The purpose of this study was to elucidate the structures and functional properties of tannin- and lignin-derived nano- and microparticles and the coatings prepared from them. Nanoparticles prepared ...from technical lignins and water-insoluble tannin obtained from softwood bark showed large differences in the suspension testing of antibacterial efficacy against methicillin-resistant
(MRSA) bacteria. A common factor among the most effective lignin nanoparticles was a relatively low molar mass of the lignin, but that alone did not guarantee high efficacy. Tannin nanoparticles showed good antibacterial activity both in suspension testing and as coatings applied onto cellulose. The nanoparticles of nitrogen-modified tannin and the small microparticles of nitrogen-modified kraft lignin exhibited promising flame-retardant parameters when applied as coatings on cellulose. These results illustrate the potential of nano- and microsized particles of unmodified and chemically modified polyphenols to provide functional coatings to cellulosic substrates for environments and applications with high hygiene and fire safety requirements.
International and national travelling has made the rapid spread of infectious diseases possible. Little information is available on the role of major traffic hubs, such as airports, in the ...transmission of respiratory infections, including seasonal influenza and a pandemic threat. We investigated the presence of respiratory viruses in the passenger environment of a major airport in order to identify risk points and guide measures to minimize transmission.
Surface and air samples were collected weekly at three different time points during the peak period of seasonal influenza in 2015-16 in Finland. Swabs from surface samples, and air samples were tested by real-time PCR for influenza A and B viruses, respiratory syncytial virus, adenovirus, rhinovirus and coronaviruses (229E, HKU1, NL63 and OC43).
Nucleic acid of at least one respiratory virus was detected in 9 out of 90 (10%) surface samples, including: a plastic toy dog in the children's playground (2/3 swabs, 67%); hand-carried luggage trays at the security check area (4/8, 50%); the buttons of the payment terminal at the pharmacy (1/2, 50%); the handrails of stairs (1/7, 14%); and the passenger side desk and divider glass at a passport control point (1/3, 33%). Among the 10 respiratory virus findings at various sites, the viruses identified were: rhinovirus (4/10, 40%, from surfaces); coronavirus (3/10, 30%, from surfaces); adenovirus (2/10, 20%, 1 air sample, 1 surface sample); influenza A (1/10, 10%, surface sample).
Detection of pathogen viral nucleic acids indicates respiratory viral surface contamination at multiple sites associated with high touch rates, and suggests a potential risk in the identified airport sites. Of the surfaces tested, plastic security screening trays appeared to pose the highest potential risk, and handling these is almost inevitable for all embarking passengers.
The goal of this study was to develop a sustainable, tannin-based option for silver-based and other current antimicrobial solutions for hospital privacy curtains. Commercial tree-derived tannins were ...characterized and their in vitro antibacterial properties against
and
were determined. Hydrolysable tannins showed greater antibacterial efficacy than condensed tannins but differences in antibacterial efficacy between any of the tannins could not be attributed to their functional group content or molar mass. Outer membrane disruption was not a significant factor in antibacterial efficacy of tannins against
. In a hospital field study, draw patches coated with hydrolysable tannins and affixed to privacy curtains reduced total bacteria count by 60% over eight weeks compared to their matching uncoated reference sides. In a follow-up laboratory study with
, very light spraying with water improved contact between bacteria and coating, enhancing the antibacterial effect by several orders of magnitude.
The worldwide spread of the SARS-CoV-2 virus has continued to accelerate, putting a considerable burden on public health, safety, and the global economy. Taking into consideration that the main route ...of virus transmission is via respiratory particles, the face mask represents a simple and efficient barrier between potentially infected and healthy individuals, thus reducing transmissibility per contact by reducing transmission of infected respiratory particles. However, long-term usage of a face mask leads to the accumulation of significant amounts of different pathogens and viruses onto the surface of the mask and can result in dangerous bacterial and viral co-infections. Zeolite imidazolate framework-8 (ZIF-8) has recently emerged as an efficient water-stable photocatalyst capable of generating reactive oxygen species under light irradiation destroying dangerous microbial pathogens. The present study investigates the potential of using ZIF-8 as a coating for face masks to prevent the adherence of microbial/viral entities. The results show that after 2 h of UV irradiation, a polypropylene mask coated with ZIF-8 nanostructures is capable of eliminating S. Aureus and bacteriophage MS2 with 99.99% and 95.4% efficiencies, respectively. Furthermore, low-pathogenic HCoV-OC43 coronavirus was eliminated by a ZIF-8-modified mask with 100% efficiency already after 1 h of UV irradiation. As bacteriophage MS2 and HCoV-OC43 coronavirus are commonly used surrogates of the SARS-CoV-2 virus, the revealed antiviral properties of ZIF-8 can represent an important step in designing efficient protective equipment for controlling and fighting the current COVID-19 pandemic.
