Due to the COVID19 pandemic, solutions to automate disinfection using UV-C combined with mobile robots are beginning to be explored. It has been proved that the use of these systems highly reduces the risk of contagion. However, its use in real applications is not being as rapid as it needs to be. One of the main market input barriers is the fear of degrading facilities. For this reason, it is crucial to perform a detailed study on the degradation effect of UV-C light on inert materials. This experimental study proves that, considering exposition times equivalent to several work years in hospital rooms, only the appearance of the material is affected, but not their mechanical functionalities. This relevant result could contribute to accelerate the deployment of these beneficial disinfection technologies. For that purpose, a colorimetry test, tensile strength test, and analysis of the surface microstructure were carried out. The results showed that polymers tend to turn yellow, while fabrics lose intensity depending on the color. Red is hardly affected by UV-C, but blue and green are. Thus, this study contributes to the identification of the best materials and colors to be used in rooms subjected to disinfection processes. In addition, it is shown how the surface microstructure of the materials is altered in most of the materials, but not the tensile strength of the fabrics.

SARS-CoV-2 is responsible for the COVID-19 pandemic, which has caused almost 570 million infections and over six million deaths worldwide. To help curb its spread, solutions using ultraviolet light (UV) for quick virus inactivation inside buildings without human intervention could be very useful to reduce chances of contagion. The UV dose must be sufficient to inactivate the virus considering the different materials in the room, but it should not be too high, not to degrade the environment. In the present study, we have analyzed the ability of a 254nm wavelength UV-C lamp to inactivate dried samples of SARS-CoV-2 exposed at a distance of two meters, simulating a full-scale scenario. Our results showed that virus inactivation was extremely efficient in most tested materials, which included plastic, metal, wood, and textile, with a UV-C exposure of only 42s (equivalent to 10mJ/cm2). However, porous materials like medium density fibreboard, were hard to decontaminate, indicating that they should be avoided in hospital rooms and public places.

Cider represents a habitat that allows the growth of different bacteria involved in the fermentation process. The process involves interactions between yeasts, lactic acid bacteria (LAB), and acetic acid bacteria (AAB). The activity of some bacteria is responsible for cider spoilage. This study examines the efficacy of UVC for reducing the microbial load in natural cider and characterizes the different LAB and AAB colonies. For this purpose, an inline UVC treatment has been designed and fabricated. Different flow rates have been tested. Moreover, the presence of the genes related to cider spoiling has been studied by PCR. The results have shown that UVC irradiation has been effective in all flow rates by reducing the bacterial load significantly, by 90%-99%. The presence of an enzyme related to bitterness has been found in some LAB. In conclusion, the developed UVC equipment has the potential effect of reducing the microbial load in the beverage. Novelty impact statement This article shows a significant reduction of the microbial load in beverages such as cider. The results show an important advance for the treatment of these beverages in the industry as it allows to control the microbial load present and increases the shelf life of the products. Furthermore, this research could increase the shelf life of the beverages in a market that is constantly growing.

Impedance spectroscopy analysis (IS) has awakened a great interest for many industrial applications and sectors for the implementation of novel monitoring capabilities. More specifically, microelectrode-based sensors are increasingly being used to analyze electrical or electrochemical changes in liquid samples, as well as other effects such as biofouling, particle adhesion, etc. However, real environmental conditions are usually subjected physiochemical changes that affect the impedance measurement. In this context, it is difficult to isolate the effect of only one parameter (Le., conductivity of the medium) from the other ones. This work is focused specifically on the analysis of the influence of temperature and pH on the impedance measurements. Different experiments were carried out using interdigitated microelectrodes (IDE) sensors for a geometry range in wine samples to adjust a proposed mathematical model of the impedance behavior. In the case of fermentation processes of alcoholic beverages, this methodology will help to isolate the chemical changes measured by impedance from temperature or pH variation. This model also provides the significance of the effect of each parameter on the impedance values. After the experimental validation, the model was used to correct the impedance values accordingly to the variation of each parameter showing its applicability to the real field. Finally, the proposed methodology can be easily applied and extended to other environments and sensors types. (C) 2018 Elsevier B.V. All rights reserved.

