Decontamination Efficacy Research Articles

In vitro human skin decontamination efficacy of MOF-808 in decontamination lotion following exposure to the nerve agent VX

Metal-organic frameworks (MOFs) have shown promising properties for removal of chemical warfare agents, in particular for material decontamination and functionalized fabrics. The MOF-properties could also be beneficial for skin decontamination, especially when exposed to highly toxic and low volatile nerve agents. In such exposures, efficient decontamination is crucial for adequate medical management. In the present study, seven zirconium-based MOFs were evaluated for their ability to degrade VX and subsequently tested in vitro for decontamination of VX on human dermatomed skin.Of the MOFs evaluated, MOF-808 showed the greatest ability to degrade VX in an alkaline buffer with complete degradation of VX within 5 min. PCN-777, Zr-NDC and NU-1000 displayed degradation half-lives of approximately 10 min. When including MOF-808 in a skin friendly carrier with slightly acidic pH, a decreased agent degradation rate was observed, requiring over 24 h to reach complete degradation. In skin decontamination experiments, MOF-808 enhanced the efficacy compared to the carrier alone, essentially by improved agent absorption. Adding MOF-808 to Reactive Skin Decontamination Lotion (RSDL) did not improve the high effectiveness of RSDL alone. The present study showed that including MOF in skin decontamination lotions could be beneficial. Further studies should include optimizing the particulates and formulations.

Novel technique using cold atmospheric plasma coupled with air-polishing for the treatment of titanium discs grown with biofilm: An in-vitro study

ObjectivesThe aim of the present study was to assess the decontamination efficacy and titanium surface alterations of erythritol based air abrasion (AA) and cold atmospheric plasma (CAP) targeting a human complex biofilm. MethodsSaliva collected from a peri-implantitis patient was used to develop in vitro human biofilm over titanium discs with machined (group A) and moderately rough (group B) surface. The discs were treated with AA, experimental CAP or a combination of both treatments (COM). The amount of biofilm on the discs was measured by crystal violet (CV). Surface features and roughness before and after treatment were assessed by SEM and laser profilometry, respectively. The data were statistically analyzed using Kruskal Wallis followed by Dunn's multiple comparison test after being checked for normality by Shapiro-Wilk test. ResultsAll the discs in group A performed better to treatments compared to group B. In both groups, CV data showed significantly lower amount of biofilm after AA treatment compared to CAP (p<0.05). Cleaning efficacy revealed relevant decontamination of both the surfaces following AA and COM treatments and almost complete biofilm removal after AA application on group A (99.92%). SEM analysis demonstrated no post-treatment alterations on the discs and laser profilometry did not show statistically significant changes in Sa and Sdr values. SignificanceDecontamination with AA delivering erythritol with or without CAP is highly effective in biofilm removal from different titanium surfaces. All the tested treatments, including CAP showed no noticeable alterations of the titanium discs surface features. Further in vivo studies are necessary to understand the potential of CAP technology in implant surface decontamination.

Effects of direct and in-package pulsed light treatment on inactivation of E. coli O157:H7 and reduction of microbial loads in Romaine lettuce

