Evaluation of Penicylinders Used in Disinfectant Testing: Bacterial Attachment and Surface Texture

1987 ◽  
Vol 70 (5) ◽  
pp. 903-906
Author(s):  
Eugene C Cole ◽  
William A Rutala ◽  
Johnny L Carson
Keyword(s):  
Stainless Steel ◽  
Surface Texture ◽  
Environmental Protection Agency ◽  
Bacterial Attachment ◽  
Dilution Method ◽  
Bacterial Inoculation ◽  
Protection Agency ◽  
Smooth Numbers ◽  
Salmonella Choleraesuis ◽  
Aoac Method

Abstract Two passible deficiencies in the AOAC use-dilution method for registration of chemical disinfectants by the Environmental Protection Agency are examined: (7) the physical disparities among brands of penicylinders and (2) the variability of bacterial numbers on penicylinders depending upon test strain and penicylinder surface texture. Textual differences of 2 brands of stainless steel penicylinders, one brand of porcelain, and one brand of glass were assessed by scanning electron microscopy. A considerable variation in smoothness of both inner and outer surfaces of stainless steel and porcelain penicylinders was observed. Glass penicylinders were very smooth. Numbers of bacteria attached to a penicylinder were assessed by vortexing the penicylinders 30 s at No. 4 after using the AOAC method of bacterial inoculation and drying 40 min at 37°C. With this methodology, stainless steel carriers retained the 3 AOAC-recommended bacterial test strains differentially: ca 107 for Pseudomonas aeruginosa, 5 x 106 tat Staphylococcus aureus, and 106 for Salmonella choleraesuis; glass retained 10'-107 organisms of all 3 test strains; porcelain retained about that amount of S. aureus but 105-106 P. aeruginosa and 103-104 S. choleraesuis. These data suggest that disinfectants are not similarly challenged with the AOAC-recommended test bacteria and that an alternative method should be considered to ensure comparable numbers of bacteria on penicylinders

Should the AOAC Use-Dilution Method Be Continued for Regulatory Purposes?

2012 ◽  
Vol 95 (2) ◽  
pp. 406-410
Author(s):  
Navid Omidbakhsh
Keyword(s):  
Statistical Analysis ◽  
Environmental Protection ◽  
Bactericidal Activity ◽  
Environmental Protection Agency ◽  
Dilution Method ◽  
Protection Agency ◽  
Current Trends ◽  
Actual Evaluation ◽  
Qualitative Nature ◽  
The U.S

Abstract Despite its very poor reproducibility, AOAC INTERNATIONAL's use-dilution method (UDM) for bactericidal activity (AOAC Methods 964.02, 955.14, and 955.15) has been required by the U.S. Environmental Protection Agency (EPA) since 1953 for regulatory purposes, while methods with better reproducibility have been adopted in Canada and Australia. This study reviews UDM from a statistical perspective. Additionally, the test's expected results were compared to those obtained from actual evaluation of several formulations. Significant gaps have been identified in the reproducibility of the test data as predicted by statistical analysis and those presented to the EPA for product registration. UDM's poor reproducibility, along with its qualitative nature, requires the concentration of the active ingredient to be high enough to ensure all or most carriers to be free of any viable organisms. This is not in accord with the current trends towards sustainability, human safety, and environmental protection. It is recommended that the use of the method for regulatory purposes be phased out as soon as possible, and methods with better design and reproducibility be adopted instead.

Bacterial Numbers on Penicylinders Used in Disinfectant Testing: Use of 24 Hour Adjusted Broth Cultures

1988 ◽  
Vol 71 (1) ◽  
pp. 9-11
Author(s):  
Eugene C Cole ◽  
William A Rutala
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Stainless Steel ◽  
Bacterial Attachment ◽  
Broth Culture ◽  
Relative Efficacy ◽  
Salmonella Choleraesuis ◽  
Growth Studies ◽  
Cell Densities ◽  
Disinfectant Efficacy

Abstract The current AOAC use-dilution methods of disinfectant efficacy testing require the use of 48-54 h unadjusted broth cultures of Salmonella choleraesuis, Staphylococcus aureus, and Pseudomonas aeruginosa for the inoculation of stainless steel penicylinders. The use of unadjusted broth cultures contributes to noncomparable numbers of organisms on penicylinders among the test strains due to relative efficacy of bacterial attachment to penicylinders and to bacterial numbers in broth. To achieve comparable numbers of cells on the penicylinders among the 3 test strains, the cell densities of S. aureus and P. aeruginosa in broth culture were visually adjusted. Growth studies were conducted using S. choleraesuis and P. aeruginosa to determine the numbers of cells in broth at timed intervals and the corresponding numbers of cells attaching to the penicylinders. Results showed that the use of the 24 h broth cultures for all 3 test strains, with adjustment of S. aureus and P. aeruginosa broths, contributes to more comparable numbers of organisms attached to the penicylinders used in disinfectant testing.

