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Journal of Food Science Feb 2024Wheat kernels harbor a diverse microflora that can negatively affect the suitability of the grains for further processing. To reduce surface microflora, a kernel...
Wheat kernels harbor a diverse microflora that can negatively affect the suitability of the grains for further processing. To reduce surface microflora, a kernel disinfection method is required that does not affect grain functionality. Three different versions of gas phase hydroxyl-radical processes were compared with the common method for grain disinfection, that is, a bleach treatment. The gas phase hydroxyl-radicals are generated by the UV-C mediated degradation of hydrogen peroxide and/or ozone in a near water-free process. It was found that treating kernels with a bleach solution could reduce total aerobic count (TAC) and fungal count to below the level of enumeration. In comparison, the gas phase hydroxyl-radical treatment, that is, H O -UV-ozone treatment, could support a 1.3 log count reduction (LCR) in TAC and a 1.1 LCR in fungal count. The microbial load reduction for the wholemeal samples was less pronounced as endophytic microorganisms were less affected by all treatments, hinting at a limited penetration depth of the treatments. Despite reducing the microbial load on the kernel surface through the bleach and H O -UV-ozone treatments, none of these treatments resulted in a reduced microbial count on grains that underwent sprouting after the treatments. No negative effect on germination power or development of the seedling was observed for any of the treatments. The gluten aggregation behavior and xylanase activity of the wholemeal also remained unchanged after the gas phase hydroxyl-radical treatments. Our findings suggest that UV-H O -ozone treatment shows promise for dry-kernel disinfection, but further optimization of the processing parameters is required.
Topics: Disinfection; Triticum; Hydroxyl Radical; Anti-Infective Agents; Ozone; Ultraviolet Rays
PubMed: 38161277
DOI: 10.1111/1750-3841.16883 -
Environmental Science & Technology Jan 2024Ozonation is universally used during water treatment but can form hazardous brominated disinfection byproducts (Br-DBPs). While sunlight exposure is advised to reduce...
Ozonation is universally used during water treatment but can form hazardous brominated disinfection byproducts (Br-DBPs). While sunlight exposure is advised to reduce the risk of Br-DBPs, their phototransformation pathways remain insufficiently understood. Here, sunlight irradiation was found to reduce adsorbable organic bromine by 63%. Applying high-resolution mass spectrometry, the study investigated transformations of dissolved organic matter in sunlit-ozonated reclaimed water, revealing the number and abundance of assigned formulas decreased after irradiation. The Br-DBPs with O/C < 0.6 and MW > 400 Da were decreased or removed after irradiation, with the majority being CHOBr compounds. The peak intensity reduction ratio of CHOBr compounds correlated positively with double bound equivalent minus oxygen ratios but negatively with O/C, suggesting that photo-susceptible CHOBr compounds were highly unsaturated. Mass difference analysis revealed that the photodegradation pathways were mainly oxidation aligned with debromination. Three typical CHOBr molecular structures were resolved, and their photoproducts were proposed. Toxicity estimates indicated decreased toxicity in these photoproducts compared to their parent compounds, in line with experimentally determined values. Our proposed phototransformation pathways for Br-DBPs enhance our comprehension of their degradation and irradiation-induced toxicity reduction in reclaimed water, further illuminating their transformation under sunlight in widespread environmental scenarios.
Topics: Disinfection; Disinfectants; Halogenation; Water Pollutants, Chemical; Water Purification
PubMed: 38154042
DOI: 10.1021/acs.est.3c06972 -
Water Research Feb 2024Ozone‒chlor(am)ine is a commonly used combination of disinfectants in drinking water treatment. Although there are quite a few studies on the formation of some...
