field trial, with an average growth reduction of 84.4% and 93.6% in colony counts at 24 h and 48 h post-incubation, respectively. The findings demonstrated the capability of the CleanPhone (Glissner) to rapidly sanitise mobile phones, thereby providing a means to reduce the potential dissemination of microorganisms, including highly pathogenic strains with antimicrobial resistance.

Reducing Powdery Mildew in High-tunnel Tomato Production in Oregon with Ultra Violet-C Lighting

Widespread outbreaks of tomato powdery mildew (Leveillula taurica and Oidium neolycopersici) are problematic in fresh market tomato (Solanum lycopersicum) crops in western Oregon, USA. In western Oregon, fresh market tomatoes are frequently grown in greenhouses or high tunnels where conditions can promote diseases such as powdery mildew. Heightened concerns about worker safety limit the pesticides available for use in enclosed systems. We studied the efficacy of ultraviolet-C (UV-C) light applications under high-tunnel conditions compared with a standard fungicide program. Plants treated with UV-C had zero incidence of powdery mildew on all sample dates in the first trial. In trial 2, disease incidence was lower on UV-C treated plants than both grower standard and nontreated control early in the study while disease severity remained lower in UV-C than nontreated control and similar to grower standard treatment. Additional research is needed to optimize UV-C treatment intervals to minimize negative effects on plant growth and maximize powdery mildew control.

1-Methylcyclopropene and UV-C Treatment Effect on Storage Quality and Antioxidant Activity of 'Xiaobai' Apricot Fruit.

The 'Xiaobai' apricot fruit is rich in nutrients and is harvested in summer, but the high temperature limits its storage period. To promote commercial quality and extend shelf life, we investigated the effectiveness of Ultraviolet C (UV-C) combined with 1-methylcyclopropene (1-MCP) treatment on 'Xiaobai' apricot fruit stored at 4 ± 0.5 °C for 35 days. The results revealed that the combination treatment of 1-MCP and UV-C performed better than either UV-C or 1-MCP alone in fruit quality preservation. The combination treatment could delay the increase in weight loss, ethylene production, and respiration rate; retain the level of soluble solid content, firmness, titratable acid, and ascorbic acid content; promote the total phenolics and flavonoids accumulation; improve antioxidant enzyme activity and relative gene expression, and DPPH scavenging ability; and reduce MDA, H2O2, O2.- production. The combined treatment improved the quality of apricot fruit by delaying ripening and increasing antioxidant capacity. Therefore, combining UV-C and 1-MCP treatment may be an effective way to improve the post-harvest quality and extend the storage period of the 'Xiaobai' apricot fruit, which may provide insights into the preservation of 'Xiaobai' apricot fruit.

Assessment of the cytoprotective effect of Vitex negundo ethanol extract on ultraviolet-C induced oxidative stress in human corneal epithelial cells

Human cornea is more susceptible to ultraviolet-C radiation during occupational injuries, and artificial sources such as welding arc, germicidal lamps, etc and continuous exposure leads to various ocular surface diseases. The cytoprotective role of plant extracts against oxidative damages induced by UVC irradiation is less studied in corneal epithelial cells.To investigate the protective of Vitex negundo ethanol (VNE) extract on ultraviolet-C (UVC) radiation induced oxidative stress in human corneal epithelial (HCE) cells. UVC radiation of wavelength (254 nm) and energy density 200 J/m2 was used to irradiate HCE, and cell viability was assessed by trypan blue assay. The reactive oxygen species (ROS) production was analyzed using 2’,7’-dichlorodihydrofluorescein diacetate (DCF-DA) method. Cell cycle analysis was done to check the effects of UVC irradiation and VN extract on the cell growth cycle of HCE cells. The mitochondrial membrane potential (Δψm) was checked by 5,5′,6,6'-tetrachloro-1,1',3,3′-tetrathylbenzimidazol carbocyanine iodide (JC-1) staining method. The HCE cell viability was diminished after UVC irradiation which was improved after VNE extract treatment. The morphological analysis revealed that UVC irradiated HCE cells lost membrane permeability which led to cell death thereby having decreased confluency. VNE extract effectively decreased UVC- induced ROS production and reduced the G1 phase arrest of the cell cycle analysis in HCE cells. The changes or loss in Δψm after UVC treatment was restored after VNE extract treated cells.VNE extract showed strong protective effect against UVC light induced injury in HCE cells which suggests the therapeutic use of these extracts in ocular surface injuries.

A Novel High-Energy Vacuum Ultraviolet Light Photofunctionalization Approach for Decomposing Organic Molecules around Titanium.

