Exploring thermosonication as non-chemical disinfection technology for strawberries

The scope of this work was to study the efficacy of the combination of sonication at 35 or 130 kHz with three temperature treatments: 20, 50 and 55 ºC, on the population of artificially inoculated Listeria innocua in strawberries, and on their overall quality. Prior in vitro results showed that temperature was the main factor in decreasing L. innocua population: a maximum of 3.8 log reductions was obtained with sonication at 130 kHz and 55 ºC for 15 min Treatments combining—or not—sonication at 130 kHz with mild temperatures (50 and 55 ºC) for 5 or 10 min were able to decrease about 3 log units of artificially inoculated L. innocua in strawberries and about 2 log units of total aerobic mesophilic and yeasts and molds populations naturally occurring in strawberries. Thermosonication treatments did not exert a detrimental impact on fruit quality, except for those at the higher temperatures and times, which caused a change in color to more purplish and a little softening of the strawberries, which were proposed to be assessed for further processing other than fresh commercialization. Overall, the impact of sonication in fresh strawberries needs to be further investigated to find the adequate conditions to enhance the effects of temperature itself.

Discrimination and isolation of the virus from free RNA fragments for the highly sensitive measurement of SARS-CoV-2 abundance on surfaces using a graphene oxide nano surface

It is highly important to sensitively measure the abundance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on various surfaces. Here, we present a nucleic acid-based detection method consisting of a new sample preparation protocol that isolates only viruses, not the free RNA fragments already present on the surfaces of indoor human-inhabited environments, using a graphene oxide-coated microbead filter. Wet wipes (100 cm2), not cotton swabs, were used to collect viruses from environmental surfaces with large areas, and viruses were concentrated and separated with a graphene oxide-coated microbead filter. Viral RNA from virus was recovered 88.10 ± 8.03% from the surface and free RNA fragment was removed by 99.75 ± 0.19% from the final eluted solution. When we tested the developed method under laboratory conditions, a 10-fold higher viral detection sensitivity (Detection limit: 1 pfu/100 cm2) than the current commercial protocol was observed. Using our new sample preparation protocol, we also confirmed that the virus was effectively removed from surfaces after chemical disinfection; we were unable to measure the disinfection efficiency using the current commercial protocol because it cannot distinguish between viral RNA and free RNA fragments. Finally, we investigated the presence of SARS-CoV-2 and bacteria in 12 individual negative pressure wards in which patients with SARS-CoV-2 infection had been hospitalized. Bacteria (based on 16 S DNA) were found in all samples collected from patient rooms; however, SARS-CoV-2 was mainly detected in rooms shared by two patients.

Thermal and chemical disinfection of water and biofilms: only a temporary effect in regard to the autochthonous bacteria

Thermal and chemical disinfection of technical water systems not only aim at minimizing the level of undesired microorganisms, but also at preventing excessive biofouling, clogging and interference with diverse technical processes. Typically, treatment has to be repeated in certain time intervals, as the duration of the effect is limited. The transient effect of disinfection was demonstrated in this study applying different treatments to water and biofilms including heat, chlorination, a combination of hydrogen peroxide and peracetic acid and monochloramine. Despite the diverse treatments, the reduction in live bacteria was followed by regrowth in all cases, underlining the universal validity of this phenomenon. The study shows that autochthonous bacteria could reach the concentrations given prior to treatment. The reason is seen in the nutrient concentration that has not changed and that forms the basis for regrowth. Nutrients are released by disinfection from lysed cells or are still fixed in dead biomass that is subsequently scavenged by necrotrophic growth. Treatment cycles therefore only provide a transient reduction of water microbiology if nutrients are not removed. When aiming at greater sustainability of the effect, biocidal treatment has to be equally concerned about nutrient removal by subsequent cleaning procedures as about killing efficiency.

Evaluation of the effectiveness of chemical disinfection agents against the Epstein-Barr virus

The widespread spread of infection caused by the Epstein-Barr virus (EBV), the lack of registered vaccines, the possibility of implementing a transmission mechanism in medical organizations, determine disinfection as the main method of preventing this disease. The aim is to evaluate the effectiveness of chemical disinfection agents approved for use in the Russian Federation in relation to EBV-infected cell culture with quantitative DNA determination by polymerase chain reaction. Working solutions of complex disinfectants used for the treatment of medical devices were introduced into samples of EBV-infected B-cell culture in the concentration and exposure specified in the instructions (0.1 %; 60 min.). Then, the quantitative determination of the EBV DNA was performed. Chlorine-containing disinfectants, combined preparations based on aldehydes and guanidines per hour, as well as guanidines per hour and triamines, provided complete destruction of genetic material, while the combination of H with triamines led only to a decrease in the concentration of EBV DNA from 5.0 · 106 copies/ml to 2.4 · 106 copies/ml (by 2.1 times), which may not be enough to fully ensure biological safety when processing medical devices (sensors of ultrasound diagnostics devices, etc.), which are not subject to sterilization. The inability to determine the viability of EBV after treatment with disinfectants due to the initial presence of the virus in the B-cell culture makes the molecular biological method the only acceptable one at this stage and requires the search for new models – cell cultures intact to EBV or biological objects (laboratory animals). Keywords: Epstein-Barr virus, disinfection, quaternary ammonium compounds, triamines, aldehydes, guanidines, active chlorine releasing agents.

