Evaluation of approaches to increase the effectiveness of various disinfectants against biofilm communities of different ages

Disinfectants are used as the main agents against microorganisms circulating on the surfaces of food enterprises. However, the adaptive ability of microorganisms to form biofilms complicates the process of surface cleaning and reduces the effectiveness of disinfectants. Modern disinfectants act against freely circulating microflora, but it is known that they are not always effective against biofilms. The purpose of this study was to investigate effective disinfectant compositions with bactericidal effect on binary bacterial biofilms of different ages. The article describes the effects of disinfectants based on chlorine, peracetic acid and quaternary ammonium compounds with enzymes in concentrations recommended by the manufacturer and increased several times on Salmonella 38, Brochothrix thermosphacta 2726 and Staphylococcus equorum 2736 planktonic cultures and binary biofilms. Binary biofilms of different ages (2 and 9 days old) were exposed to disinfectants with various active ingredients in combination with adjuvants, i. e. hydrogen peroxide 6% and various concentrations of isopropyl alcohol (30%). All products in concentrations recommended by the manufacturer did not have a disinfectant effect against the studied biofilm cultures. As a result of the work, it was found that the most effective disinfectants against multispecies biofilms were quaternary ammonium compounds in combination with enzymes and chlorine in combination with isopropyl alcohol (30%). The results obtained allow to expand knowledge about effective methods for controlling biofilms.Disinfectants are used as the main agents against microorganisms circulating on the surfaces of food enterprises. However, the adaptive ability of microorganisms to form biofilms complicates the process of surface cleaning and reduces the effectiveness of disinfectants. Modern disinfectants act against freely circulating microflora, but it is known that they are not always effective against biofilms. The purpose of this study was to investigate effective disinfectant compositions with bactericidal effect on binary bacterial biofilms of different ages. The article describes the effects of disinfectants based on chlorine, peracetic acid and quaternary ammonium compounds with enzymes in concentrations recommended by the manufacturer and increased several times on Salmonella 38, Brochothrix thermosphacta 2726 and Staphylococcus equorum 2736 planktonic cultures and binary biofilms. Binary biofilms of different ages (2 and 9 days old) were exposed to disinfectants with various active ingredients in combination with adjuvants, i. e. hydrogen peroxide 6% and various concentrations of isopropyl alcohol (30%). All products in concentrations recommended by the manufacturer did not have a disinfectant effect against the studied biofilm cultures. As a result of the work, it was found that the most effective disinfectants against multispecies biofilms were quaternary ammonium compounds in combination with enzymes and chlorine in combination with isopropyl alcohol (30%). The results obtained allow to expand knowledge about effective methods for controlling biofilms

Simultaneous observations of the 557.7 nm airglow and stimulated electromagnetic emission during HF pumping of the ionosphere with diagnostic schedule: First results

The first results on simultaneous observation for artificial airglow emission at 557.7 nm (green line) and stimulated electromagnetic emission (SEE) during HF pumping of the ionosphere with specially designed HF pulsing sequence are reported. Ionospheric radio pumping was performed at the "Sura" radio facility situated near Niznhny Novgord, Russia. The measurements of airglow were handled at the Astronomical Observatory of Kazan State University (220 km to the east of "Sura" facility) by the astronomical telescope AZT-14 connected with the electric photometer. During several "Sura" runs enhancements of the airglow intensity in time with pump wave pulses were observed after the pump wave switch from continuous transmission to low duty cycle pulse transmission. The airglow and SEE intensities and SEE decay rates were correlated. © 2004 COSPAR. Published by Elsevier Ltd. All rights reserved

Studies of artificial airglow emission at 557.7 nm (green line) of upper atmosphere caused by "Sura" facility

Some experimental results of artificial airglow emission at 557.7 nm (green line) during HF pumping of the ionosphere with specially designed HF pulsing sequence are reported. Ionospheric radio pumping was performed at the "Sura" radio facility situated near Niznhny Novgord, Russia. The measurements of airglow were handled at the Astronomical Observatory of Kazan State University (220 km to the east of "Sura" facility) by the astronomical telescope AZT-14 connected with the electric photometer. During several "Sura" runs enhancements of the airglow intensity in time with pump wave pulses were observed after the pump wave switch from continuous transmission to low duty cycle pulse transmission

