Can you locate the scientific question in this article? A Low-Temperature Decontamination with Hydrogen Peroxide or Chlorine Dioxide for Space Applications (1).pdf - Adobe Acrobat Reader DC (32-bit)O XFile Edit View Sign Window HelpHomeToolsWorkshop 1.2 Scien..Workshop 1.1 Scien.Low-Temperature D... xSign In1 / 6100%Search 'Edit Text'I AĒMExport PDFJournals ASM.orgLow-Temperature Decontamination with Hydrogen Peroxide orChlorine Dioxide for Space ApplicationsAdobe Export PDFConvert PDF Files to Wordor Excel OnlineT. Pottage, S. Macken, K. Giri,* J. T. Walker, and A. M. BennettSelect PDF FileBiosafety Unit, Health Protection Agency, Microbiological Services Division, Porton Down, Salisbury, United KingdomLow-Temper.ns (1).pdfThe currently used microbial decontamination method for spacecraft and components uses dry-heat microbial reduction attemperatures of 110°C for extended periods to prevent the contamination of extraplanetary destinations. This process is effec-tive and reproducible, but it is also long and costly and precludes the use of heat-labile materials. The need for an alternative todry-heat microbial reduction has been identified by space agencies. Investigations assessing the biological efficacy of two gaseousdecontamination technologies, vapor hydrogen peroxide (Steris) and chlorine dioxide (ClorDiSys), were undertaken in a 20-m3exposure chamber. Five spore-forming Bacillus spp. were exposed on stainless steel coupons to vaporized hydrogen peroxideand chlorine dioxide gas. Exposure for 20 min to vapor hydrogen peroxide resulted in 6- and 5-log reductions in the recovery ofBacillus atrophaeus and Geobacillus stearothermophilus, respectively. However, in comparison, chlorine dioxide required anexposure period of 60 min to reduce both B. atrophaeus and G. stearothermophilus by 5 logs. Of the three other Bacillus spp.tested, Bacillus thuringiensis proved the most resistant to hydrogen peroxide and chlorine dioxide with D values of 175.4 s and6.6 h, respectively. Both low-temperature decontamination technologies proved effective at reducing the Bacillus spp. testedwithin the exposure ranges by over 5 logs, with the exception of B. thuringiensis, which was more resistant to both technologies.These results indicate that a review of the indicator organism choice and loading could provide a more appropriate and realisticchallenge for the sterilization procedures used in the space industry.Convert toMicrosoft Word (*.docx)Document Language:English (U.S.) ChangeConvertW;|hen a spacecraft visits regions of the solar system which maypotentially hold biological interest, Planetary Protection(1967 Outer Space Treaty) precautions must be observed to pro-tect any present and future life detection activities (2). Planetaryprotection precautions require that flight systems must be assem-baseline contamination level to be calculated which must be con-Edit PDFtrolled and reduced by a decontamination process.rocess used in thespace industry is dry-heat microbial reduction (DHMR) (14),which has been used on spacecraft and their components since thebled, tested, and launched under conditions to control the for- Viking lander missions in 1975. The spacecraft and componentsare heated to 110°C within a sealed dry oven for extended peri-ods of time (e.g., up to 50 h for one cycle) (8, 40). This method hasprovided effective and repeatable decontamination which hasbeen validated using thermocouples and biological indicator(s)(BI). The kinetics of heat inactivation of microorganisms is wellestablished and therefore demonstrates a high degree of sterilityThe current validated decontaminationConvert, edit and e-sign PDFforms & agreementsward contamination of pristine extraterrestrial environments byterrestrial microorganisms and indeed backward contaminationduring Earth return missions.Spacecraft and their components are constructed and assem-bled in high classification clean room facilities (30, 38) similar toFree 7-Day Trial8.12 x 10.88 inthat used in medical (12, 16, 42) and industrial pharmaceuticalDownloaded from http://aem.asm.org/ on April 29, 202 A Low-Temperature Decontamination with Hydrogen Peroxide or Chlorine Dioxide for Space