Short-Wave Ultraviolet-Light-Based Disinfection of Surface Environment Using Light-Emitting Diodes: A New Approach to Prevent Health-Care-Associated Infections

Impact of Metabolites from Foodborne Pathogens on Cancer

Foodborne pathogens are microorganisms that cause illness through contamination, presenting significant risks to public health and food safety. This review explores the metabolites produced by these pathogens, including toxins and secondary metabolites, and their implications for human health, particularly concerning cancer risk. We examine various pathogens such as Salmonella sp., Campylobacter sp., Escherichia coli, and Listeria monocytogenes, detailing the specific metabolites of concern and their carcinogenic mechanisms. This study discusses analytical techniques for detecting these metabolites, such as chromatography, spectrometry, and immunoassays, along with the challenges associated with their detection. This study covers effective control strategies, including food processing techniques, sanitation practices, regulatory measures, and emerging technologies in pathogen control. This manuscript considers the broader public health implications of pathogen metabolites, highlighting the importance of robust health policies, public awareness, and education. This review identifies research gaps and innovative approaches, recommending advancements in detection methods, preventive strategies, and policy improvements to better manage the risks associated with foodborne pathogens and their metabolites.

UV-C disinfection of ultrasound probes: Challenges of uneven irradiance on complex surfaces

Medical devices that contact non-intact skin or mucous membranes are considered semi-critical devices and must undergo high-level disinfection (HLD) before use. Studies have identified several potential limitations of UV-C for HLD of semi-critical medical devices, including a lack of data demonstrating that UV-C irradiance can be uniformly applied to complex surfaces that contain grooves, notches and imperfections. This study focused on ultrasound probes as commonly used medical devices to show the distribution of irradiance on these surfaces. An endocavity bi-plane probe and curved array surface probe with typical surface topology were 3D scanned and modelled and an array of UV-C light-emitting diodes (LEDs) irradiating the probe surfaces was simulated (simulated wavelength: 275nm [peak], power output: 50mW). The simulated chamber wall material was equivalent to highly reflective polished aluminum with a defined reflectance of 79% at 275nm. To calculate the cycle time required to achieve HLD on probe surfaces, a minimum effective dosage of 1500mJ/cm2 based on published research was used. The simulated irradiance distribution showed a large difference between the points of highest and lowest irradiance (maximum/minimum ratio: 14.70 for the surface probe and 12.74 for the endocavity probe). In addition, the presence of shadowing effects adjacent to notches or grooves was evident. By applying an effective UV-C dose from the literature, cycle times of up to 25 minutes would be required to achieve HLD in the minimally irradiated areas of the probes used in the simulation. These findings highlight the need to demonstrate the efficacy of UV-C radiation against worst case organisms in the areas of lowest irradiance on medical devices to provide assurance these devices are reliably high level disinfected.

Fungal photoinactivation doses for UV radiation and visible light-a data collection

Nearly two million people die each year from fungal infections. Additionally, fungal crop infections jeopardize the global food supply. The use of 254 nm UVC radiation from mercury vapor lamps is a disinfection technique known to be effective against all microorganisms, and there are surveys of published UVC sensitivities. However, these mainly focus on bacteria and viruses. Therefore, a corresponding overview for fungi will be provided here, including far-UVC, UVB, UVA, and visible light, in addition to the conventional 254 nm UVC inactivation. The available literature was searched for photoinactivation data for fungi in the above-mentioned spectral ranges. To standardize the presentation, the mean log-reduction doses were retrieved and sorted by fungal species, spectral range, wavelength, and medium, among others. Additionally, the median log-reduction dose was determined for fungi in transparent liquid media. Approximately 400 evaluable individual data sets from publications over the last 100 years were compiled. Most studies were performed with 254 nm radiation from mercury vapor lamps on Aspergillus niger, Candida albicans, and Saccharomyces cerevisiae. However, the data found were highly scattered, which could be due to the experimental conditions. Even though the number of individual data sets seems large, many important fungi have not been extensively studied so far. For example, UV irradiation data does not yet exist for half of the fungal species classified as "high priority" or "medium priority" by the World Health Organization (WHO). In addition, researchers should measure the transmission of their fungal suspensions at the irradiation wavelength to avoid the undesirable effects of either absorption or scattering on irradiation results.

Postharvest of fresh white shimeji mushroom subjected to UV-C radiation

This study aimed to evaluate the postharvest characteristics of edible fresh white shimeji mushrooms under different UV-C radiation doses. The experimental design used was fully randomized, in a 5 × 8 factorial scheme (UV-C radiation dose: 0 (control), 1, 2, 3, and 4 kJ m-2 x day of analysis), with 3 replications of 70 ± 1 g mushrooms each. After exposure to different doses, they were stored at 2 ± 0.5 °C and 60 ± 3.8 % RH. Data were subjected to permutational multivariate analysis (PERMANOVA) (p ≤ 0.05). There was no significance for interaction, nor the factor day, only for the UV-C radiation doses factor. Regarding PCA, among the doses applied, the dose of 2 kJ m-2 was effective in maintaining the quality of mushrooms with greater lightness, greater whiteness index, a greater amount of total extractable polyphenols, and total antioxidant activity. In conclusion, the dose of 2 kJ m-2 was effective in maintaining the postharvest quality of white shimeji mushrooms.