The microbial safety of fresh produce continues to be a real concern. Novel nonthermal technologies are required to lessen the risk of pathogen contamination. The objective of this research was to develop and evaluate the effects of direct and in-package pulsed light (PL) treatment on the survival of E. coli O157:H7 in Romaine lettuce. Treatment influence on reduction of background microbial loads of Romaine lettuce was also explored. A three strain-cocktail of E. coli O157:H7 was selected for inoculum preparation for their link with foodborne outbreaks. Surface inoculated Romaine lettuce pieces (2.5 × 2.5 cm) was subjected to pulsed light treatment for a maximum of 1 min (63 J/cm2). Polyethylene (PE) films of 0.00254, 0.00508 and 0.00762 cm thickness with ample UV transmission (54–83%) ability were used for packaging. PL treatment of 10 s, equivalent to a dose of 10.5 J/cm2, was considered optimum beyond which wilting of leaves was observed. Both direct and in-package treatment provided greater than 1 log reduction of the pathogen in 1 s (1.05 J/cm2). Direct treatment resulted in 2.68 ± 0.37 log CFU/g reduction of E. coli O157:H7 at optimal dose, whereas log reductions were decreased to 2.52 ± 0.19, 2.31 ± 0.34 and 2.18 ± 0.25 log CFU/g for Romaine lettuce in 0.00254, 0.00508 and 0.00762 cm thickness packaging enclosures respectively. The decrease in log reductions was not significantly (P > 0.05) affected by film thickness. No significant difference (P > 0.05) in E. coli O157:H7 decontamination efficacy between packaged and unpackaged Romaine lettuce was observed due to PL treatment. The initial total aerobic bacteria and mold and yeast populations were also reduced significantly (P < 0.05) by >1 log, due to the treatment. Overall, the results of this work demonstrate that PL treatment may be used to enhance microbial safety and reduce post processing contamination of packaged Romaine lettuce.

Human volunteer study of the decontamination of chemically contaminated hair and the consequences for systemic exposure

The decontamination of exposed persons is a priority following the release of toxic chemicals. Efficacious decontamination reduces the risk of harm to those directly affected and prevents the uncontrolled spread of contamination. Human studies examining the effectiveness of emergency decontamination procedures have primarily focused on decontaminating skin, with few examining the decontamination of hair and scalp. We report the outcome of two studies designed to evaluate the efficacy of current United Kingdom (UK) improvised, interim and specialist mass casualty decontamination protocols when conducted in sequence. Decontamination efficacy was evaluated using two chemical simulants, methyl salicylate (MeS) and benzyl salicylate (BeS) applied to and recovered from the hair of volunteers. Twenty-four-hour urinary MeS and BeS were measured as a surrogate for systemic bioavailability. Current UK decontamination methods performed in sequence were partially effective at removing MeS and BeS from hair and underlying scalp. BeS and MeS levels in urine indicated that decontamination had no significant effect on systemic exposure raising important considerations with respect to the speed of decontamination. The decontamination of hair may therefore be challenging for first responders, requiring careful management of exposed persons following decontamination. Further work to extend these studies is required with a broader range of chemical simulants, a larger group of volunteers and at different intervention times.

Decontamination of Polymeric Surgical Sutures Covered with Bacterial Biofilms Using Nonthermal Plasma

The objective of the study was to investigate the bactericidal effectiveness of atmospheric pressure nonthermal plasma (NTP) on biofilms of Staphylococcus aureus and Escherichia coli formed on the surface of surgical sutures. Tests were carried out for polyamide nonabsorbable monofilament sutures and mid-term absorbable synthetic monofilament sutures made of glyconate. Dielectric barrier discharge reactor providing atmospheric air plasma and constant discharge power density of 70 mW/cm2 was used in the experiments. The colonization/decontamination efficacy was quantified by colony-counting assay. It was shown that decontamination efficacy of the studied surgical sutures was time-dependent i.e. the effect was more visible for longer exposure times ranging from 60 to 360 s. It was proposed to combine plasma treatment with washing the biofilms with a phosphate buffered saline to to allow the plasma to interact with cells in the deeper layers of bacterial biofilm. The application of the original method of treatment of biofilms was more effective than the separate plasma treatment. As a result, the lethal effect was most often achieved after 300 s regardless of the type of suture and biofilm. The results of the comparative studies on the decontamination efficiency of polymeric surgical suture surface by disinfectants and NTP technique have shown unequivocally that plasma treatment is the most effective way to deactivate bacterial cells and ensures a lethal effect for most of the tested cases.