Additive Manufacturing of Plastics Used for Protection against COVID19—The Influence of Chemical Disinfection by Alcohol on the Properties of ABS and PETG Polymers

In this paper, the influence of disinfection on structural and mechanical properties of additive manufactured (AM) parts was analyzed. All AM parts used for a fight against COVID19 were disinfected using available methods—including usage of alcohols, high temperature, ozonation, etc.—which influence on AM parts properties has not been sufficiently analyzed. During this research, three types of materials dedicated for were tested in four different disinfection times and two disinfection liquid concentrations. It has been registered that disinfection liquid penetrated void into material’s volume, which caused an almost 20% decrease in tensile properties in parts manufactured using a glycol-modified version of polyethylene terephthalate (PETG).

Bacteriophage treatment before chemical disinfection can enhance removal of plastic surface-associated Pseudomonas aeruginosa

Opportunistic pathogens can linger on surfaces in hospital and building plumbing environments, leading to infections in at-risk populations. Further, biofilm-associated bacteria are protected from removal and inactivation protocols, such as disinfection. Bacteriophages show promise as tools to treat antibiotic resistant infections. As such, phages may also be useful in environmental applications to prevent newly acquired infections. In the current study, the potential of synergies between bacteriophage and chemical disinfection of the opportunistic pathogen Pseudomonas aeruginosa was assessed under various conditions. Specifically, surface-associated P. aeruginosa was treated with various concentrations of phages (P1 or JG004), chemical disinfectant (sodium hypochlorite or benzalkonium chloride), or combined sequential treatments under three distinct attachment models (spot inoculations, dry biofilms, and wet biofilms). Phages were very effective at removing bacteria in spot inoculation (>3.2 log 10 removal) and wet biofilms (up to 2.6 log 10 removal), while phages prevented regrowth of dry biofilms in the application time. In addition, phage treatment followed by chemical disinfection inactivated more P. aeruginosa under wet biofilm conditions better than either treatment alone. This effect was hindered when chemical disinfection was applied first, followed by phage treatment, suggesting additive benefits of combination treatments are lost when phage is applied last. Further, we confirm prior evidence of greater phage tolerance to benzalkonium chloride relative to sodium hypochlorite, informing choices for combination phage-disinfectant approaches. Overall, this paper further supports the potential of using combination phage and chemical disinfectant treatments to improve inactivation of surface-associated P. aeruginosa . Importance Phages are already utilized in the healthcare industry to treat antibiotic resistant infections, such as on implant-associated biofilms and in compassionate care cases. Phage treatment could also be a promising new tool to control pathogens in the built environment, preventing infections from occurring. This study shows that phage can be combined effectively with chemical disinfectants to improve removal of wet biofilms and bacteria spotted onto surfaces while preventing regrowth in dry biofilms. This has the potential to improve pathogen containment within the built environment and drinking water infrastructure to prevent infections of opportunistic pathogens.

Water disinfection using acoustic cavitation: A mini review

The waterborne disease is a major concern for India and root cause of this non-ability of water disinfection technology at affordable cost to all. Hence it is necessary to understand the disinfection of water to achieve goal of healthy society. Various methods and technologies like Chlorination, iodine, silver, coagulation flocculation, iron Nano particles, UV, Solar disinfection, distillation, Reverse osmosis, slow sand filters, activated charcoal filter, electrochemical oxidation, cavitation, plasma techniques, electrocoagulation, photo catalysis and many more have been evolved over the years. Despite of availability of techniques for water disinfection, but larger scale application still is a major challenge, especially in developing countries where almost eighty percent diseases are cause by waterborne. Acoustic cavitation is base technique highly useful for water disinfection. This mini review discussed various aspects of acoustic cavitation and potential application for water disinfection. Acoustic cavitation with chemical disinfection techniques is also very beneficial because it reduces the use of chemical so production of byproducts reduces automatically.

Chemical Disinfection of Potato Cutting Machinery to Avoid Dissemination of Clavibacter sepedonicus

A potential cause of the dissemination of the potato ring rot bacterium Clavibacter sepedonicus (Cs) is the use of automated seed potato cutters. The present study focuses on the question of whether disinfection practices are sufficient to prevent the transmission of Cs from contaminated machine parts to a new tuber lot. The disinfection efficacy was determined by establishing the culturability of Cs that remained after spray application of sodium-p-toluenesulfochloramide solution on clean and fouled specimens of machinery material that had been provided with an imprint of Cs biofilm. Although conventional spraying, with the authorized concentration of sodium-p-toluenesulfochloramide, of inoculated rubber, PVC and lacquered steel led to a substantial decrease of colony forming units, the treatment was insufficient for complete eradication of Cs. The presence of dirt negatively affected the efficacy of the disinfectant.