Low-Temperature Decontamination with Hydrogen Peroxide or Chlorine Dioxide for Space Applications

ABSTRACTThe currently used microbial decontamination method for spacecraft and components uses dry-heat microbial reduction at temperatures of >110°C for extended periods to prevent the contamination of extraplanetary destinations. This process is effective and reproducible, but it is also long and costly and precludes the use of heat-labile materials. The need for an alternative to dry-heat microbial reduction has been identified by space agencies. Investigations assessing the biological efficacy of two gaseous decontamination technologies, vapor hydrogen peroxide (Steris) and chlorine dioxide (ClorDiSys), were undertaken in a 20-m3exposure chamber. Five spore-formingBacillusspp. were exposed on stainless steel coupons to vaporized hydrogen peroxide and chlorine dioxide gas. Exposure for 20 min to vapor hydrogen peroxide resulted in 6- and 5-log reductions in the recovery ofBacillus atrophaeusandGeobacillus stearothermophilus, respectively. However, in comparison, chlorine dioxide required an exposure period of 60 min to reduce bothB. atrophaeusandG. stearothermophilusby 5 logs. Of the three otherBacillusspp. tested,Bacillus thuringiensisproved the most resistant to hydrogen peroxide and chlorine dioxide with D values of 175.4 s and 6.6 h, respectively. Both low-temperature decontamination technologies proved effective at reducing theBacillusspp. tested within the exposure ranges by over 5 logs, with the exception ofB. 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 realistic challenge for the sterilization procedures used in the space industry.

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Evaluation of Chlorine Dioxide Gas Treatment To Inactivate Salmonella enterica on Mungbean Sprouts†

Journal of Food Protection ◽

10.4315/0362-028x.jfp-13-407 ◽

2014 ◽

Vol 77 (11) ◽

pp. 1876-1881 ◽

Cited By ~ 14

Author(s):

VARA PRODDUK ◽

BASSAM A. ANNOUS ◽

LINSHU LIU ◽

KIT L. YAM

Keyword(s):

Chlorine Dioxide ◽

Safety Concern ◽

Microbial Reduction ◽

Bacterial Attachment ◽

Mechanical Mixing ◽

Microscopy Imaging ◽

Gas Treatment ◽

Chlorine Dioxide Gas ◽

Gaseous Chlorine Dioxide ◽

The Difference

Although freshly sprouted beans and grains are considered to be a source of nutrients, they have been associated with foodborne outbreaks. Sprouts provide good matrices for microbial localization and growth due to optimal conditions of temperature and humidity while sprouting. Also, the lack of a kill step postsprouting is a major safety concern. The objective of this work was to evaluate the effectiveness of chlorine dioxide gas treatment to reduce Salmonella on artificially inoculated mungbean sprouts. The effectiveness of gaseous chlorine dioxide (0.5 mg/liter of air) with or without tumbling (mechanical mixing) was compared with an aqueous chlorine (200 ppm) wash treatment. Tumbling the inoculated sprouts during the chlorine dioxide gas application for 15, 30, and 60 min reduced Salmonella populations by 3.0, 4.0, and 5.5 log CFU/g, respectively, as compared with 3.0, 3.0, and 4.0 log CFU/g reductions obtained without tumbling, respectively. A 2.0 log CFU/g reduction in Salmonella was achieved with an aqueous chlorine wash. The difference in microbial reduction between chlorine dioxide gas versus aqueous chlorine wash points to the important role of surface topography, pore structure, bacterial attachment, and/or biofilm formation on sprouts. These data suggested that chlorine dioxide gas was capable of penetrating and inactivating cells that are attached to inaccessible sites and/or are within biofilms on the sprout surface as compared with an aqueous chlorine wash. Consequently, scanning electron microscopy imaging indicated that chlorine dioxide gas treatment was capable of penetrating and inactivating cells attached to inaccessible sites and within biofilms on the sprout surfaces.

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Microbial reduction field model for the table egg with chlorine dioxide gas

Journal of Preventive Veterinary Medicine ◽

10.13041/jpvm.2020.44.1.33 ◽

2020 ◽

Vol 44 (1) ◽

pp. 33-39

Author(s):

Dong-Hoon Myeong ◽

◽

Han-Sung Chung ◽

Kyoung-Ju Song ◽

Seoung-Jun Kim ◽

...