Efficacité de huit désinfectants sur trois types de surfaces contaminées par Pseudomonas aeruginosa

1983 ◽  
Vol 29 (12) ◽  
pp. 1715-1730 ◽  
Author(s):  
P. Gélinas ◽  
J. Goulet
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Stainless Steel ◽  
Dilution Method ◽  
Surface Material ◽  
Extracellular Material ◽  
Aoac Method ◽  
Chemical Products ◽  
Plastic Surfaces ◽  
Number Of Bacteria ◽  
Scanning Electron

The disinfecting capacity of eight commercial chemical products was evaluated by the use–dilution method given by the Association of Official Analytical Chemists (AOAC) on three types of surface material (steel, aluminum, and plastic). For most products tested the limit concentration was 10 times higher for disinfecting aluminum and plastic surfaces man stainless steel. As observed on the scanning electron microscope, the number of bacteria deposited on the surface and the production of extracellular material on polypropylene by Pseudomonas aeruginosa ATCC 15442 would explain the observed differences. The applicability of the AOAC method or other techniques for the evaluation of the disinfecting capacity on different surfaces is discussed.

Quantitative Evaluation of Bacteria Washed from Stainless Steel Penicylinders During AOAC Use-Dilution Method

1988 ◽  
Vol 71 (5) ◽  
pp. 868-871
Author(s):  
Edith M Alfano ◽  
Eugene C Cole ◽  
William A Rut Ala
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Stainless Steel ◽  
Quaternary Ammonium ◽  
Dilution Method ◽  
Salmonella Choleraesuis ◽  
Dilution Water ◽  
Scanning Electron

Abstract Stainless steel penicylinders inoculated separately with test bacteria {Salmonella choleraesuis, Pseudomonas aeruginosa, or Staphylococcus aureus) are used in the AOAC use-dilution method (UDM) for disinfectant efficacy testing. Numbers of bacteria remaining on penicylinders were quantitatively assessed to determine if cells are washed from the penicylinders after a 10 min exposure to phosphate buffer dilution water (PBDW). Inoculated penicylinders were also examined by scanning electron microscopy (SEM) to determine the presence of cells remaining attached to the penicylinders after a 10 min exposure to a quaternary ammonium disinfectant and separately to PBDW. The percentage of cells washed from inoculated penicylinders exposed to PBDW was 89.9 for Salmonella choleraesuis, 48.8 for Pseudomonas aeruginosa, and 38.8 for Staphylococcus aureus. Qualitative examination of penicylinders by scanning electron microscopy confirmed the attachment of S. aureus and P. aeruginosa cells to penicylinders exposed separately to PBDW and a quaternary ammonium disinfectant. Few S. choleraesuis cells were observed on penicylinders exposed to PBDW and no cells were observed after disinfectant exposure. The variability of the numbers of viable cells entering the recovery media among the 3 UDM test bacteria due to cell detachment could be a significant factor in the recognized variability of the use-dilution method.

scholarly journals Enumeration Procedure for Monitoring Test Microbe Populations on Inoculated Carriers in AOAC Use-Dilution Methods

2006 ◽  
Vol 89 (6) ◽  
pp. 1629-1634 ◽  
Author(s):  
Stephen F Tomasino ◽  
Rebecca M Fiumara ◽  
Michele P Cottrill
Keyword(s):  
Environmental Protection Agency ◽  
Performance Standard ◽  
Dilution Method ◽  
Bacterial Cells ◽  
Mean Values ◽  
Test Culture ◽  
Monitoring Test ◽  
Aoac Method ◽  
Test Microbe