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•ZIF-8 is applied as a coating to different face masks.•ZIF-8-based coating exhibited good stability in boiling water.•ZIF-8-based coating exhibited high antimicrobial properties against S. Aureus.•ZIF-8-based coating exhibited high antiviral properties against SARS-CoV-2’s surrogates including Bacteriophage MS2 and HCoV-OC43.
Human norovirus (HuNoV), which causes gastroenteritis, can be transmitted to food and food contact surfaces via viruscontaminated hands. To investigate this transmission in food processing ...environments, we developed a swabbing protocol for environmental samples, evaluated the stability of HuNoV in the swabs, and applied the method in the food industry. Swabs made of polyester, flocked nylon, cotton wool, and microfiber were moistened in either phosphate-buffered saline (PBS) or glycine buffer (pH 9.5) and used to swab four surfaces (latex, plastic, stainless steel, and cucumber) inoculated with HuNoV. HuNoV was eluted with either PBS or glycine buffer and detected with quantitative reverse transcription PCR. HuNoV recoveries were generally higher with an inoculation dose of 100 PCR units than 1,000 PCR units. The highest recoveries were obtained when surfaces were swabbed with microfiber cloth moistened in and eluted with glycine buffer after a HuNoV inoculation dose of 100 PCR units: 66% ± 18% on latex, 89% ±2% on plastic, and 79% ±10% on stainless steel. The highest recovery for cucumber, 45% ±5%, was obtained when swabbing the surface with microfiber cloth and PBS. The stability of HuNoV was tested in microfiber cloths moistened in PBS or glycine buffer. HuNoV RNA was detected from swabs after 3 days at 4 and 22°C, although the RNA levels decreased more rapidly in swabs moistened with glycine buffer than in those moistened with PBS at 22°C. In the field study, 172 microfiber and 45 cotton wool swab samples were taken from environmental surfaces at three food processing companies. Five (5.6%) of 90 swabs collected in 2010 and 7 (8.5%) of 82 swabs collected in 2012 were positive for HuNoV genogroup II; all positive samples were collected with microfiber swabs. Three positive results were obtained from the production line and nine were obtained from the food workers' break room and restroom areas. Swabbing is a powerful tool for HuNoV RNA detection from environmental surfaces and enables investigation of virus transmission during food processing.
BackgroundThe shortage of FFP2 and FFP3 respirators posed a serious threat to the operation of the healthcare system at the onset of the COVID-19 pandemic.AimOur aim was to develop and validate a ...large-scale facility that uses hydrogen peroxide vapour for the decontamination of used respirators.MethodsA multidisciplinary and multisectoral ad hoc group of experts representing various organisations was assembled to implement the collection and transport of used FFP2 and FFP3 respirators from hospitals covering 86% of the Finnish population. A large-scale decontamination facility using hydrogen peroxide vapour was designed and constructed. Microbiological tests were used to confirm efficacy of hydrogen peroxide vapour decontamination together with a test to assess the effect of decontamination on the filtering efficacy and fit of respirators. Bacterial and fungal growth in stored respirators was determined by standard methods.ResultsLarge-scale hydrogen peroxide vapour decontamination of a range of FFP2 and FFP3 respirator models effectively reduced the recovery of biological indicators:
and
spores, as well as model virus bacteriophage MS2. The filtering efficacy and facial fit after hydrogen peroxide vapour decontamination were not affected by the process. Microbial growth in the hydrogen peroxide vapour-treated respirators indicated appropriate microbial cleanliness.ConclusionsLarge-scale hydrogen peroxide vapour decontamination was validated. After effective decontamination, no significant changes in the key properties of the respirators were detected. European Union regulations should incorporate a facilitated pathway to allow reuse of appropriately decontaminated respirators in a severe pandemic when unused respirators are not available.