Ozone‒chlor(am)ine is a commonly used combination of disinfectants in drinking water treatment. Although there are quite a few studies on the formation of some individual DBPs in the ozone‒chlor(am)ine disinfection, an overall picture of the DBP formation in the combined disinfection is largely unavailable. In this study, the effects of ozone dose on the formation and speciation of organic brominated disinfection byproducts (DBPs) in subsequent chlorination, chloramination, or chlorination‒chloramination of simulated drinking water were investigated. High-molecular-weight, aliphatic, alicyclic and aromatic brominated DBPs were selectively detected and studied using a powerful precursor ion scan method with ultra performance liquid chromatography/electrospray ionization triple quadrupole mass spectrometry (UPLC/ESI-tqMS). Two groups of unregulated yet relatively toxic DBPs, dihalonitromethanes and dihaloacetaldehydes, were detected by the UPLC/ESI-tqMS for the first time. With increasing ozone dose, the levels of high-molecular-weight (m/z 300-500) and alicyclic and aromatic brominated DBPs generally decreased, the levels of brominated aliphatic acids were slightly affected, and the levels of dihalonitromethanes and dihaloacetaldehydes generally increased in the subsequent disinfection processes. Despite different molecular compositions of the detected DBPs, increasing ozone dose generally shifted the formation of DBPs from chlorinated ones to brominated analogues in the subsequent disinfection processes. This study provided a comprehensive analysis of the impact of ozone dose on the DBP formation and speciation in subsequent chlor(am)ine disinfection.
Topics: Disinfection; Ozone; Drinking Water; Water Pollutants, Chemical; Disinfectants; Water Purification; Halogenation
PubMed: 38142503
DOI: 10.1016/j.watres.2023.121039 -
Food Chemistry May 2024Effects of steam sterilization, gamma-irradiation, UV-irradiation and ozonation on microbial inactivation, pyrrolizidine alkaloid degradation and volatile compound...
Effects of steam sterilization, gamma-irradiation, UV-irradiation and ozonation on microbial inactivation, pyrrolizidine alkaloid degradation and volatile compound profile in oregano were investigated. Steam sterilization and gamma-irradiation were the most effective treatments in inactivating microorganisms. These treatments resulted in 0.87-2.15 log reductions in total aerobic mesophilic bacteria counts and reduced yeast-mold and Enterobacteriaceae counts below the detectable level. Steam sterilization caused increased levels of pyrrolizidine alkaloids (PAs) and decreased levels of their N-oxide forms (PANOs) demonstrating a simultaneous conversion of PANOs into the corresponding PAs. Ozone treatment caused significant decreases in the levels of individual and total PAs/PANOs. After ozone treatment, decreases of 54.4, 53.9, 61.6 and 61.4% were observed in the levels of europine-N-oxide, europine, lasiocarpine-N-oxide and lasiocarpine, respectively. Steam sterilization, UV-irradiation and ozone treatments significantly altered the composition of the volatile compounds of oregano as evidenced by decreased levels of major components and the formation of some new compounds.
Topics: Origanum; Steam; Pyrrolizidine Alkaloids; Oxides; Ozone
PubMed: 38134825
DOI: 10.1016/j.foodchem.2023.138235 -
Nanotechnology Jan 2024Ultraviolet germicidal irradiation (UVGI) and ozone disinfection are crucial methods for mitigating the airborne transmission of pathogenic microorganisms in high-risk...
Ultraviolet germicidal irradiation (UVGI) and ozone disinfection are crucial methods for mitigating the airborne transmission of pathogenic microorganisms in high-risk settings, particularly with the emergence of respiratory viral pathogens such as SARS-CoV-2 and avian influenza viruses. This study quantitatively investigates the influence of UVGI and ozone on the viability ofin bioaerosols, with a particular focus on howviability depends on the size of the bioaerosols, a critical factor that determines deposition patterns within the human respiratory system and the evolution of bioaerosols in indoor environments. This study used a controlled small-scale laboratory chamber wheresuspensions were aerosolized and subjected to varying levels of UVGI and ozone levels throughout the exposure time (2-6 s). The normalized viability ofwas found to be significantly reduced by UVGI (60-240W s cm) as the exposure time increased from 2 to 6 s, and the most substantial reduction ofnormalized viability was observed when UVGI and ozone (65-131 ppb) were used in combination. We also found that UVGI reduced the normalized viability ofin bioaerosols more significantly with smaller sizes (0.25-0.5m) than with larger sizes (0.5-2.5m). However, when combining UVGI and ozone, the normalized viability was higher for smaller particle sizes than for the larger ones. The findings provide insights into the development of effective UVGI disinfection engineering methods to control the spread of pathogenic microorganisms in high-risk environments. By understanding the influence of the viability of microorganisms in various bioaerosol sizes, we can optimize UVGI and ozone techniques to reduce the potential risk of airborne transmission of pathogens.