Calcium, magnesium and aluminium ions as decontaminating agents against dermal fluoride absorption following hydrofluoric acid exposure

The fluoride ions of the industrially largely irreplaceable, locally corrosive hydrofluoric acid (HF) can scavenge cations in biological tissues, which explains their high toxic potential, and also leads to local acidification through proton release. The influence of three complexing agents, calcium (Ca2+) gluconate (as 2.5% Ca2+gel and individually (2.84%) or commercially (10%) formulated Ca2+solution), magnesium (Mg2+) gluconate (2.84%) solution and aluminium (Al3+) solution (Hexafluorine®, pure and diluted) on the absorption of fluoride following HF exposure (1–3 min, 100 μl, 30%/0.64 cm2) through human skin was investigated in an ex-vivo diffusion cell model. Fluoride absorption was assessed over 6–24 h and analysed with a fluoride electrode. Decreasing the contamination time reduced the fluoride absorption distinctly which was further reduced by the application of fluoride-binding decontamination agents (Ca2+, Mg2+, Al3+) or water alone without being significantly different. Ca2+ appeared slightly more effective than Mg2+ in reducing fluoride absorption. Moreover, the addition of pH adjusting buffer promoted the decontamination efficacy. Fluoride-binding agents can facilitate the decontamination of dermal HF exposure. However, prompt decontamination appeared to be the key to successful limitation of fluoride absorption and pushes the choice of decontamination agent almost into the background.

Inactivation of Shiga toxin-producing Escherichia coli O157: H7 and mesophilic background microbiota of meat homogenate using elevated hydrostatic pressure, mild heat, and thymol.

A six-strain mixture of E. coli O157:H7 was exposed to 0 to 9 min of six treatments: (i) hydrostatic pressure (400MPa) at 4°C; (ii) hydrostatic pressure and thymol at 4°C; (iii) thymol at 4°C; (iv) heat at 40°C; (v) hydrostatic pressure at 40°C; and (vi) hydrostatic pressure and thymol at 40°C. Pressure intensity level of 400MPa and thymol concentration of 0.15% (w/v) were used for the experiments of inoculated pathogen (4.0 to 5.0 log CFU/mL) in a homogenate (10% nonsterilized beef in 90% sterilized distilled water). Temperature was precisely monitored by stainless steel water jacket surrounding pressure chamber (16mL volume), mechanically linked to a refrigerated circulating water bath. Analyses of variance were conducted followed by Tukey- and Dunnett's-adjusted mean separations. Pathogen counts before treatment were 4.08±0.7log CFU/mL and were reduced (P <0.05) to 0.67±0.2log CFU/mL after 6 min of pressure treatment. Thymol and mild heat (40°C) further augmented decontamination efficacy of pressure treatments where in their presence, the mesophilic background microbiota counts of pressure-treated samples after 3, 6, and 9 min were reduced (P <0.05) by 2.1, 2.5, and 3.1 log CFU/mL, respectively. Results of the current study indicate that thymol and mild heat could enhance decontamination efficacy of elevated hydrostatic pressure for pasteurization of food commodities. This could be of great significance for industry practitioners to assure microbiological safety of a product and cost optimization by benefiting from synergism of antimicrobials, mild heat, and elevated hydrostatic pressure. PRACTICAL APPLICATION: Thymol and mild heat could enhance decontamination efficacy of pressure-based pasteurizer that could be of great significance for practitioners. Application of pressure coupled with antimicrobial and mild heat could assure microbiological safety of a product, lead to cost optimization, and assist in meeting regulatory requirements of food commerce such as Hazard Analysis and Critical Control Point and Preventive Control for Human Food rule of Food Safety Modernization Act. Addition of an antimicrobial could have further co-benefits for the product due to residual protective effects during shelf-life and minimizing potential undesirable organoleptic changes associated with pressure treatments of >400MPa.