ABSTRACT
The efficiencies of potassium persulphate, isopropanol, hydrogen peroxide and peracetic acid, quaternary ammonium compound, hypochlorite, sodium dichloroisocyanurate, ethanol and phenol ...derivatives, tertiary alkylamines and dimethyl alamine betaine‐based disinfectants and a hypochlorite‐based disinfecting cleaning agent were evaluated against eight Listeria monocytogenes strains representing three different ribotypes. All the disinfectants were effective in a suspension test with an exposure time of 30 s at the lowest concentrations recommended by the manufacturer. The efficiencies on surfaces were reduced. However, on clean surfaces all the agents were considered effective when the exposure time was 5 min and the concentration was the average recommended by the manufacturer. Five of nine disinfectants and the disinfecting cleaning agent were considered effective in soiled conditions in the surface test. The most efficient agent was isopropanol‐based and the least effective was the disinfectant containing tertiary alkylamine and dimethyl alamine betaine. Differences in bactericidal efficiencies of disinfectants against different L. monocytogenes strains on meat soiled surfaces were found.
Reliable test methods for checking cleanliness are needed to evaluate and validate the cleaning process of fermentation tanks. The size of a fermentation tank can be several hundred cubic meters ...limiting the use of many traditional sampling methods since the reachable areas are scarce compared to the entire tank surface. Pilot scale tanks were used to test the applicability of various methods for evaluation of the cleanliness of fermentation tanks. The aims of this study were to find appropriate methods to detect cleanliness in pilot scale tanks, to find out which parts of the tank were difficult to clean and to optimise the cleaning procedure. This study was performed to improve the investigation of cleanability of process scale tanks and to choose suitable methods and sampling areas for use in process scale evaluations. Furthermore interpretation of data from various sampling methods is needed in cleanability assessment. The methods found to be suitable for validation of the cleanliness were visual observation of a fluorescent indicator using UV-light, a contact agar method and culturing based on swabbing and swiping with non-woven cloths. The validation of the cleaning procedure and the design of a proper cleaning system can be supported and improved using computational fluid dynamics, which through a simulation reveals areas not easily covered by the cleaning fluid. Microbial results from pilot scale studies are needed to interpret the simulation results properly. Using various methods simultaneously improves the interpretation of cleanability of tanks.
Purpose - The purpose of these studies was to investigate the cleaning and hygiene of plastic cheese moulds and plastic transportation crates and to assess the suitability of ultrasonication for ...cleaning these dairy devices on a pilot scale and to optimise these cleaning procedures.Design methodology approach - The contamination load in the various process lines was monitored by use of chemical methods, i.e. EDTA titration and COD measurement for organic residues and various microbiological techniques for microbial contaminants. Ultrasonication cleaning procedures for cheese moulds were planned among parameters applicable to the process environment. The Taguchi method design of experiments was also used for the cleaning of milk transportation crates.Findings - Ultrasonication was found to be a suitable cleaning method for both cheese moulds and transportation crates. Acceptable cleaning results were achieved using short cleaning procedures with a temperature under 60°C. Various types of cleaning agents can be used together with ultrasonication and the plastic materials in the utensils tolerated ultrasonication. The quality and the efficacy of the cleaning liquid used in the ultrasonic bath in the dairy plant were rapidly diluted due to the accumulation of organic soil. To ensure the effectiveness of cleaning, the quality of cleaning liquid should be measured frequently and threshold limits for changing the cleaning liquid should be set. The COD measurement proved to be practical for monitoring the organic load of the cleaning liquid and traditional culturing, as well as commercial culturing applications, e.g. Petrifilm™ AC and DryCult® TPC can easily be used for monitoring the level of microbial contamination.Research limitations implications - No major limitations, apart from the required investments, were found for applying the ultrasonication in the cleaning of dairy devices, e.g. plastic cheese moulds and plastic milk transportation crates.Originality value - The work is of value in highlighting the potential use for ultrasonication in improving the cleaning procedure of returnable milk transportation crates made of plastic.
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