Shortwave Ultraviolet Research Articles

Two Short-Wave UV Beryllium Selenites Exhibiting Diverse Optical Properties Stemming from Functional Group Arrangements.

The arrangement of functional groups exerts a crucial role in determining the characteristics of compounds. In this study, we synthesized two novel short-wave ultraviolet (UV) nonlinear optical (NLO) crystals: KBe2(SeO3)2(OH)·H2O and K2Be(SeO3)2. Interestingly, the two compounds show the same SeO3 triangular pyramids and K-O polyhedra. However, the two compounds exhibit distinct beryllium-oxygen anion groups: BeO3(OH) for KBe2(SeO3)2(OH)·H2O and BeO4 for K2Be(SeO3)2. This results in the SeO3 groups within the structure having different orientations, ultimately leading to the two compounds exhibiting completely different optical properties. KBe2(SeO3)2(OH)·H2O displays a large second harmonic generation (SHG) effect equivalent to 2× KH2PO4 (KDP), coupled with a large birefringence of 0.078 at 546 nm. In contrast, the SHG effect and birefringence of K2Be(SeO3)2 are only 0.33× that of KDP and 0.024 at 546 nm, respectively. Structural analyses and theoretical calculations indicate that these pronounced differences in optical properties stem from variations in the arrangement of the SeO3 functional groups. This study not only sheds light on the correlation between crystal structure and optical behavior but also presents a hopeful avenue for the advancement of materials in the short-wave UV spectrum.

Digital Image Correlation at Extreme Temperatures Using Shortwave Ultraviolet (UV-C) Lights and Filters

Digital Image Correlation at Extreme Temperatures Using Shortwave Ultraviolet (UV-C) Lights and Filters

Drastic Microbial Count Reduction in Soy Milk Using Continuous Short-Wave Ultraviolet Treatments in a Tubular Annular Thin Film UV-C Reactor.

Vegetative cells of Listeria monocytogenes and Escherichia coli and spores of Bacillus subtilis and Aspergillus niger were inoculated in soy milk at an initial concentration of ≈5 log CFU/mL. Inoculated and control (non-inoculated) soy milk samples were submitted to three types of treatments using a tubular annular thin film short-wave ultraviolet (UV-C) reactor with 1 mm of layer thickness. Treatments applied depended on the flow rate and the number of entries to the reactor, with UV-C doses ranging from 20 to 160 J/mL. The number of entries into the reactor tube (NET) was established as the most determining parameter for the efficiency of the UV-C treatments. Conidiospores of A. niger were reported as the most resistant, followed by B. subtilis spores, while vegetative cells were the most sensible to UV-C, with Listeria monocytogenes being more sensible than Escherichia coli. Treatments of just 80 J/mL were needed to achieve a 5 log CFU/mL reduction of L. monocytogenes while 160 J/mL was necessary to achieve a similar reduction for A. niger spores.

ASb(SO4)2 (A = Rb, Cs): Two short-wave UV antimony sulfates exhibiting large birefringence

Herein, two antimony sulfates, named RbSb(SO4)2 (1) and CsSb(SO4)2 (2), have been successfully synthesized with the introduction of Sb3+ cation with stereochemically active lone pairs (SCALP) into sulfates by the conventional hydrothermal method. Both two compounds endow short UV absorption edges (281 nm and 278 nm, respectively) and large birefringence ([email protected] nm and [email protected] nm, respectively), which means that they are promising short-wave ultraviolet (UV) optical materials. Interestingly, though both of the two compounds exhibit similar 1D chained structures, and possess the same functional moieties including SbO4 seesaws and SO4 tetrahedral groups, they exhibit significantly opposite macroscopic symmetries, i.e., compound 1 crystallizes in a centrosymmetric (CS) manner (P21/n) and compound 2 in a noncentrosymmetric (NCS) manner (P212121), due to the size of cations [r(Rb+) = 1.56 Å, r(Cs+) = 1.67 Å] affects the orientation of SCALP of the adjacent Sb3+.

Two Mixed-Alkali-Metal Selenates as Short-Wave Ultraviolet Nonlinear-Optical Materials.