Titanium undergoes biological aging, represented by increased hydrophobicity and surface accumulation of organic molecules over time, which compromises the osseointegration of dental and orthopedic implants. Here, we evaluated the efficacy of a novel UV light source, 172 nm wavelength vacuum UV (VUV), in decomposing organic molecules around titanium. Methylene blue solution used as a model organic molecule placed in a quartz ampoule with and without titanium specimens was treated with four different UV light sources: (i) ultraviolet C (UVC), (ii) high-energy UVC (HUVC), (iii) proprietary UV (PUV), and (iv) VUV. After one minute of treatment, VUV decomposed over 90% of methylene blue, while there was 3-, 3-, and 8-fold more methylene blue after the HUVC, PUV, and UVC treatments, respectively. In dose-dependency experiments, maximal methylene blue decomposition occurred after one minute of VUV treatment and after 20-30 min of UVC treatment. Rapid and effective VUV-mediated organic decomposition was not influenced by the surface topography of titanium or its alloy and even occurred in the absence of titanium, indicating only a minimal photocatalytic contribution of titanium dioxide to organic decomposition. VUV-mediated but not other light source-mediated methylene blue decomposition was proportional to its concentration. Plastic tubes significantly reduced methylene blue decomposition for all light sources. These results suggest that VUV, in synergy with quartz ampoules, mediates rapid and effective organic decomposition compared with other UV sources. This proof-of-concept study paves the way for rapid and effective VUV-powered photofunctionalization of titanium to overcome biological aging.

Degradation of Alternaria mycotoxins by UV-C irradiation: Effect of selected process and exposure to food components

Alternariol (AOH) and alternariol monomethyl ether (AME) are two Alternaria mycotoxins with high occurrence rates in food systems. This study aimed to investigate the photodegradation of AOH and AME by ultraviolet-C (UV-C) irradiation. The effect of UV-C intensity, pH, treatment time, solvents and the exposure of food components were evaluated. After treated by UV-C irradiation at 3500 μW/cm2 for 90 min, AOH samples in methanol, aqueous solution and solid state were degraded by 89.1%, 72.9% and 53.2%, respectively, while the degradation percentages of AME were 86.6%, 50.1% and 11.1%, respectively. Increasing irradiation intensity and prolonging irradiation time could significantly facilitate the degradation of AOH and AME. An alkaline environment (pH = 11) was more conducive to the degradation of toxins. In addition, 2.5 mg mL−1 citric acid or malic acid increased the photodegradation of AOH and AME to 94.6% and 95.3%, 93.2% and 70.5%, respectively. However, protein, polyphenols and vitamin C exerted inhibitory effects on the degradation, while 10% glucose or sucrose reduced the photodegradation of AOH and AME to 65.9% and 40.3%. UV-C treatment could effectively reduce the content of AOH and AME, with the highest efficiency achieved in methanol and alkaline environment. By contrast, UV-C irradiation is more effective in degrading toxins in some liquid foods rich in organic acids but lacking in protein. The utilization of UV-C radiation appears to be a potentially useful approach for decreasing the underlying risk of Alternaria mycotoxin contamination in foods.

Effect of ultraviolet‐C radiation and pasteurization on quality and shelf life of refrigerated tender coconut water fortified with edible bird’s nest protein hydrolysate

Physicochemical and microbiological qualities of tender coconut water (TCW) with and without edible bird’s nest protein hydrolysate (EBPH) (TCW-EBPH and TCW, respectively) subjected to ultraviolet-C (UV-C) radiation and pasteurization under various conditions were studied. All TCW-EBPH samples had lower L*-value with higher a* and b*-values, browning index, turbidity, and pH than without EBPH. The sample pasteurized with low temperature long time was not acceptable due to off-color and off-flavor. Shelf life of TCW-EBPH with UV treatment (TCW-EBPH-UV), TCW treated with UV (TCW-UV), and TCW-EBPH pasteurized with high temperature short time (TCW-EBPH-HT) was extended to 9, 12, and 15 days, respectively, based on the microbiological limit. Slight changes in color, browning index, and turbidity were found for TCW during storage. Some changes in volatile compounds were observed for TCW-EBPH-UV and TCW-EBPH-HT after 15 days of storage, while acids were dominant in TCW-EBPH. Therefore, UV-C treatment and pasteurization process were alternative preservation approaches for TCW containing EBPH. Novelty impact statement EBPH has high nutritive value with benefits for the neurological and immunological systems of humans. Thus, fortification of EBPH could be an interesting means to enhance the nutritional values of beverage, particularly TCW. To avoid thermal process with harsh condition, the UV-C radiation and pasteurization under appropriate condition are the potential methods for the production of TCW containing EBPH to avoid off-odor of off-flavor. In addition, the shelf life of TCW could be extended and quality could be maintained.

Effect of Ultraviolet-c (UVc) light and ozone on the survival of Mycobacterium abscessus complex organisms associated with cystic fibrosis.