Applications (1).pdf - Adobe Acrobat Reader DC (32-bit)O XFile Edit View Sign Window HelpHomeToolsWorkshop 1.2 Scien..Workshop 1.1 Scien.Low-Temperature D... xSign In1 / 6100%Search 'Edit Text'W|hen a spacecraft visits regions of the solar system which maypotentially hold biological interest, Planetary Protection(1967 Outer Space Treaty) precautions must be observed to pro-tect any present and future life detection activities (2). Planetaryprotection precautions require that flight systems must be assem-bled, tested, and launched under conditions to control the for-baseline contamination level to be calculated which must be con-trolled and reduced by a decontamination process.The current validated decontamination process used in thespace industry is dry-heat microbial reduction (DHMR) (14),which has been used on spacecraft and their components since theViking lander missions in 1975. The spacecraft and componentsare heated to 110°C within a sealed dry oven for extended peri-ods of time (e.g., up to 50 h for one cycle) (8, 40). This method hasprovided effective and repeatable decontamination which hasbeen validated using thermocouples and biological indicator(s)(BI). The kinetics of heat inactivation of microorganisms is wellestablished and therefore demonstrates a high degree of sterilityLO Export PDFAdobe Export PDFward contamination of pristine extraterrestrial environments byterrestrial microorganisms and indeed backward contaminationduring Earth return missions.Spacecraft and their components are constructed and assem-bled in high classification clean room facilities (30, 38) similar tothat used in medical (12, 16, 42) and industrial pharmaceutical(31) applications. Although it might be expected that the contam-inating organisms of these facilities will be the result of humanactivity (30), the highly desiccated and nutrient-limited environ-ment of spacecraft assembly clean rooms demonstrate selectivepressure toward oligotrophic organisms that can persist in theenvironment (30). Of these organisms, spore-forming bacteria areperhaps the best suited to persistence and survival (21, 26). Forexample, spore-forming Bacillus species are the most commonlyisolated (26), but other aerobic and anaerobic bacterial species validated low-temperature methods that would enable both largerhave also been detected, namely, Staphylococcus, Acinetobacter,Micrococcus, Clostridium, and Streptococcus spp. (36–38), as wellas eukaryotic organisms such as yeasts and fungi (37). The con-tinual microbial monitoring of the spacecraft assembly cleanrooms has led to the characterization of two new Bacillus species:Bacillus odysseyi (27) and Bacillus nealsonii (41).Since microorganisms that survive within spacecraft assemblyfacilities can potentially contaminate spacecraft components andthus ultimately their destinations, the bioburden needs to be re-duced to safe levels to satisfy the tightly regulated Planetary Pro-tection requirements before deployment (2). This cannot be doneby sterile manufacture alone. Regular assays of spacecraft allows aConvert PDF Files to Wordor Excel OnlineSelect PDF Fileassurance.Low-Temper.ns (1).pdfThe use of heat-sensitive components such as used on the Bea-gle 2 Lander ruled out the use of DHMR, and so alternative tech-nologies such as sporicides, gamma irradiation, and gas plasma (8,11, 32) were used. These technologies had to be accompanied byevidence of their efficacy to fulfill National Aeronautics and SpaceAdministration (NASA) requirements for this mission (32); themethods were not validated for continued use in the space indus-try. There has been much interest in developing alternative andConvert toMicrosoft Word (*.docx)Document Language:English (U.S.) Changemodules and small components to be decontaminated. Suchmethods must operate at a low temperature (

Question

