1.1 本试验方法涵盖了测试膜过滤器截留直径等于或略大于0.2µm孔径的细菌能力的程序。 1.2 所描述的程序供用户实验室使用，与制造商实验室不同。 1.3 以SI单位表示的值将被视为标准值。本标准不包括其他计量单位。 1.4 本标准并不旨在解决与其使用相关的所有安全性问题（如果有）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践并确定法规限制的适用性。 1.5 本国际标准是根据W发布的关于制定国际标准、指南和建议的原则的决定中确立的国际公认的标准化原则制定的世界贸易组织技术性贸易壁垒委员会。 ======意义和用途====== 5.1 使用膜过滤的微生物水测试程序基于这样的前提，即特定大小范围内的所有细菌将被所使用的膜过滤器保留。如果膜过滤器不能保留这些细菌，可能会出现假阴性结果或降低的密度估计，这可能会产生严重的影响，因为在被测试的水中，特别是在饮用水中存在未被识别的潜在健康危害。 5.1.1 设计的该程序将使用户能够测试每个膜过滤器批号保留等于或大于所述膜孔径的所有细菌的能力。 5.2 由于该膜通常用于灭菌不可高压灭菌的液体，因此该膜的保留特性必须稳定。

1.1 This test method covers a procedure to test membrane filters for their ability to retain bacteria whose diameter is equal to or slightly larger than the 0.2-µm pore size of the membrane filter. 1.2 The procedures described are for the use of user laboratories as differentiated from manufacturers’ laboratories. 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 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. ====== Significance And Use ====== 5.1 Microbiological water testing procedures using membrane filtration are based on the premise that all bacteria within a specific size range will be retained by the membrane filter used. If the membrane filter does not retain these bacteria, false negative results or lowered density estimates may occur that could have serious repercussions due to the presence of unrecognized potential health hazards in the water being tested, especially in drinking water. 5.1.1 This procedure as devised will enable the user to test each membrane filter lot number for its ability to retain all bacterial equal to, or larger than, the stated membrane pore size. 5.2 Since this membrane is often used to sterilize nonautoclavable liquids, it is essential that the retention characteristics of this membrane are stable.