Members of the Mycobacterium abscessus complex have now emerged as clinically significant respiratory pathogens in people with cystic fibrosis (CF), potentially leading to increased disease severity, antibiotic treatment, and persistence dilemmas. Many of these species are resistant to disinfectants and biocides commonly used to clean and disinfect the hospital environment, thus necessitating the need to examine innovative ways to eliminate these organisms from such environments. It was, therefore, the aim of this study to examine the individual effect of ultraviolet-c (UVc) light (λ = 254 nm) and ozone (O3) on the growth of the M. abscessus complex organisms, as well as on seven other clinically significant CF pathogens, including Achromobacter spp., Burkholderia gladioli, Burkholderia cenocepacia, Burkholderia multivorans, Pseudomonas aeruginosa, Staphylococcus aureus, and Stenotrophomonas maltophilia. Bacterial isolates (n = 46), including M. abscessus complex (n = 6) (M. abscessus subsp abscessus [n = 2], M. abscessus subsp. bolletii [n = 2], M. abscessus subsp. massiliense [n = 2]), and other CF pathogens (n = 40) including Achromobacter spp., B. gladioli, B. cenocepacia, B. multivorans, P. aeruginosa, S. aureus, and S. maltophilia, were exposed for 1 h to UVc light (254 nm), as well as to ozone (O3; 26 ppm). UVc light inactivated all M. abscessus complex organisms (n = 6), as well as the 40 isolates from the other genera and species. No bacterial species tested was able to survive the UVc treatment. O3 was unable to inactivate all isolates of M. abscessus subsp. abscessus (n = 2), M. abscessus subsp. bolletii (n = 2), and one isolate of M. abscessus subsp. massiliense, but killed one strain of M. abscessus subsp. massiliense. Overall, O3 inactivated only 20% of total isolates, allowing the posttreatment growth of the remaining 80% of isolates. There was no difference in the growth dynamic of P. aeruginosa from the environmental waters which had received O3 treatment and the control (untreated with O3). Bacterial growth, while occurring post-O3 treatment, was not as prolific in all remaining organisms, as in the untreated controls, demonstrating some but limited antibacterial effect. From the data presented by this study, UVc light at 254 nm was effective at eliminating all organisms examined, including members of the M. abscessus complex. Given the refractory nature of these organisms against conventional wet chemical disinfection, UVc potentially offers a physical method to control and eliminate the survival of these organisms on health-care surfaces and fomites. For many CF species examined in this study, these data represent the first reports of the organisms susceptibility to UVc light. Further work is now required to establish time/distance parameters incorporated into newly designed innovative devices, to allow disinfection protocols to be optimized, and delivered to exploit this vulnerability with these nontuberculous mycobacterial organisms, as well as with the other bacterial species examined.

Single Ultraviolet-C light treatment of early stage marine biofouling delays subsequent community development

Past studies of Ultraviolet-C (UV-C) radiation as a marine antifoulant have focused on repeated doses. However, single or very low frequency exposures of UV-C could create more plausible applications for certain marine structures. The objective of the study reported here was to apply a single treatment of UV-C radiation to an early stage marine biofouling community to observe subsequent effects on biofouling development. Biofouling formed over a 2-week field immersion received UV-C treatments of 0 (control), 4, 20, or 120 min, and subsequent progression was then monitored weekly for 16 weeks. Analysis of acute effects and later macrofouling development suggested direct toxicity of UV-C illumination to invertebrate recruits caused reduction of subsequent biofouling (compared to controls) that persisted for up to 16 weeks following the longest UV-C treatment. Thus, UV-C treatments spaced by days or even weeks could be an option for some applications of UV-C radiation as an antifoulant.

Improvement in Osseointegration of Titanium Dental Implants After Exposure to Ultraviolet-C Light for Varied Durations: An Experimental Study in Beagle Dogs

Ultraviolet-mediated photofunctionalization is a valid technology for enhancing the osseointegration of titanium implants. However, there is no consensus on the effective exposure time to ultraviolet light. The objective of this study was to evaluate the effect of different exposure times of ultraviolet-C (UVC) light on aged titanium implants and explore the optimal treatment duration of UVC photofunctionalization for osseointegration in an animal model. Eight male beagle dogs (n=48) were divided into a control group (n=12) and 3 experimental groups (n=12/12/12) which received 4-week-old implants without UVC treatment (C) or treated with UVC for 1/6hour, 1/2hour, and 1hour (UVC-1/6hour, UVC-1/2hour, UVC-1hour) immediately before placement. All the implants were placed 12weeks after mandibular premolars extraction. Four dogs were euthanized after 4 and 12weeks of healing, respectively. The marginal bone level and implant stability quotient were measured at implant placement and after sacrifice. Subsequently, micro-CT and histomorphometric analyses were performed following block harvesting. No significant difference in marginal bone loss between the UVC-untreated and UVC-treated groups was found at 4 or 12weeks. At 4weeks, significantly higher BV/TV and bone-implant contact were observed in the UVC groups than in the C group, irrespective of the UVC-photofunctionalization duration (BV/TV: UVC-1/6hour 0.48±0.11, UVC-1/2hour 0.50±0.06, and UVC-1hour 0.47±0.08, C 0.34±0.04; bone-implant contact : UVC-1/6hour 84.30±5.02%, UVC-1/2hour 85.82±5.05%, and UVC-1hour 84.98±3.86%, C 71.69±3.52%. P<.05), whereas, no significant difference was observed among the UVC groups. At 12weeks, there were no significant differences between the C group and UVC groups. After 4 and 12weeks of healing, no significant difference in implant stability quotient values was observed between the C group and UVC groups. UVC photofunctionalization improved the early osseointegration of aged titanium implants. However, the effect was not dependent on the UVC-light duration within the range from 1/6hour to 1hour.