Potential Surrogates for Evaluation of Decontamination Methods Under Field Study Conditions or BSL-2 Biosecurity Lab Conditions: A Review

Surrogate species are commonly used to evaluate the ability of decontamination, sterilization, and/or disinfectant methods to sanitize bio-contaminated surfaces, equipment, facilities, soil, or water. As new decontamination technologies become commercialized there is an ongoing need to evaluate them using field studies, or on-site for large, stationary systems, to determine if they are more environmentally friendly, less expensive, or more effective than the current sanitation practices. This surrogate review compares potential surrogate species such as MS2 bacteriophage, Clostridium difficile, Bacillus subtilis, and Cytisus scoparius for their ability to accurately estimate the efficacy of decontamination, sterilization methods or commercial systems when evaluated under field conditions. Evaluation of decontamination systems, using field or on-site studies conducted under real-world conditions provides realistic estimates of sanitation and insights into potential risks to health or the environment. Multi-stage decontamination systems, or semi-sterilization methods, such as concentrated, or high-level, disinfectants, pressure washing equipment with steam, or extended ultra-violet (UV-C) radiation, require hard-to-kill surrogates, such as B. subtilis, to determine effective treatments. Use of multiple surrogates for decontamination or sterilization research alleviates several concerns about selecting a single surrogate species that may only perform well only under specific treatments or environmental conditions.

Significance of implant design on the efficacy of different peri-implantitis decontamination protocols.

To assess the efficacy of three mechanical decontamination methods in four types of commercially available implants. Ninety-six implants of four commercial brands with different designs (regarding thread depth and thread pitch) were soaked in a surrogate biofilm (ink) and air-dried. Circumferential standardized peri-implant defects with 6mm in depth and 1.55mm in width were custom-made with a 3D printer. Stained implants were inserted in the defects and instrumented with three different methods: a titanium brush (TNB), a metallic ultrasonic tip (IST) and an air abrasive (PF). Standardized photographs were taken vertically to the implant axis (flat view), and with angulations of 60° (upper view) and 120° (lower view) to the implant long axis. The percentage of residual stain (PRS) was calculated with the image analysis software. Scanning electron microscope evaluations were performed on the buccal aspect of the implants at the central level of the defect. The efficacy of PF was significantly inferior to the TNB and IST in all implant designs, while there were no significant differences between TNB and IST. IST showed significantly higher PRS in the implant with the highest thread pitch, while the TNB had the highest PRS in the implant with a marked reverse buttress-thread design. The micro-thread design had the lowest values of PRS for all decontamination methods. The apically facing threads represented the areas with highest PRS for all implant designs and decontamination methods. Thread geometry influenced the access of the decontamination devices and in turn its efficacy. Implants with lower thread pitch and thread depth values appeared to have less residual staining. Clinicians must be aware of the importance of thread geometry in the decontamination efficacy.

Penetration of fission product ions into complex solids and the effect of ionic wash methods.

During washing of radiologically impacted building surfaces, penetration of radionuclide ions into complex solids associated with these surfaces may occur. This study investigates the penetration of 137Cs, 85Sr, and 152Eu solutions into numerous common building materials and radionuclide behavior when these materials were exposed to a static bath or low-pressure flow of tap water, 0.1 M potassium chloride (KCl), and 0.5 M KCl. The decontamination efficacy and the depth profile for residual contamination were measured to determine the conditions under which applying a wash solution has benefit compared to physically removing the surface material. On asphalt, 70-80% of the radionuclides were found to be within 0.02 mm of the surface. Concrete is more porous than asphalt, and 80% of the radionuclides were within 0.2 mm of the surface for 137Cs and 152Eu and 50-80% for 85Sr. Water effectively removed all contaminants from hard nonporous surfaces. Finally, this paper illustrates that a wash penalty factor concept-defined as ratio of the depth at which 50% of the radioactivity is found in the washed sample divided by the depth at which 50% of radioactivity is found in the control-can serve as a way to quantify whether the wash method increases the depth at which contamination penetrates into the material and thus the material becomes more difficult to decontaminate.