Abstract The AOAC Use-Dilution methods do not provide procedures to enumerate the test microbe on stainless steel carriers (penicylinders) or guidance on the expected target populations of the test microbe (i.e., a performance standard). This report describes the procedures used by the U.S. Environmental Protection Agency to enumerate the test microbe (carrier counts) associated with conducting the Use-Dilution method with Staphylococcus aureus (Method 955.15) and Pseudomonas aeruginosa (Method 964.02) and the examination of historical data. The carrier count procedure involves the random selection of carriers, shearing bacterial cells from the carrier surface through sonication, and plating of serially diluted inoculum on trypticase soy agar. For each Use-Dilution test conducted, the official AOAC method was strictly followed for carrier preparation, culture initiation, test culture preparation, and carrier inoculation steps. Carrier count data from 78 Use-Dilution tests conducted over a 6-year period were compiled and analyzed. A mean carrier count of 6.6 logs (approximately 4.0 × 106colony-forming units/carrier) was calculated for both S. aureus and P. aeruginosa. Of the mean values, 95% fell within ±2 repeatability standard deviations. The enumeration procedure and target carrier counts are desirable for standardizing the Use-Dilution methods, increasing their reproducibility, and ensuring the quality of the data.

Scanning electron microscopy of asbestos-containing material where the asbestos fibers are considered locked in a binder

1993 ◽  
Vol 51 ◽  
pp. 472-473
Author(s):  
J. R. Millette ◽  
R. S. Brown
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Environmental Protection Agency ◽  
Building Materials ◽  
The United States ◽  
Protection Agency ◽  
Asbestos Fibers ◽  
Different Types ◽  
Binder Material ◽  
Scanning Electron

The United States Environmental Protection Agency (EPA) has labeled as “friable” those building materials that are likely to readily release fibers. Friable materials when dry, can easily be crumbled, pulverized, or reduced to powder using hand pressure. Other asbestos containing building materials (ACBM) where the asbestos fibers are in a matrix of cement or bituminous or resinous binders are considered non-friable. However, when subjected to sanding, grinding, cutting or other forms of abrasion, these non-friable materials are to be treated as friable asbestos material. There has been a hypothesis that all raw asbestos fibers are encapsulated in solvents and binders and are not released as individual fibers if the material is cut or abraded. Examination of a number of different types of non-friable materials under the SEM show that after cutting or abrasion, tuffs or bundles of fibers are evident on the surfaces of the materials. When these tuffs or bundles are examined, they are shown to contain asbestos fibers which are free from binder material. These free fibers may be released into the air upon further cutting or abrasion.

Managing the impacts of mining on Ghana’s water resources from a legal perspective

2018 ◽  
Vol 1 (3) ◽  
pp. 156-165 ◽  
Author(s):  
Nasirudeen Abdul Fatawu
Keyword(s):  
Surface Water ◽  
Water Resources ◽  
Environmental Protection Agency ◽  
Large Scale ◽  
Small Scale ◽  
Mining Activities ◽  
Protection Agency ◽  
Environmental Laws ◽  
Mining Areas ◽  
Legal Perspective

Recent floods in Ghana are largely blamed on mining activities. Not only are lives lost through these floods, farms andproperties are destroyed as a result. Water resources are diverted, polluted and impounded upon by both large-scale minersand small-scale miners. Although these activities are largely blamed on behavioural attitudes that need to be changed, thereare legal dimensions that should be addressed as well. Coincidentally, a great proportion of the water resources of Ghana arewithin these mining areas thus the continual pollution of these surface water sources is a serious threat to the environmentand the development of the country as a whole. The environmental laws need to be oriented properly with adequate sanctionsto tackle the impacts mining has on water resources. The Environmental Impact Assessment (EIA) procedure needs to bestreamlined and undertaken by the Environmental Protection Agency (EPA) and not the company itself.

Short Communication: A Note of Caution to Users of ECOSAR

1999 ◽  
Vol 34 (1) ◽  
pp. 179-182 ◽  
Author(s):  
Klaus L.E. Kaiser ◽  
John C. Dearden ◽  
Werner Klein ◽  
T. Wayne Schultz
Keyword(s):  
Environmental Protection Agency ◽  
Partition Coefficients ◽  
Short Communication ◽  
Computer Software ◽  
Aquatic Organisms ◽  
Protection Agency ◽  
Personal Computer Software ◽  
Linear Correlations ◽  
Class Representative ◽  
Chemical Class

Abstract ECOSAR (1998), a personal computer software program available from the U.S. Environmental Protection Agency (EPA) and affiliated vendors, is used to estimate the toxicity of chemicals to aquatic organisms, particularly fish, daphnid and algae species. It relies on approximately 150 equations, each for a chemical class of substances (Clements et al. 1996), which are linear correlations (SARs) of measured toxicity values of class-representative compounds with their octanol/water partition coefficients, with the latter taken from a database or computed by a companion program.

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