Two novel mixed-alkali-metal selenate nonlinear-optical (NLO) crystals, Na3Li(H2O)3(SeO4)2·3H2O (I) and CsLi3(H2O)(SeO4)2 (II), have been successfully synthesized by an aqueous solution evaporation method. Both compounds feature the unique layers constructed of the same functional moieties including SeO4 and LiO4 tetrahedra: [Li(H2O)3(SeO4)2·3H2O]∞3- layers in I and [Li3(H2O)(SeO4)2]∞- layers in II. The titled compounds display wide optical band gaps of 5.62 and 5.66 eV, respectively, according to the UV-vis spectra. Interestingly, they exhibit significantly different second-order nonlinear coefficients (0.34 × KDP and 0.70 × KDP, respectively). Detailed dipole moment calculations manifest that the large disparity can be attributed to the difference in the dipole moment of the crystallographically independent SeO4 and LiO4 groups. This work confirms that alkali-metal selenate system is an excellent candidate for short-wave ultraviolet NLO materials.

Gemological and Luminescence Characteristics of Taaffeites from Mogok, Myanmar

Taaffeite is a rare gem that has been found in different localities such as Tanzania, Sri Lanka, China, and Mogok, Myanmar. In this study, thirty-two taaffeite samples from Mogok, Myanmar, were investigated by conventional gemological testing, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), Raman spectrometry, and fluorescence spectrometry. Through microscopic observations, various types of inclusions were observed in these taaffeites, including irregular inclusions, orange and brown intrusions, black dotted and flake inclusions, healed fissures, tubular inclusions, fingerprint inclusions, and multi-phase inclusions. The Raman spectra demonstrated that the inclusions were mainly calcite, forsterite, celestite, graphite, dolomite, and transparent tubular or columnar inclusions filled with CO2. In previous studies, taaffeite showed inert or chalky fluorescence under long-wave ultraviolet (LWUV) light and inert fluorescence under short-wave ultraviolet (SWUV) light. In this study, the taaffeite samples revealed different fluorescence phenomena under ultraviolet light. Thirty-two taaffeite samples were classified into four categories according to their fluorescence under LWUV: orange-red, pink, green, and blue-white fluorescence. Under SWUV, all samples presented inert to bright pink fluorescence. Two-dimensional fluorescence spectra were obtained through a fluorescence spectrometer. For the samples with orange-red and pink fluorescence under LWUV, two-dimensional fluorescence spectra showed that peaks at 686 nm and 690 nm (in the red region) were strong. For the samples with green and blue-white fluorescence under LWUV, peaks at 439 nm and 464 nm (in the blue region) were strong, peaks at 507–515 nm (in the green region) were relatively weak, and peaks at 686 and 690 nm (in the red region) were very weak. Combined with the data from LA-ICP-MS, it is speculated that Cr3+ was responsible for samples having orange-red and pink fluorescence, that Mn2+ was responsible for samples having green fluorescence, and that Fe inhibited the generation of fluorescence.

Rapid screening of a photochromic Padparadscha-like sapphire using absorption spectroscopy.

The Padparadscha sapphire is attracting increasing interest due to its unique color combination of pink and orange. However, some Padparadscha sapphires exhibit an unstable orange color component; the stone turns from pink to orangey pink after longwave ultraviolet (UV) radiation, and the orange color fades out under a room light or halogen light source. This is of interest and concern since accuracy and consistency are important in colored stone identification services. This study investigates the UV visible (UV-Vis) absorption spectra of photochromic Padparadscha sapphires under illumination of different wavelengths between 250 and 600 nm. Our results show that shortwave UV induces the orange color more effectively than longwave UV, and Vis light near 450 nm reduces the orange color more effectively than a halogen light source. Based on these findings, we developed a prototype UV-Vis absorption spectroscopy device with two fiber-coupled light-emitting diodes at 265 and 455 nm. It can perform rapid screening of photochromic Padparadscha sapphires and has faster color recovery compared to current techniques.

UV Transmission in Natural Waters on Prebiotic Earth.

Ultraviolet (UV) light plays a key role in surficial theories of the origin of life, and numerous studies have focused on constraining the atmospheric transmission of UV radiation on early Earth. However, the UV transmission of the natural waters in which origins-of-life chemistry (prebiotic chemistry) is postulated to have occurred is poorly constrained. In this work, we combine laboratory and literature-derived absorption spectra of potential aqueous-phase prebiotic UV absorbers with literature estimates of their concentrations on early Earth to constrain the prebiotic UV environment in marine and terrestrial natural waters, and we consider the implications for prebiotic chemistry. We find that prebiotic freshwaters were largely transparent in the UV, contrary to assumptions in some models of prebiotic chemistry. Some waters, such as high-salinity waters like carbonate lakes, may be deficient in shortwave (≤220 nm) UV flux. More dramatically, ferrous waters can be strongly UV-shielded, particularly if the Fe2+ forms highly UV-absorbent species such as . Such waters may be compelling venues for UV-averse origin-of-life scenarios but are unfavorable for some UV-dependent prebiotic chemistries. UV light can trigger photochemistry even if attenuated through photochemical transformations of the absorber (e.g., production from halide irradiation), which may have both constructive and destructive effects for prebiotic syntheses. Prebiotic chemistries that invoke waters that contain such absorbers must self-consistently account for the chemical effects of these transformations. The speciation and abundance of Fe2+ in natural waters on early Earth is a major uncertainty and should be prioritized for further investigation, as it played a major role in UV transmission in prebiotic natural waters.