High-pressure and thermal-assisted pasteurization of habituated, wild-type, and pressure-stressed Listeria monocytogenes, Listeria innocua, and Staphylococcus aureus

Current study investigated decontamination efficacy of elevated hydrostatic pressure against wild-type, 72-h habituated, and pressure-stressed phenotypes of Listeria monocytogenes, Listeria innocua, and Staphylococcus aureus in milk and orange juice. Pressure intensity levels of 350 and 500 MPa were utilized at 4.4 °C and 60.0 °C for up to 7 min. Temperature was controlled using a stainless steel water jacket surrounding reaction chamber connected to a refrigerated circulating water bath. Results were statistically analyzed using ANOVA. While <2 log reduction of L. monocytogenes, L. innocua, and S. aureus were observed after treatments of up to 7 min at 500 MPa at 4.4 °C, same treatment at 60.0 °C resulted in ≥5 log reductions (p < 0.05) of pathogens in milk. Similar trends were observed when the pathogens were inoculated in acidic environment of orange juice and treated at 350 MPa at 4.4 and 60 °C. As such, under the conditions of our experiments, we observed that mild heat could to great extend augment the efficacy of a pressure-based pasteurization treatment. The three phenotypes (habituated, wild-type, and pressure-stressed) of these Gram-positive pathogens exhibited comparable sensitivity to treatments, indicating a validated treatment against wild-type cells could be as efficacious against other phenotypes as well.

Emerging techniques in food science: the resistance of chlorpyrifos pesticide pollution against arc and dielectric barrier discharge plasma

Many studies introduced cold plasma as a novel and effective processing technology for microbial decontamination of food and water as well as for the removal of environmental pollution such as pesticide. However, as there are several types of plasma designs, their efficacy in degrading major pesticide residues, such as chlorpyrifos (as a hazardous chemical), should be explored. This study was conducted to assess the decontamination efficacy of 8 min of arc and dielectric barrier discharge (DBD) plasma on chlorpyrifos pesticide-water samples at a con-centration of 2 mg·L-1. The plasma-treated samples were assessed by liquid chromatography-mass spectrometry (LC-MS) and compared with the control (untreated) sample. In addition, the effects of plasma processes on some physical properties of samples were studied. According to the results, plasma-treated samples showed similar physical characteristics (e.g., refractive index and color values) to those of the untreated samples. While the temperature of the samples remained steady during the DBD plasma treatment, arc plasma changed the temperature of the sample at a rate of about 3.75°C·min–1 and yielded a sample with a final temperature of 60°C. However, contrary to the general belief that plasma is an efficient technique for pesticide degradation, chemical analyses showed high resistance of chlorpyrifos against both arc and DBD plasma under the conditions used in the present study. Therefore, the possibility of high resistance of pesticide pollution to this emerging technology should be considered. Also, further studies on the efficiency of the selected plasma system for removing pesticide pollution (e.g., during water and wastewater treatment) at industrial scale is needed.

Antimicrobial Efficacy of Acidified Peroxyacetic Acid Treatments Against Surrogates for Enteric Pathogens on Prerigor Beef

Two studies were conducted to evaluate the antimicrobial effects of pH-adjusted solutions of peroxyacetic acid (PAA) against nonpathogenic Escherichia coli surrogates for Shiga toxin–producing E. coli and Salmonella, inoculated on beef. In both studies, prerigor beef carcass surface tissue (10 × 10 cm pieces) was inoculated (6–7 log colony-forming units [CFU]/cm2) on the adipose side with a 5-strain mixture of E. coli biotype I. In the first study, samples were left untreated (control) or were immersed (10 s) in solutions of PAA (300 parts per million [ppm]) acidified with a sulfuric acid and sodium sulfate blend (SSS) (pH 1.2) or PAA (400 ppm) acidified with acetic acid (2%), citric acid (1%), lactic acid (3.5%), or SSS (pH 1.2 or pH 1.8). In the second study, samples were left untreated or were spray treated (10 s) using a spray cabinet, with water, PAA (350 ppm or 400 ppm), PAA (350 ppm or 400 ppm) acidified with SSS (pH 1.2), or PAA (400 ppm) acidified with acetic acid (2%). All immersion treatments effectively (P &amp;lt; 0.05) reduced inoculated E. coli populations (6.2 log CFU/cm2) by 2.3 to 2.8 log CFU/cm2. When the test solutions were applied by spraying, the water and all PAA-containing treatments lowered inoculated populations (6.4 log CFU/cm2) by 0.4 (P ≥ 0.05) and 1.7–1.9 (P &amp;lt; 0.05) log CFU/cm2, respectively. No (P ≥ 0.05) differences in decontamination efficacy were observed between the 5 PAA-containing spray treatments. Overall, the results showed that PAA and the pH-adjusted PAA treatments were effective in reducing levels of the surrogates for Shiga toxin–producing E. coli and Salmonella. Although no differences in antimicrobial efficacy were noted between the nonacidified and acidified PAA treatments immediately after treatment application, further studies are needed to evaluate how the acidified PAA treatments perform as part of a sequential multi-hurdle decontamination strategy to reduce pathogen contamination on beef carcasses.