Evaluating the effect of various types of disinfectants on bacterial biofilms

Biofilm formation on equipment surfaces is a potential food safety hazard, providing increased resistance and persistence of pathogens and spoilage microorganisms in food production environments. The issue of preventing the biofilm formation is extremely important, since a wide range of disinfectants does not always provide the proper effect. The article discusses the antimicrobial effectiveness of disinfectants with various active ingredients (based on active chlorine, peracetic acid and quaternary ammonium compounds (QAC) with enzymatic substances) on binary biofilms. The objects of the study were the strains of pathogenic and opportunistic microorganisms isolated from abiotic surfaces of food production environments and food products. Different effects of disinfectants on biofilms formed by bacteria have been established. Disinfectant based on peracetic acid and chlorine had the greatest effect on binary biofilms of Brochothrix thermosphacta/Salmonella spp. and Staphylococcus equorum/Salmonella spp. The greatest antimicrobial effect on biofilm of Listeria monocytogenes 12/Pseudomonas azotoformans 6 was shown by a chlorine-based disinfectant. Disinfectants based on chlorine and QAC with enzymatic substances were most effective against the binary biofilm of L. monocytogenes 12/Salmonella spp. 14. However, none of the disinfectants had absolute antimicrobial effectiveness against the studied binary biofilms. Biofilm-forming microorganisms have shown resistance to the recommended concentrations of disinfectants. Therefore, currently, it is extremely important to revise approaches to hygiene at enterprises by finding working concentrations of new antimicrobial agents and new procedure that are effective for destroying biofilms

Loop-mediated isothermal amplification (LAMP) method for fast detection of Campylobacter spp in meat food products and environmental objects of a processing plant’s

There is constant necessity of developing the accurate and fast methods for detection of foodborne pathogens. Microorganisms of Campylobacter genus are one of the main causes of foodborne diseases worldwide. Fast identification of Campylobacter at all stages of the food life cycle is an efficient strategy to control foodborne campylobacteriosis. This article the authors evaluated a commercial loop-mediated isothermal amplification (LAMP) system with bioluminescence, called as the 3M™ Molecular Detection Analysis (MDA), which was used to find Campylobacter in food products with the help of a certain standard method, which is referred to as the reference method. The results of this study showed that the commercial LAMP based method is as efficient as the reference method, and features high specificity and minimum determinability (sensitivity). The LAMP based method has been shown to be a fast and reliable method for detection of Campylobacter spp. scarce presence (10 CFU/25 g) in meat, meat products, as well as carcass swabs and production facilities’ environment. The LAMP analysis required about 24–27 hours to achieve a result. However the LAMP based method will facilitate the detection of Campylobacter, as it provides much easier and faster detection of Cam  pylobacter spp., including Campylobacter jejuni/Campylobacter coli, than standard microbiological methods. The LAMP based method is an efficient tool to prevent the spreading of Campylobacter spp. contamination in food products.There is constant necessity of developing the accurate and fast methods for detection of foodborne pathogens. Microorganisms of Campylobacter genus are one of the main causes of foodborne diseases worldwide. Fast identification of Campylobacter at all stages of the food life cycle is an efficient strategy to control foodborne campylobacteriosis. This article the authors evaluated a commercial loop-mediated isothermal amplification (LAMP) system with bioluminescence, called as the 3M™ Molecular Detection Analysis (MDA), which was used to find Campylobacter in food products with the help of a certain standard method, which is referred to as the reference method. The results of this study showed that the commercial LAMP based method is as efficient as the reference method, and features high specificity and minimum determinability (sensitivity). The LAMP based method has been shown to be a fast and reliable method for detection of Campylobacter spp. scarce presence (10 CFU/25 g) in meat, meat products, as well as carcass swabs and production facilities’ environment. The LAMP analysis required about 24–27 hours to achieve a result. However the LAMP based method will facilitate the detection of Campylobacter, as it provides much easier and faster detection of Cam  pylobacter spp., including Campylobacter jejuni/Campylobacter coli, than standard microbiological methods. The LAMP based method is an efficient tool to prevent the spreading of Campylobacter spp. contamination in food products