Multi-wave UV-photocatalysis system (UVA+UVC+VUV/Cu-N-TiO2) for efficient inactivation of microorganisms in ballast water

Ballast Water Treatment System (BWTS) is a system designed to remove biological organisms from ballast water. However, the existing BWTSs often have problems in practical applications. In this study, a multiwave ultraviolet (UV)-modified TiO2 photocatalyst biological inactivation system (longwave UV, UVA+shortwave UV, UVC+vacuum UV, VUV/Cu-N-TiO2) for microorganism inactivation in ballast water was established. The results showed that the UVA+UVC+VUV/Cu-N-TiO2 system improved the UV light quantum yield and catalyst activity in the photocatalytic reaction and fully utilized the synergistic inactivation effect of Cu-N-TiO2 photocatalyst+ multiwave UV light (UVA, UVC, and VUV) on microorganisms. Compared with 8 other photocatalytic systems, the logarithmic algae removal rate and logarithmic sterilization rate of the UVA+UVC+VUV/Cu-N-TiO2 system increased to 1.78 log and 5.86 log, respectively. The turbidity of the seawater affected the microorganism inactivation to a certain extent. The humic acid concentration should be controlled below 2 mg L−1 for the UVA+UVC+VUV/Cu-N-TiO2 system to inactivate microalgae more effectively. The multiwave UV photocatalytic system could significantly increase the lipid peroxidation products in microbial cells, rapidly reduce superoxide dismutase (SOD) activity, and degrade a large amount of chlorophyll within a short hydraulic residence time (HRT). Severe damage to the microbial cell membrane can destroy the normal functions of cells, resulting in the death of microorganisms. In conclusion, the UVA+UVC+VUV/Cu-N-TiO2 system is a potential new ballast water treatment system.

UV Light Application as a Mean for Disinfection Applied in the Dairy Industry

Thermal treatment is the most popular decontamination technique used in the dairy industry to ensure food protection and prolong shelf life. But it also causes nutrient and aroma degradation, non-enzymatic browning, and organoleptic changes of dairy products. Non-thermal solutions, on the other hand, have been extensively explored in a response to rising market demand for more sustainable and safe goods. For a long time, the use of ultraviolet (UV) light in the food industry has held great promise. Irradiation with shortwave UV light has excellent germicidal properties, which can destroy a variety of microbial pathogens (for example bacteria, fungi, molds, yeasts, and viruses), at low maintenance and installation costs with minimal use of energy to preserve food without undesirable effects of heat treatment. The purpose of this review is to update the studies made on the possibilities of UV-C radiation while also addressing the essential processing factors involved in the disinfection. It also sheds light on the promise of UV light-emitting diodes (UV-LEDs) as a microbial inactivation alternative to conventional UV lamps.

The effect of ultraviolet diode radiation on the growth rate of Alternaria colonies

Phytopathogenic micromycetes induce dangerous crop diseases. Traditionally, fungicides have been used to prevent these diseases. In recent years, environmentally friendly non-chemical methods for combating fungal infections have been developed. In particular, ultraviolet (UV) treatment of various wavelengths, intensities and origins has been shown to be effective. In this work, we have analysed the effect of diode low-intensity shortwave UV radiation (UV-C) on the growth and potential viability of the mycelium of Alternaria radicina and A. alternata, the pathogens of important crops. It was shown that irradiation by UV-C diode inhibited growth of Alternaria species at the early stages of development. This effect was high in the first 3 d after UV exposure; however, after 5 d after irradiation, the growth of pathogenic fungi fully restored, suggesting that UV can be only used for partial removal of Alternaria. It was found that A. alternata is less sensitive to diode UV irradiation. The obtained results indicate that the Alternaria micromycetes, particularly, A. alternata, containing high melanin levels, are resistant to low-intensity UV-C diode irradiation.