Can you locate the scientific question in this article? A Low-Temperature Decontamination with Hydrogen Peroxide or Chlorine Dioxide for Space Applications (1).pdf - Adobe Acrobat Reader DC (32-bit)O XFile Edit View Sign Window HelpHomeToolsWorkshop 1.2 Scien..Workshop 1.1 Scien.Low-Temperature D... xSign In1 / 6100%Search 'Edit Text'I AĒMExport PDFJournals ASM.orgLow-Temperature Decontamination with Hydrogen Peroxide orChlorine Dioxide for Space ApplicationsAdobe Export PDFConvert PDF Files to Wordor Excel OnlineT. Pottage, S. Macken, K. Giri,* J. T. Walker, and A. M. BennettSelect PDF FileBiosafety Unit, Health Protection Agency, Microbiological Services Division, Porton Down, Salisbury, United KingdomLow-Temper.ns (1).pdfThe currently used microbial decontamination method for spacecraft and components uses dry-heat microbial reduction attemperatures of >110°C for extended periods to prevent the contamination of extraplanetary destinations. This process is effec-tive and reproducible, but it is also long and costly and precludes the use of heat-labile materials. The need for an alternative todry-heat microbial reduction has been identified by space agencies. Investigations assessing the biological efficacy of two gaseousdecontamination technologies, vapor hydrogen peroxide (Steris) and chlorine dioxide (ClorDiSys), were undertaken in a 20-m3exposure chamber. Five spore-forming Bacillus spp. were exposed on stainless steel coupons to vaporized hydrogen peroxideand chlorine dioxide gas. Exposure for 20 min to vapor hydrogen peroxide resulted in 6- and 5-log reductions in the recovery ofBacillus atrophaeus and Geobacillus stearothermophilus, respectively. However, in comparison, chlorine dioxide required anexposure period of 60 min to reduce both B. atrophaeus and G. stearothermophilus by 5 logs. Of the three other Bacillus spp.tested, Bacillus thuringiensis proved the most resistant to hydrogen peroxide and chlorine dioxide with D values of 175.4 s and6.6 h, respectively. Both low-temperature decontamination technologies proved effective at reducing the Bacillus spp. testedwithin the exposure ranges by over 5 logs, with the exception of B. thuringiensis, which was more resistant to both technologies.These results indicate that a review of the indicator organism choice and loading could provide a more appropriate and realisticchallenge for the sterilization procedures used in the space industry.Convert toMicrosoft Word (*.docx)Document Language:English (U.S.) ChangeConvertW;|hen a spacecraft visits regions of the solar system which maypotentially hold biological interest, Planetary Protection(1967 Outer Space Treaty) precautions must be observed to pro-tect any present and future life detection activities (2). Planetaryprotection precautions require that flight systems must be assem-baseline contamination level to be calculated which must be con-Edit PDFtrolled and reduced by a decontamination process.rocess used in thespace industry is dry-heat microbial reduction (DHMR) (14),which has been used on spacecraft and their components since thebled, tested, and launched under conditions to control the for- Viking lander missions in 1975. The spacecraft and componentsare heated to >110°C within a sealed dry oven for extended peri-ods of time (e.g., up to 50 h for one cycle) (8, 40). This method hasprovided effective and repeatable decontamination which hasbeen validated using thermocouples and biological indicator(s)(BI). The kinetics of heat inactivation of microorganisms is wellestablished and therefore demonstrates a high degree of sterilityThe current validated decontaminationConvert, edit and e-sign PDFforms & agreementsward contamination of pristine extraterrestrial environments byterrestrial microorganisms and indeed backward contaminationduring Earth return missions.Spacecraft and their components are constructed and assem-bled in high classification clean room facilities (30, 38) similar toFree 7-Day Trial8.12 x 10.88 inthat used in medical (12, 16, 42) and industrial pharmaceuticalDownloaded from http://aem.asm.org/ on April 29, 202 A Low-Temperature Decontamination with Hydrogen Peroxide or Chlorine Dioxide for Space Applications (1).pdf - Adobe Acrobat Reader DC (32-bit)O XFile Edit View Sign Window HelpHomeToolsWorkshop 1.2 Scien..Workshop 1.1 Scien.Low-Temperature D... xSign In1 / 6100%Search 'Edit Text'W|hen a spacecraft visits regions of the solar system which maypotentially hold biological interest, Planetary Protection(1967 Outer Space Treaty) precautions must be