Brettanomyces is a yeast species responsible for wine and cider spoilage, producing volatile phenols that result in off-odors and loss of fruity sensorial qualities. Current commercial detection methods for these spoilage species are liable to frequent false positives, long culture times and fungal contamination. In this work, an interdigitated (IDE) biosensor was created to detect Brettanomyces using immunological reactions and impedance spectroscopy analysis. To promote efficient antibody immobilization on the electrodes¿ surface and to decrease non-specific adsorption, a Self-Assembled Monolayer (SAM) was developed. An impedance spectroscopy analysis, over four yeast strains, confirmed our device's increased efficacy. Compared to label-free sensors, antibody biosensors showed a higher relative impedance. The results also suggested that these biosensors could be a promising method to monitor some spoilage yeasts, offering an efficient alternative to the laborious and expensive traditional methods.

Brettanomyces bruxellensis is considered one of the most relevant spoilage yeasts in the production of alcoholic beverages, especially for wine and cider. During fermentation and later storage, these yeasts can cause changes in the characteristics of the product, ruining the aroma and taste. The presence of Brettanomyces causes a decrease in the quality of the final products and important economic losses. The current work presents a detection method based on impedance spectroscopy analysis using label-free interdigitated microelectrode (IDE) based sensors for spoilage yeast detection. Different conditions (static and stirring) were tested in Brettanomyces cultures inside reactors in order to evaluate the growth behavior. Our results indicate a faster response and an 8% increase of the relative variation of the impedance under stirring condition due to biofilm formation onto the surface of the sensors. Equivalent circuit analysis also confirmed that the difference was caused by the larger biofilm formation under dynamic conditions. The results suggest that this technology could be applied for the early detection of spoilage yeast in wine and cider industries, providing more efficient methods to achieve a higher quality of the final products. (C) 2017 Elsevier B.V. All rights reserved.

Bacterial biofilms led to numerous problems in a wide variety of sectors as the medical environment, the food and water industry, or the naval sector. Completely developed biofilms are nearly impossible to eliminate due to the high antibiotic resistance these complex systems present. The lack of evidential indicators of their presence at the first stages of development makes antimicrobial treatments late and inadequate. Therefore, it is necessary to find new methods for the early detection of biofilm development in order to improve the efficiency of treatments by exposing bacterial cells before encapsulation in the extracellular matrix. For this purpose, this paper presents a real-time analysis of bacterial adhesion and biofilm growth by means of electrochemical measurements. Cyclic voltammetry and differential pulse voltammetry were performed with thin-film interdigitated microelectrode-based sensors. More sensitive and selective measurements were obtained with the second technique. Bacterial adhesion was detected 1 h after the initial inoculum, and three different redox centers were identified on bacterial surfaces. Finally, bacterial biofilm growth phases (lag, exponential, and stationary) were identified through the electrochemical measurements.

This paper describes the design, implementation and validation of a sensitive and integral technology solution for endotoxin detection. The unified and portable platform is based on the electrochemical detection of endotoxins using a synthetic peptide immobilized on a thin-film biosensor. The work covers the fabrication of an optimized sensor, the biofunctionalization protocol and the design and implementation of the measuring and signalling elements (a microfluidic chamber and a portable potentiostat-galvanostat), framed ad hoc for this specific application. The use of thin-film technologies to fabricate the biosensing device and the application of simple immobilization and detection methods enable a rapid, easy and sensitive technique for in situ and real time LPS detection.

In this paper, a biological protocol for endotoxin detection has been developed and optimized by quartz crystal microbalance (QCM). The parameters involved in the formation of the self-assembled monolayer (SAM) have been analyzed, and a study of the pH of the ligand buffer has been performed in order to find the best condition for the ligand immobilization and, in consequence, for the endotoxin detection. The detection limit obtained with the characterized biological protocol corresponds to 1.90 mu g/ml. The effectiveness of the optimized biological protocol has been analyzed by cyclic voltammetry analysis.

In this paper, the implementation and characterization of a hand-held and simple biosensor for in-situ endotoxin determination are described. The integrated biosensor developed here is based on the electrochemical detection of endotoxin using polymyxin B as bioreceptor immobilized onto gold electrodes via a self-assembled monolayer. The cyclic voltammetry, electrochemical impedance spectroscopy, and atomic force microscopy were used to characterize the biosensor performance and properties throughout the functionalization process. In addition, a comparative analysis of the behavior and features of two alternative electrochemical techniques for endotoxin detection was carried out. The biosensing device fabricated by thin-film technologies provided a simple and robust method to detect low concentrations of endotoxin.