Short Wave Ultraviolet Light (UV-C) Effectiveness in the Inactivation of Bacterial Spores Inoculated in Turbid Suspensions and in Cloudy Apple Juice

Liquid foods might present interferences in their optical properties that can reduce the effectiveness of short-wave ultraviolet radiation (UV-C) treatments used for sterilization purposes. The effect of turbidity as UV-C interference factor against the inactivation of bacterial spores was analysed by using phosphate-buffered saline solutions (PBS) of different turbidity values (2000, 2500, and 3000 NTU) which were adjusted with the addition of apple fibre. These suspensions were inoculated with spores of Bacillus subtilis and Alicyclobacillus acidoterrestris. While higher UV-C doses increased the inactivation rates of spores, these were reduced when turbidity values increased; a dose of 28.7 J/mL allowed inactivation rates of B. subtilis spores of 3.96 Log in a 2000-NTU suspension compared with 2.81 Log achieved in the 3000-NTU one. Spores of B. subtilis were more UV-C-resistant than A. acidoterrestris. Cloudy apple juice inoculated with A. acidoterrestris spores was processed by UV-C at different doses in a single pass and with recirculation of the matrix through the reactor. Inactivation increased significantly with recirculation, surpassing 5 Log after 125 J/mL compared with 0.13 Log inactivation after a single-pass treatment at the same UV-C dose. UV-C treatments with recirculation affected the optical properties (absorption coefficient at 254 nm and turbidity) of juice and increased browning as UV-C doses became higher.

Ultraviolet Radiation From a Plant Perspective: The Plant-Microorganism Context.

Ultraviolet (UV) radiation directly affects plants and microorganisms, but also alters the species-specific interactions between them. The distinct bands of UV radiation, UV-A, UV-B, and UV-C have different effects on plants and their associated microorganisms. While UV-A and UV-B mainly affect morphogenesis and phototropism, UV-B and UV-C strongly trigger secondary metabolite production. Short wave (<350 nm) UV radiation negatively affects plant pathogens in direct and indirect ways. Direct effects can be ascribed to DNA damage, protein polymerization, enzyme inactivation and increased cell membrane permeability. UV-C is the most energetic radiation and is thus more effective at lower doses to kill microorganisms, but by consequence also often causes plant damage. Indirect effects can be ascribed to UV-B specific pathways such as the UVR8-dependent upregulated defense responses in plants, UV-B and UV-C upregulated ROS accumulation, and secondary metabolite production such as phenolic compounds. In this review, we summarize the physiological and molecular effects of UV radiation on plants, microorganisms and their interactions. Considerations for the use of UV radiation to control microorganisms, pathogenic as well as non-pathogenic, are listed. Effects can be indirect by increasing specialized metabolites with plant pre-treatment, or by directly affecting microorganisms.

Relationship between the COVID-19 Outbreak and Temperature, Humidity, and Solar Radiation Across China

Novel coronavirus (COVID-19)-infected pneumonia appeared in Wuhan City, Hubei Province, China in early December 2019. Since then, COVID-19 cases have appeared in many provinces in China. While the incidence of many infectious diseases, including that of coronavirus, shows seasonal patterns, our understanding of this phenomenon is still incomplete. We used fifth-generation re-analysis data (ERA-5) released by the European Center for Long-Term Weather Forecast (ECMWF), counted the cumulatively confirmed cases in each province from January and February 2020, and analyzed the data after the outbreak of COVID-19 from early December in China. The relationship between the number of cases and the monthly average temperature, specific humidity, and downward short-wave ultraviolet (UV) radiation in each province of China, showed that COVID-19 cases were concentrated in the provinces with temperatures in range of 0–10 °C. The downward short-wave UV radiation in these areas was below 1.5 MJ·m-2·d, while the specific humidity range was between 2–6 g/kg. These meteorological and environmental factors may be the most suitable environments for potential transmission of the virus. A further understanding of the environmental factors that are prevalent in the development of COVID-19 will help predict the potential risks of the global spread of this disease, and provide support for the prevention and surveillance of countries around the world.