observed to pro-tect any present and future life detection activities (2). Planetaryprotection precautions require that flight systems must be assem-bled, tested, and launched under conditions to control the for-baseline contamination level to be calculated which must be con-trolled and reduced by a decontamination process.The current validated decontamination process used in thespace industry is dry-heat microbial reduction (DHMR) (14),which has been used on spacecraft and their components since theViking lander missions in 1975. The spacecraft and componentsare heated to >110°C within a sealed dry oven for extended peri-ods of time (e.g., up to 50 h for one cycle) (8, 40). This method hasprovided effective and repeatable decontamination which hasbeen validated using thermocouples and biological indicator(s)(BI). The kinetics of heat inactivation of microorganisms is wellestablished and therefore demonstrates a high degree of sterilityLO Export PDFAdobe Export PDFward contamination of pristine extraterrestrial environments byterrestrial microorganisms and indeed backward contaminationduring Earth return missions.Spacecraft and their components are constructed and assem-bled in high classification clean room facilities (30, 38) similar tothat used in medical (12, 16, 42) and industrial pharmaceutical(31) applications. Although it might be expected that the contam-inating organisms of these facilities will be the result of humanactivity (30), the highly desiccated and nutrient-limited environ-ment of spacecraft assembly clean rooms demonstrate selectivepressure toward oligotrophic organisms that can persist in theenvironment (30). Of these organisms, spore-forming bacteria areperhaps the best suited to persistence and survival (21, 26). Forexample, spore-forming Bacillus species are the most commonlyisolated (26), but other aerobic and anaerobic bacterial species validated low-temperature methods that would enable both largerhave also been detected, namely, Staphylococcus, Acinetobacter,Micrococcus, Clostridium, and Streptococcus spp. (36–38), as wellas eukaryotic organisms such as yeasts and fungi (37). The con-tinual microbial monitoring of the spacecraft assembly cleanrooms has led to the characterization of two new Bacillus species:Bacillus odysseyi (27) and Bacillus nealsonii (41).Since microorganisms that survive within spacecraft assemblyfacilities can potentially contaminate spacecraft components andthus ultimately their destinations, the bioburden needs to be re-duced to safe levels to satisfy the tightly regulated Planetary Pro-tection requirements before deployment (2). This cannot be doneby sterile manufacture alone. Regular assays of spacecraft allows aConvert PDF Files to Wordor Excel OnlineSelect PDF Fileassurance.Low-Temper.ns (1).pdfThe use of heat-sensitive components such as used on the Bea-gle 2 Lander ruled out the use of DHMR, and so alternative tech-nologies such as sporicides, gamma irradiation, and gas plasma (8,11, 32) were used. These technologies had to be accompanied byevidence of their efficacy to fulfill National Aeronautics and SpaceAdministration (NASA) requirements for this mission (32); themethods were not validated for continued use in the space indus-try. There has been much interest in developing alternative andConvert toMicrosoft Word (*.docx)Document Language:English (U.S.) Changemodules and small components to be decontaminated. Suchmethods must operate at a low temperature (<60°C), be compat-ible with a number of different materials used within the spaceConvertReceived 5 January 2012 Accepted 28 March 2012Published ahead of print 6 April 2012Address correspondence to T. Pottage, thomas.pottage@hpa.org.uk.Edit PDF* Present address: Biocon, Electronics City, Bangalore, India.Copyright © 2012, American Society for Microbiology. All Rights Reserved.doi:10.1128/AEM.07948-11Convert, edit and e-sign PDFforms & agreementsJune 2012 Volume 78 Number 12Applied and Environmental Microbiology p. 4169-4174aem.asm.org 4169Free 7-Day Trial* aem.asm.org/ on April 29, 2021 at Carleton Univ

Accepted Answer

Low temperature contamination shall be done with Hydrogen Peroxide or with  Chlorine dioxide for…