Effects of threat and efficacy messages on expected adherence to decontamination protocols in an immersive simulated chemical incident: A randomized controlled experiment

AbstractThe UK’s Initial Operational Response (IOR) decontamination protocol requires that chemically contaminated casualties remove contaminated clothing (disrobe) and then apply water or absorbent materials to skin. The health‐protective efficacy of the protocol is predicated on casualties quickly accepting both the need to act and the fact that this protocol is an effective action. The aim of this study was to test whether adherence is affected by the presentation of information by first responders about the severity and likelihood of contamination (Threat) and the health‐protective efficacy of IOR procedures (efficacy). A double‐blind randomized controlled experiment (N = 132) with a 3x2 independent measures design (registration number: ISRCTN17886859) was used to assess the effects of threat and efficacy on behavioural expectations during a simulated chemical incident, presented as an immersive video. Results indicated that addressing the threat of contamination made participants more likely to expect themselves to disrobe were the situation real. Emphasizing the efficacy of protective action made participants more likely to expect themselves to apply absorbent materials to skin and had an indirect positive effect on disrobing expectations, mediated by efficacy perceptions. We recommend that first responders explicitly address the threat of contamination and efficacy of decontamination when communicating with chemically contaminated casualties.

In vitro and in vivo genotoxicity assessment of ferric ferrocyanide and potassium-cobalt ferrocyanide

Ferric hexacyanoferrate(II) (Fe4[Fe(CN)6]3), i.e. Prussian blue (PB) has been used for many years to remove from the body the two toxic isotopes of cesium and thallium following irradiation.Recently, potassium cobalt hexacyanoferrate(II) (K2COFe(CN)6), which has shown a better efficacy for decontamination, is also being considered for use to enhance the elimination of cesium isotopes. In view to its preclinical and clinical development, in vitro and in vivo GLP-compliant genotoxicity studies were carried out on this product as well as on PB for comparison. Several tests dissecting the main events leading to genotoxicity, i.e. mutagenicity and chromosomal aberrations, both structural and quantitative were implemented.In vitro, no mutagenic effect was observed in the Ames test but both compounds were positive in the mouse lymphoma assay on TK locus and induced clastogenic effects in the in vitro chromosomal aberrations test on human lymphocytes, either in absence or in presence of metabolic activation.K-Co-ferrocyanide was also assayed in vivo in the mouse bone marrow micronucleus assay and PB was assessed for DNA fragmentation in the rodent Comet assay in both glandular stomach and colon. In the in vivo micronucleus mouse bone marrow, K-Co-ferrocyanide did not display any genotoxic activity up to 2000 mg/kg/d (x2) by oral route. In opposite, PB induced a significant increase in DNA fragmentation both in the glandular stomach and in the colon of rat treated 3 times with intake ranging from 2000 to 500 mg/kg. PB should be considered as an in vivo mutagen as well as Potassium cobalt hexacyanoferrate(II) since the in vitro genotoxicity profiles of both ferrocyanides are quite similar.Their use as cesium/ thallium decontamination agents in human should be assessed following a benefit/risk approach to enable a robust decision-making.

Multicycle Autoclave Decontamination of N95 Filtering Facepiece Respirators.