Topics: Animals; Humans; Disinfection; Ozone; Air Microbiology; Ultraviolet Rays
PubMed: 38086064
DOI: 10.1088/1361-6528/ad14b4 -
Nanomaterials (Basel, Switzerland) Nov 2023Ultraviolet-ozone (UV-O) treatment is a simple but effective technique for surface cleaning, surface sterilization, doping, and oxidation, and is applicable to a wide...
Ultraviolet-ozone (UV-O) treatment is a simple but effective technique for surface cleaning, surface sterilization, doping, and oxidation, and is applicable to a wide range of materials. In this study, we investigated how UV-O treatment affects the optical and electrical properties of molybdenum disulfide (MoS), with and without the presence of a dielectric substrate. We performed detailed photoluminescence (PL) measurements on 1-7 layers of MoS with up to 8 min of UV-O exposure. Density functional theory (DFT) calculations were carried out to provide insight into oxygen-MoS interaction mechanisms. Our results showed that the influence of UV-O treatment on PL depends on whether the substrate is present, as well as the number of layers. Additionally, 4 min of UV-O treatment was found to be optimal to produce p-type MoS, while maintaining above 80% of the PL intensity and the emission wavelength, compared to pristine flakes (intrinsically n-type). UV-O treatment for more than 6 min not only caused a reduction in the electron density but also deteriorated the hole-dominated transport. It is revealed that the substrate plays a critical role in the manipulation of the electrical and optical properties of MoS, which should be considered in future device fabrication and applications.
PubMed: 38063730
DOI: 10.3390/nano13233034 -
The Science of the Total Environment Feb 2024N-nitrosodiethylamine (NDEA), which is the most toxic nitrosamine among the 9 detected species, has been widely detected in drinking water. Amines containing...
N-nitrosodiethylamine (NDEA), which is the most toxic nitrosamine among the 9 detected species, has been widely detected in drinking water. Amines containing diethylamine (DEA) groups in the structure would generate NDEA during the disinfection processes. The aim of this study was to evaluate the feasibility of reducing NDEA formation from a commonly used dithiocarbamate pesticide sodium diethyldithiocarbamate (DEDTC) in subsequent chlorination and chloramination by pre-ozonation. The results demonstrated that NDEA could be generated directly during ozonation, its amounts increased from 0 to 14.34 μg/L with increasing ozone dosages (0-4 mg/L), which was higher than that chlorination (2.68 μg/L) and chloramination (4.91 μg/L) when the initial concentration of DEDTC was 20 μM. Pre-ozonation significantly raised NDEA formation from 2.68 to15.32 μg/L in subsequent chlorination; and that from 4.91 to 9.54 μg/L during subsequent chloramination processes. The addition of •OH scavenger tert-butanol (tBA) increased the production of NDEA from 8.14 to 20.80 μg/L during ozonation, and that from 6.76 to17.98 μg/L in O/HClO process, 8.74 to 17.33 μg/L in O/NHCl process. Except for NO and CO, most of the co-existing substances promoted NDEA generation from DEDTC under disinfection conditions. Based on the results of Gaussian theory calculations, GC/MS and UPLC-Q-TOFMS analysis, the influencing mechanisms of pre-ozonation on NDEA generation in the subsequent disinfection process were proposed. In addition, not only acute/chronic toxicity calculation but also luminescent bacteria test was performed to assess the possibility of pre-ozonation on the risk control of DEDTC. The research results fill a gap in the control of NDEA pollution and help to develop a safer ozone oxidation technology.
Topics: Halogenation; Diethylnitrosamine; Feasibility Studies; Disinfection; Ozone; Water Purification; Water Pollutants, Chemical
PubMed: 38052386
DOI: 10.1016/j.scitotenv.2023.169054 -
Journal of Hazardous Materials Feb 2024Microwave discharge electrodeless lamp (MDEL) is a novel ultraviolet (UV) light source. Synergistic disinfection using UV light emitted by MDEL (MWUV) coupled with ozone...