Propagation of HF radio waves over northerly paths: measurements,simulation and systems aspects

Large deviations in the direction of arrival of ionospherically propagating radio signals from the Great Circle Path (GCP) have serious implications for the planning and operation of communications and radiolocation systems operating within the HF-band. Very large deviations are particularly prevalent in the polar and sub-auroral regions where signals often arrive at the receiver with bearings displaced from the great circle direction by up to ±100° or more. Measurements made over several paths are presented in this paper, and the principle causes of off-great circle propagation outlined. Significant progress has been made in modelling the propagation effects and work is now in hand to incorporate the results into tools to aid the planning and operation of HF radio systems operating at northerly latitudes

Optical characterization of antirelaxation coatings

Antirelaxation coatings (ARC) are used in optical cells containing alkali metal vapor to reduce the depolarization of alkali atoms after collisions with the cell walls. The long-lived ground state polarization is a basis for development of atomic clocks, magnetometers, quantum memory, slow light experiments, precision measurements of fundamental symmetries etc. In this work, a simple method for measuring the number of collisions of the alkali atoms with the cell walls without atomic spin randomization (Nasyrov et al., Proc. SPIE (2015)) was applied to characterize the AR properties of two PDMS coatings prepared from different solutions in ether (PDMS 2% and PDMS 5%). We observed influence of the light-induced atomic desorption (LIAD) on the AR properties of coatings

Mutual Allocation of the Artificial Airglow Patches and Large-Scale Irregularities in the HF-Pumped Ionosphere

©2018. American Geophysical Union. All Rights Reserved. The paper reports first simultaneous observations of artificial emission of 630-nm oxygen red line, along with perturbations of slant total electron content (STEC). They were induced by the high-frequency (HF) ionospheric heating produced by the SURA facility situated near Nijniy Novgorod, Russia. The HF heating affects differently the optical emission and STEC. While the patches of the artificial airglow are close to the area of the reduced STEC, the STEC increases at the periphery of the patches. Thus, the artificial airglow occurs mostly inside the large plasma cavities

Cosmogenic 11C production and sensitivity of organic scintillator detectors to pep and CNO neutrinos

Several possible background sources determine the detectability of pep and CNO solar neutrinos in organic liquid scintillator detectors. Among such sources, the cosmogenic 11C nuclide plays a central role. 11C is produced underground in reactions induced by the residual cosmic muon flux. Experimental data available for the effective cross section for 11C by muons indicate that 11C will be the dominant source of background for the observation of pep and CNO neutrinos. 11C decays are expected to total a rate 2.5 (20) times higher than the combined rate of pep and CNO neutrinos in Borexino (KamLAND) in the energy window preferred for the pep measurement, between 0.8 and 1.3 MeV. This study examines the production mechanism of 11C by muon-induced showers in organic liquid scintillators with a novel approach: for the first time, we perform a detailed ab initio calculation of the production of a cosmogenic nuclide, 11C, taking into consideration all relevant production channels. Results of the calculation are compared with the effective cross sections measured by target experiments in muon beams. This paper also discusses a technique for reduction of background from 11C in organic liquid scintillator detectors, which allows to identify on a one-by-one basis and remove from the data set a large fraction of 11C decays. The background reduction technique hinges on an idea proposed by Martin Deutsch, who suggested that a neutron must be ejected in every interaction producing a 11C nuclide from 12C. 11C events are tagged by a three-fold coincidence with the parent muon track and the subsequent neutron capture on protons.Comment: 11 pages, 6 figures; added one section detailing comparison with previous estimates; added reference

Airglow during ionospheric modifications by the sura facility radiation. Experimental results obtained in 2010

We present the results of studying the structure and dynamics of the HF-heated volume above the Sura facility obtained in 2010 by measurements of ionospheric airglow in the red (λ = 630 nm) and green (λ = 557.7 nm) lines of atomic oxygen. Vertical sounding of the ionosphere (followed by modeling of the pump-wave propagation) and measurements of stimulated electromagnetic emission were used for additional diagnostics of ionospheric parameters and the processes occurring in the heated volume. © 2012 Springer Science+Business Media, Inc