Introduction:During pandemic situations like the one caused by the emergent coronavirus SARS-CoV-2, healthcare systems face the challenge of limited personal protective equipment and impaired supply chains. This problem poses a threat to healthcare workers, first responders, and the public, which demands solutions that can span the gap between institutional shortages and resupplies.Objectives:To examine the efficacy of autoclave-based decontamination for the reuse of single-use surgical masks and N95 filtering facepiece respirators (FFRs). This method is the most readily available form of decontamination in the hospital and laboratory settings.Methods:Three models of N95 FFRs and two procedural masks were evaluated in this study. A moist heat autoclave using four different autoclave cycles: 115°C for one hour, 121.1°C for 30 minutes, 130°C for two minutes, and 130°C for four minutes was used. After the autoclave process, the FFRs were NIOSH fit tested and particle counting was performed for both coarse particles of 5 micrometers (µM) and fine particles from 0.1µM to 1.0µM.Results:We observed negligible alterations in the functionality and integrity of 3M 1805 and 3M 1870/1870+ N95 FFRs after three autoclave cycles. Surgical masks also showed minimal changes in functionality and integrity. The 3M 1860 FFR failed fit test after a single autoclave decontamination cycle.Discussion and Conclusion:The study finds that specific surgical masks and N95 FFR models can withstand autoclave decontamination for up to three cycles. Additionally, the autoclave cycles tested were those that could be readily achieved by both clinical and research institutions.

Hurdle Effect of Hot Air Impingement Drying and Surfactant-Sanitizer Wash on Removal of Listeria innocua from Fresh Apples

This study investigated the decontamination efficacy of washing treatments for whole fresh apples by using washes containing surfactants, lauric arginate, sodium dodecyl sulfate, and Tween 20, combined with peracetic acid (PAA), followed by hot air impingement drying. Whole fresh apples of selected varieties (Gala and Granny Smith) were inoculated with Listeria innocua (7 log CFU/mL) by using a dipping method, and then dried and subjected to wash treatments with selected washing solutions (H2O, PAA, PAA-lauric arginate, PAA-sodium dodecyl sulfate, and PAA-Tween 20), followed by hot air impingement drying at two different temperature and time conditions, 93°C for 60 s or 121°C for 25 s. The H2O and PAA wash followed by hot air impingement drying led to a maximum 1.5-log reduction of L. innocua on the fruit surface. Adding surfactants increased the effectiveness of washing and drying treatments, resulting in an approximate 2.2-log reduction. Surfactants increased the spreadability and evaporation rate of the washing solutions. Posttreatment changes in apple firmness were assessed during a 21-day storage at 4 and 21°C. The hot air impingement drying had no adverse effect on the firmness of the apples and did not show any further reduction in L. innocua. Washing apples with solutions containing surfactants combined with PAA followed by hot air impingement drying helped to reduce the microbial loads to some extent and may help to reduce drying times significantly.

Optimization of subsampling, decontamination, and DNA extraction of difficult peat and silt permafrost samples

This study aims to act as a methodological guide for contamination monitoring, decontamination, and DNA extraction for peaty and silty permafrost samples with low biomass or difficult to extract DNA. We applied a biological tracer, either only in the field or both in the field and in the lab, via either spraying or painting. Spraying in the field followed by painting in the lab resulted in a uniform layer of the tracer on the core sections. A combination of bleaching, washing, and scraping resulted in complete removal of the tracer leaving sufficient material for DNA extraction, while other widely used decontamination methods did not remove all detectable tracer. In addition, of four widely used commercially available DNA extraction kits, only a modified ZymoBIOMICS DNA Microprep kit was able to acquire PCR amplifiable DNA. Permafrost chemical parameters, age, and soil texture did not have an effect on decontamination efficacy; however, the permafrost type did influence DNA extraction. Based on these findings, we developed recommendations for permafrost researchers to acquire contaminant-free DNA from permafrost with low biomass.