Microwave discharge electrodeless lamp (MDEL) is a novel ultraviolet (UV) light source. Synergistic disinfection using UV light emitted by MDEL (MWUV) coupled with ozone (O) at an ultra-low dose was investigated. Escherichia coli and Bacillus subtilis were deactivated more effectively by MWUV/O than by either MWUV or O alone. MWUV/O treatment using an O concentration of 0.4 mg/L gave an E. coli inactivation rate of 5.52 log. The photoreactivation degree and rate of E. coli were lower after inactivation by MWUV/O treatment than after MWUV treatment alone. The maximum photoreactivation rates after the MWUV/O and MWUV treatments were 2.90% and 16.08%, respectively. MWUV/O disinfection also inhibited dark resurrection of E. coli and gave a maximum dark resurrection rate of 0.0036%. Electron paramagnetic resonance spectroscopy indicated that more hydroxyl radicals were generated during MWUV/O treatment. Scanning electron microscopy and laser confocal scanning microscopy observations indicated that O played a key role in breaking down the cell structure. MWUV/O treatment gave a good disinfection effect on fecal coliform bacteria in actual domestic wastewater. The results indicated that inactivation of bacteria can be more effectively achieved by MWUV treatment with O.
Topics: Disinfection; Wastewater; Escherichia coli; Microwaves; Ozone; Ultraviolet Rays; Water Purification
PubMed: 37988868
DOI: 10.1016/j.jhazmat.2023.133011 -
International Journal of Molecular... Oct 2023The best form of prevention against human infection through bacteria, viruses, and other parasites is ozone disinfection of wastewater and drinking water as a highly... (Review)
Review
The best form of prevention against human infection through bacteria, viruses, and other parasites is ozone disinfection of wastewater and drinking water as a highly effective, well-known method. Various preclinical studies showed promising results, which are being revisited and reconsidered in times of pandemics and led to interesting results in recent clinical trials and reports, as presented by the example of protective measures against COVID-19 in particularly vulnerable clinical personnel. The application of ozone in the form of the low-dose concept induces its regulation by interference of ozone or its peroxides into the redox equilibrium of the biological system, which finally results in the restoration of the glutathione equilibrium. The antioxidant system is activated, the immune system is modulated, and thus the defense mechanisms are improved. In patients with rheumatoid arthritis, repeated ozone treatments have led to new findings in "immunomodulation" through ozone. The more effective immune response is discussed as the response of innate immune memory and opens interesting aspects for complementary treatment of autoimmune diseases.
Topics: Humans; Ozone; Drinking Water; Disinfection; Wastewater; Oxidation-Reduction
PubMed: 37958730
DOI: 10.3390/ijms242115747 -
Environmental Pollution (Barking, Essex... Jan 2024Evidence linking diminished ovarian reserve, a significant cause of female infertility, and exposure to particulate matter with aerodynamic diameters ≤2.5 μm (PM) or...
Evidence linking diminished ovarian reserve, a significant cause of female infertility, and exposure to particulate matter with aerodynamic diameters ≤2.5 μm (PM) or O exposure remains a critical knowledge gap in female fertility. This study investigated the association between ambient PM, O pollution, and anti-Müllerian hormone (AMH), a sensitive marker of ovarian reserve, in reproductive-aged Chinese women. We enrolled 2212 women with spontaneous menstrual cycles who underwent AMH measurements at a reproductive medicine center between 2018 and 2021. The daily mean concentrations of outdoor PM and O were estimated using a validated spatiotemporal model, followed by matching the participants' residential addresses. Three exposure periods were designed according to AMH expression patterns during follicle development. A generalized linear model was used to investigate changes in AMH associated with air pollution. The results showed a mean AMH level of 3.47 ± 2.61 ng/mL. During the six months from primary to early antral follicle stage (Period 1), each 10 μg/m increase in PM and O exposure was associated with AMH changes of -0.21 (95% confidence interval [CI]: -0.48, 0.06) ng/mL and -0.31 (95% CI: -0.50, -0.12) ng/mL, respectively. Further analyses indicated that the reduced ovarian reserve measured by AMH level was only significantly associated with PM exposure during follicle development from the primary to preantral follicle stage (Period 2) but was significantly associated with O exposure during Periods 1, 2, and 3. These observations were robust in the dual-pollutant model considering co-exposure to PM and O. The results indicated an inverse association between ovarian reserve and ambient O exposure and suggested distinct susceptibility windows for O and PM for reduced ovarian reserve. These findings highlight the need to control ambient air pollution to reduce invisible risks to women's fertility, especially at high O concentrations.
Topics: Female; Humans; Adult; Ozone; Ovarian Reserve; Infertility, Female; Fertility; Particulate Matter
PubMed: 37926414
DOI: 10.1016/j.envpol.2023.122845