Keyword(s):

Chlorine Dioxide ◽

Field Model ◽

Microbial Reduction ◽

Chlorine Dioxide Gas

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Inactivation of foodborne pathogens on alfalfa and radish seeds by sequential treatment with chlorine dioxide gas and dry heat

Food Control ◽

10.1016/j.foodcont.2017.08.016 ◽

2018 ◽

Vol 85 ◽

pp. 253-258 ◽

Cited By ~ 3

Author(s):

Sang-Hyun Park ◽

Jun-Bae Ahn ◽

Dong-Hyun Kang

Keyword(s):

Chlorine Dioxide ◽

Foodborne Pathogens ◽

Sequential Treatment ◽

Chlorine Dioxide Gas ◽

Dry Heat

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Use of different non-chemical methods for the management of adult Callosobruchus maculatus (F.) (Coleoptera: Bruchidae) in stored chickpea

Journal of Bio-Science ◽

10.3329/jbs.v23i0.37468 ◽

2018 ◽

Vol 23 ◽

pp. 57-65

Author(s):

SHA Mahdi ◽

M Hasan ◽

I Mahfuz ◽

M Khalequzzaman

Keyword(s):

Low Temperature ◽

Uv Radiation ◽

Callosobruchus Maculatus ◽

Exposure Period ◽

Temperature Treatment ◽

Physical Factors ◽

Dry Heat ◽

Low Temperature Treatment ◽

Plant Powders ◽

Parthenium Weed

The efficiency of physical factors (dry heat, low temperature and UV-radiation), leaf powders of Neem (Azadirachta indica A. Juss.), Bichuti (Flacourtia indica Merr.) and Parthenium weed (Parthenium hysterophorus L.) and two insecticides (Salvo and Amithrin plus) was evaluated against Callosobruchus maculatus (F.). For dry heat treatment, the calculated LD50 values for C. maculatus were 56.92, 54.26, 52.27, 50.76, 49.09, 50.55 and 29.59°C after 50, 60, 70, and 80 minutes, 24, 36, 48 h of treatment respectively, and the LD50 values were 58.61 and 5.18°C at 1 and 2 h for low temperature treatment respectively. LT50 values of the treatment of UV-radiation were 48.63, 29.89, 17.54, 11.11, 5.93 and 1.35 °C for the exposure period of 24, 36, 48, 60, 72 and 48 h respectively. The calculated LD50 values of leaf powder were 3.38, 3.15, 2.88, 2.45 and 2.40 mg cm-2 for A. indica, 3.91, 3.80, 3.55, 3.30, and 3.08 for F. indica, 12.11, 4.35, 1.86, 1.49, and 1.36 for P. hysterophorus after 12, 24, 36, 48 and 60 h of treatment respectively. The calculated LD50 values were 0.64, 0.33, 0.23, 0.04 and 0.008 mg cm-2 for Salvo and 0.35, 0.23, 0.09, 0.08 and 0.01 mg cm-2 for Amithrin plus at 12, 24, 36, 48 and 60 h respectively. The order of effectiveness of physical factors was dry heat >low temperature >UV-radiation. On the other hand, the order of toxicity of plant powders was F. indica >A. indica >P. hysterophorus. In case of insecticides it was Amithrin plus >Salvo. The findings suggest that physical factors and plant leaf powders can be used in integration with other bio rational approaches.J. bio-sci. 23: 57-65, 2015

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Control of Legionella Contamination and Risk of Corrosion in Hospital Water Networks following Various Disinfection Procedures

Applied and Environmental Microbiology ◽

10.1128/aem.03873-15 ◽

2016 ◽

Vol 82 (10) ◽

pp. 2959-2965 ◽

Cited By ~ 13

Author(s):

Isabella Marchesi ◽

Greta Ferranti ◽

Antonella Mansi ◽

Anna M. Marcelloni ◽

Anna R. Proietto ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Chlorine Dioxide ◽

Legionella Pneumophila ◽

Water Networks ◽

Promising Alternative ◽

Content Type ◽

Hydrogen Peroxide Treatment ◽

Temperature Levels ◽

Physical And Chemical ◽

Chemical Disinfection

ABSTRACTPhysical and chemical disinfection methods have been proposed with the aim of controllingLegionellawater contamination. To date, the most effective procedures for reducing bacterial contamination have not yet been defined. The aim of this study was to assess the long-term effectiveness of various disinfection procedures in order to reduce both culturable and nonculturable (NC) legionellae in different hospital water networks treated with heat, chlorine dioxide, monochloramine, and hydrogen peroxide. The temperature levels and biocide concentrations that proved to give reliable results were analyzed. In order to study the possible effects on the water pipes, we verified the extent of corrosion on experimental coupons after applying each method for 6 months. The percentage of positive points was at its lowest after treatment with monochloramine, followed by chlorine dioxide, hydrogen peroxide, and hyperthermia. Different selections ofLegionellaspp. were observed, as networks treated with chlorine-based disinfectants were contaminated mainly byLegionella pneumophilaserogroup 1, hyperthermia was associated with serogroups 2 to 14, and hydrogen peroxide treatment was associated mainly with non-pneumophilaspecies. NC cells were detected only in heat-treated waters, and also when the temperature was approximately 60°C. The corrosion rates of the coupons were within a satisfactory limit for water networks, but the morphologies differed. We confirm here that chemical disinfection controlsLegionellacolonization more effectively than hyperthermia does. Monochloramine was the most effective treatment, while hydrogen peroxide may be a promising alternative to chlorine-based disinfectants due to its ability to select for other, less virulent or nonpathogenic species.