Evaluation of the efficacy of a self-cleaning automated compounding system for the decontamination of cytotoxic drugs.

IntroductionLow surface contamination levels of hazardous drugs in compounding areas can be used as indicators of exposure and efficacy of cleaning procedures. We report the efficacy results of the KIRO® Oncology self-cleaning automated compounding system for decontamination of cytotoxic drugs, assessed in an oncology health center using a sanitizing method and an alkaline method.MethodsThe study was conducted for six-days over a three-week period. A mixture with known levels of 5-fluorouracil, ifosfamide, cyclophosphamide, gemcitabine, etoposide, methotrexate, paclitaxel, docetaxel and carboplatin was added to the KIRO® Oncology’s compounding area surface before each self-cleaning method was used. Contamination levels were determined, with a surface wipe sampling kit, at the end of the self-cleaning process.ResultsBackground surface contamination for quantified levels of cytotoxic drugs during routine use of KIRO® Oncology was below limit of quantification (<LOQ) for all drugs, except for carboplatin, which has a very low LOQ (0.2 ng/sample). The quantified drug levels detected on surface wipe samples after self-cleaning using both methods in the KIRO® Oncology’s compounding area surface sections were all <LOQ when spiking with 1 ng/cm2 (ten times the ‘safe’ reference value), except for carboplatin (alkaline method only), although its levels were still below the ‘safe’ reference value (0.1 ng/cm2). For surface contamination levels when spiking with 100 ng/cm2, both self-cleaning methods had decontamination efficacies >99.8% for all cytotoxic drugs analyzed.ConclusionThis study provides evidence on the efficacy of the KIRO® Oncology automatic self-cleaning system for surface area decontamination during the preparation of cytotoxic drugs.

The role of textiles as fomites in the healthcare environment: a review of the infection control risk.

BackgroundInfectious diseases are a significant threat in both healthcare and community settings. Healthcare associated infections (HCAIs) in particular are a leading cause of complications during hospitalisation. Contamination of the healthcare environment is recognised as a source of infectious disease yet the significance of porous surfaces including healthcare textiles as fomites is not well understood. It is currently assumed there is little infection risk from textiles due to a lack of direct epidemiological evidence. Decontamination of healthcare textiles is achieved with heat and/or detergents by commercial or in-house laundering with the exception of healthcare worker uniforms which are laundered domestically in some countries. The emergence of the COVID-19 pandemic has increased the need for rigorous infection control including effective decontamination of potential fomites in the healthcare environment. This article aims to review the evidence for the role of textiles in the transmission of infection, outline current procedures for laundering healthcare textiles and review studies evaluating the decontamination efficacy of domestic and industrial laundering.MethodologyPubmed, Google Scholar and Web of Science were searched for publications pertaining to the survival and transmission of microorganisms on textiles with a particular focus on the healthcare environment.ResultsA number of studies indicate that microorganisms survive on textiles for extended periods of time and can transfer on to skin and other surfaces suggesting it is biologically plausible that HCAIs and other infectious diseases can be transmitted directly through contact with contaminated textiles. Accordingly, there are a number of case studies that link small outbreaks with inadequate laundering or infection control processes surrounding healthcare laundry. Studies have also demonstrated the survival of potential pathogens during laundering of healthcare textiles, which may increase the risk of infection supporting the data published on specific outbreak case studies.ConclusionsThere are no large-scale epidemiological studies demonstrating a direct link between HCAIs and contaminated textiles yet evidence of outbreaks from published case studies should not be disregarded. Adequate microbial decontamination of linen and infection control procedures during laundering are required to minimise the risk of infection from healthcare textiles. Domestic laundering of healthcare worker uniforms is a particular concern due to the lack of control and monitoring of decontamination, offering a route for potential pathogens to enter the clinical environment. Industrial laundering of healthcare worker uniforms provides greater assurances of adequate decontamination compared to domestic laundering, due to the ability to monitor laundering parameters; this is of particular importance during the COVID-19 pandemic to minimise any risk of SARS-CoV-2 transmission.