ASTM E3178-26

1.1 This practice is used to quantify the efficacy of liquid or solid decontaminants on Bacillus spores dried on the surface of coupons made from porous and non-porous materials. Distinguish between bactericidal and bacteriostatic chemicals within decontamination mixtures. This is important because many decontaminants contain both reactive compounds and high concentrations of bacteriostatic surfactants.

All test samples are directly compared to pre-neutralized controls, un-inoculated negative growth controls, and solution controls on the same day as the test to increase practical confidence in the inactivation data. Practices E1054 describes practices for decontaminant neutralization.

1.2 This practice should be performed only by those trained in microbiological techniques, are familiar with antimicrobial (sporicidal) agents and the application instructions of the antimicrobial products.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

5.1 The practice can be used to evaluate coupon materials of any composition, insofar as the coupon can be prepared small enough to fit inside filter units mentioned in 4.1.

5.2 This practice defines procedures that are quantitative, scalable, rapid, sensitive, and safe, while minimizing labor and addressing statistical confidence (1-3).

• 5.2.1 Quantitative— The total number of spores per coupon is determined by dilution-plating, and all spores remaining on the coupon are assayed for activity in the extraction tube to provide confidence that all the spores were accounted for.
• 5.2.2 Statistical Confidence— The use of five independent preparations of spore inocula for a statistical n of 5.
• 5.2.3 Sensitivity— Allows for complete detection of all culturable spores inoculated on a coupon, including the spores that remain attached to the coupon.
• 5.2.3.1 The limit of detection is dependent on the culturability of fully matured spores to germinate, outgrow, and divide in the presence of the extraction medium (1 % tryptic soy broth, 100 mM L-Alanine, 1 mM inosine) or on tryptic soy agar, or both.
• 5.2.3.2 Published data indicated that these media, combined with the test temperatures and conditions described herein, will generate results with a high level of practical confidence for detecting culturable Bacillus spores (4).
• 5.2.4 Safety— Inoculated coupons are contained within filter units.
• 5.2.5 Simplicity of Testing— Tests and extractions are performed in the same filter unit to minimize coupon handling steps.
• 5.2.6 Scalable and Rapid— A maximum of 36 samples can be processed in 1 h by two technicians; a total of 300 samples have been processed by six technicians in 5 h (1, 2).
• 5.2.7 Wide application for numerous Bacillus species and strains. The method has also been modified and used for vegetative bacteria and viruses as well (1, 2).