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Vapor hydrogen peroxide as alternative to dry heat microbial reduction

Advances in Space Research ◽

10.1016/j.asr.2008.01.005 ◽

2008 ◽

Vol 42 (6) ◽

pp. 1150-1160 ◽

Cited By ~ 22

Author(s):

S. Chung ◽

R. Kern ◽

R. Koukol ◽

J. Barengoltz ◽

H. Cash

Keyword(s):

Hydrogen Peroxide ◽

Microbial Reduction ◽

Dry Heat

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Development of Combined Dry Heat and Chlorine Dioxide Gas Treatment with Mechanical Mixing for Inactivation of Salmonella enterica Serovar Montevideo on Mung Bean Seeds†

Journal of Food Protection ◽

10.4315/0362-028x.jfp-14-422 ◽

2015 ◽

Vol 78 (5) ◽

pp. 868-872 ◽

Cited By ~ 12

Author(s):

BASSAM A. ANNOUS ◽

ANGELA BURKE

Keyword(s):

Chlorine Dioxide ◽

Mung Bean ◽

Safety Concern ◽

Combined Treatment ◽

Hot Water ◽

Mechanical Mixing ◽

Gas Treatment ◽

Chlorine Dioxide Gas ◽

Dry Heat ◽

Complete Inactivation

Foodborne outbreaks have been associated with the consumption of fresh sprouted beans. The sprouting conditions of mung bean seeds provide optimal conditions of temperature and relative humidity for any potential pathogenic contaminant on the seeds to grow. The lack of a kill step postsprouting is a major safety concern. Thus, the use of a kill step on the seeds prior to a sprouting step would enhance the safety of fresh sprouts. The objective of this work was to evaluate the effectiveness of the combined thermal and chlorine dioxide gas (3.5 mg/liter of air) treatment with mechanical mixing (tumbling) to eliminate Salmonella on artificially inoculated mung bean seeds. Although no viable Salmonella was recovered from seeds treated in hot water at 60°C for 2 h, these treated seeds failed to germinate. Dry heat treatments (55, 60, or 70°C) for up to 8 h reduced Salmonella populations in excess of 3 log CFU/g. The use of tumbling, while treating the seeds, resulted in up to 1.6 log CFU/g reduction in Salmonella populations compared with no tumbling. Dry heat treatment at 65°C for 18 h with tumbling resulted in a complete inactivation of Salmonella populations on inoculated seeds with low inoculum levels (2.83 log CFU/g) as compared with high inoculum levels (4.75 log CFU/g). The increased reductions in pathogenic populations on the seeds with the use of tumbling could be attributed to increased uniformity of heat transfer and exposure to chlorine dioxide gas. All treated seeds were capable of germinating, as well as the nontreated controls. These results suggest that this combined treatment would be a viable process for enhancing the safety of fresh sprouts.

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Bleaching optimization at WestRock mill in Covington, Virginia

TAPPI Journal ◽

10.32964/tj15.9.581 ◽

2016 ◽

Vol 15 (9) ◽

pp. 581-586 ◽

Cited By ~ 1

Author(s):

RICARDO B. SANTOS ◽

PETER W. HART ◽

DOUGLAS C. PRYKE ◽

JOHN VANDERHEIDE

Keyword(s):

Hydrogen Peroxide ◽

Sodium Hydroxide ◽

Chlorine Dioxide ◽

Capital Expenditures ◽

Equipment Repair ◽

Optimization Program ◽

Hardwood Pulp ◽

Improved Performance

The WestRock mill in Covington, VA, USA, initiated a long term diagnostic and optimization program for all three of its bleaching lines. Benchmarking studies were used to help identify optimization opportunities. Capital expenditures for mixing improvement, filtrate changes, equipment repair, other equipment changes, and species changes were outside the scope of this work. This focus of this paper is the B line, producing southern hardwood pulp in a D(EP)DD sequence at 88% GE brightness. The benchmarking study and optimization work identified the following opportunities for improved performance: nonoptimal addition of caustic and hydrogen peroxide to the (EP) stage, carryover of D0 filtrate to the (EP) stage, and carryover of (EP) filtrate to the D1 stage. As a result of actions the mill undertook to address these opportunities, D0 kappa factor decreased about 5%, sodium hydroxide consumption in the (EP) stage decreased about 35%, chlorine dioxide consumption in the D1 stage decreased about 25%, and overall bleaching cost decreased about 15%.

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