A Review of Exogenous Factors Implicated in the Induction of Cutaneous Melanoma

Melanoma is an increasingly pervasive form of malignant skin cancer. Cases of cutaneous melanoma are on the rise across ages and global populations, with incidence increasing significantly for both men and women. Accordingly, the identification of modifiable behaviors is of paramount concern. Previous reviews have focused on specific risk factors (e.g. UVR, pollution, diet, hormonal supplementation) to the near exclusion of other contributory factors. This review strives to report an inclusive range of exogenous variables linked to cutaneous melanoma incidence. In this review, we examine the various contributions of exogenous factors linked to the induction of cutaneous melanoma. Factors for consideration include but are not limited to: long-wave Ultraviolet A (UVA), short-wave Ultraviolet B (UVB), hormonal supplementation, diet, smoking, alcohol, vitamin supplementation, ionizing radiation, pollution, and chemical exposure.

Natural aeolian dust particles have no substantial effect on atmospheric polycyclic aromatic hydrocarbons (PAHs): A laboratory study based on naphthalene

Natural aeolian dust (AD) particles are potential carriers of polycyclic aromatic hydrocarbons (PAHs) in the atmosphere. The heterogeneous interaction between them may lead to worsened air quality and enhanced cytotoxicity and carcinogenicity of ambient particulates in downwind areas, and this topic requires in-depth exploration. In this study, AD samples were collected from four Asian dust sources, and their physical properties and compositions were determined, showing great regional differences. The physical and chemical interactions of different AD particles with naphthalene (Nap; model PAH) were observed in aqueous systems. The results showed that AD particles from the Loess Plateau had weak adsorption to Nap, which was fitted by the Langmuir isotherm. There was no obvious adsorption to Nap found for the other three AD samples. This difference seemed to depend mainly on the specific surface area and/or the total pore volume. In addition, the Nap in the aqueous solution did not undergo chemical reactions under dark conditions and longwave ultraviolet (UV) radiation but degraded under shortwave UV radiation, and 2-formylcinnamaldehyde and 1,4-naphthoquinone were the first-generated products. The degradation of Nap in the aqueous solution was probably initiated by photoionization, and the reaction rate constant (between 1.44 × 10−4 min−1 and 8.55 × 10−4 min−1) was much lower than that of Nap with hydroxyl radicals. Instead of inducing or promoting the chemical change in Nap, the AD particles slowed photodegradation due to the extinction of radiation. Therefore, it is inferred that natural AD particles have no substantial effect on the transportation and transformation of PAHs in the atmosphere.

Variation of Optical Properties of Nitrogen-doped Graphene Quantum Dots with Short/Mid/Long-wave Ultraviolet for the Development of the UV Photodetector.

Nitrogen-doped graphene quantum dots (NGQDs) synthesized from a single glucosamine precursor are utilized to develop a novel UV photodetector. Optical properties of NGQDs can be altered with short- (254 nm), mid- (302 nm), and long-wave (365 nm) ultraviolet (UV) exposure leading to the reduction of absorption from deep to mid UV (200-320 nm) and enhancement above 320 nm. Significant quenching of blue and near-IR fluorescence accompanied by the dramatic increase of green/yellow emission of UV-treated NGQDs can be used as a potential UV-sensing mechanism. These emission changes are attributed to the reduction of functional groups detected by Fourier transformed infrared spectroscopy and free-radical-driven polymerization of the NGQDs increasing their average size from 4.70 to 11.20 nm at 60 min treatment. Due to strong UV absorption and sensitivity to UV irradiation, NGQDs developed in this work are utilized to fabricate UV photodetectors. Tested under long-/mid-/short-wave UV, these devices show high photoresponsivity (up to 0.59 A/W) and excellent photodetectivity (up to 1.03 × 1011 Jones) with highly characteristic wavelength-dependent reproducible response. This study suggests that the optical/structural properties of NGQDs can be controllably altered via different wavelength UV treatment leading us to fabricate NGQD-based novel UV photodetectors providing high responsivity and detectivity.

Inherent Fluorescence Detection of Latent Fingermarks by Homemade Shortwave Ultraviolet Laser.

Detection of latent fingermarks on various substrates is critical in crime investigations. Conventional chemical methods using reagents could contaminate or even destruct biological information of samples. Here, an optical method and successful case application of detecting latent fingermarks through long-wave ultraviolet (UV) fluorescence (300-400 nm) by shortwave UV laser excitation is reported. Experimental results indicate that the recovery rate of the latent fingermarks on various paper items is in the range of 70-80% without chemical treatments. Moreover, the optical method allows for the preservation of samples for further examination, such as polymerase chain reaction (PCR) testing. The technique has also been successfully applied to a criminal case in identifying the suspect, which, to the best of our knowledge, has never been reported in real crime investigations. Therefore, such a method as UV-excited UV fluorescence in detecting latent fingermarks may be better for examination in cases where biological information of samples is needed for consequent testing.

Photoluminescence properties and energy transfer of SrZn2(PO4)2:Sn2+, Mn2+ phosphor

In this paper, SrZn2(PO4)2:Sn2+ (SZ2P:Sn2+), SrZn2(PO4)2:Mn2+ (SZ2P:Mn2+), SrZn2(PO4)2:Sn2+, and Mn2+ (SZ2P:Sn2+, Mn2+) phosphors are prepared by high temperature solid state reaction. The X-ray diffraction patterns and photoluminescence spectra of the phosphors are investigated in detail. The emission spectrum of SZ2P:Sn2+ is a wide band peaking at 461 nm due to 3P1 →1S0 transition of Sn2+, and overlaps effectively with the excitation spectrum of SZ2P:Mn2+, which shows that the absorption of SrZn2(PO4)2 host, and a series of peaks at 352, 373, 419, 431, and 466 nm, corresponding to 6A1(6S)→4E(4D), 6A1(6S)→4T2(4D), 6A1(6S)→[4A1(4G), 4E(4G)], 6A1(6S)→4T2(4G) and 6A1(6S) →4T1(4G) transition, respectively, are assigned to a wide band ranging from 200 nm to 300 nm. Therefore, luminescence intensity of Mn2+ is enhanced significantly by co-doping Sn2+ in SrZn2(PO4)2 host. According to the Dexter's energy transfer formula of multipolar interaction and Reisfeld's approximation, it is demonstrated that the energy transfer between Sn2+ and Mn2+ is due to the quadripole-quadripole interaction of the resonance transfer. The critical distance (Rc) of energy transfer is calculated to be about 1.78 nm. The tunable color is achieved by changing the doping concentrations of Sn2+ and Mn2+. The SZ2P:Sn2+, Mn2+ phosphor could emit strong blue-white light under the excitation of 254 nm ultraviolet (UV) light. The result shows that the SZ2P:Sn2+, Mn2+ is a promising phosphor for compact fluorescent lamp, and with the development of short wave UV semiconductor chip, this phosphor has potential applications in white light emitting diodes in the near future.

Modelling microbial inactivation kinetics of combined UV-H treatments in apple juice

Abstract In this investigation, temperature's effect on the ultraviolet (UV) inactivation kinetics of pathogens of concern in juices – E. coli , Salmonella Typhimurium, L. monocytogenes , and S. aureus – was studied to establish the target microorganism and process criteria for pasteurizing apple juice using combined shortwave UV-C light and mild heat (UV-H) treatments. For this purpose, mathematical models based on Geeraerd et al.'s model, which predict UV-H inactivation at different treatment temperatures, were developed for each microorganism. For comparisons, inactivation models for heat treatments were also performed in the same juice and for the same microorganisms. The UV-C inactivation notably improved at treatment temperatures between 50 and 60 °C, but the thermodependence of the UV-H resistance differed among species. This behavior was related to the thermodependence of heat treatments for each bacterium so that the target microorganism for UV-H treatments was determined based on the most heat-resistant species at each treatment temperature. Thus, E. coli was the most UV-H-resistant microorganism between 44 °C and 54 °C, requiring a UV-C dose between 13.81 J/mL (12.71 min) and 5.20 J/mL (4.78 min) in order to achieve the 5 Log 10 reduction that the U.S. Food and Drug Administration demands. Also, L. monocytogenes was the target microorganism at temperatures between 54 °C and 60 °C, requiring a UV-C dose from 5.20 J/mL (4.78 min) to 2.11 J/mL (1.93 min). The combination of UV-C and mild heat allowed for the UV-C doses and treatment times to be reduced from 49.6% to 89.1% in comparison with UV-C treatments at room temperatures. Industrial relevance In this manuscript, the target microorganism and process criteria for pasteurizing (5 Log 10 reductions) apple juice using combined shortwave UV light (UV-C) and mild heat (UV-H) treatments have been established. E. coli and L. monocytogenes resulted as the limited pathogenic microorganisms of reference in apple juice. Combining UV light with mild temperatures permitted achieving the microbial inactivation required for safe apple juice with lower UV doses and treatment times than those needed for UV treatments alone, with the reduction of the UV doses ranging from 26 to 89% depending of the treatment temperature of the apple juice.