1.1本规程涵盖了用于检测和计数具有运动粘度的液体燃料中异养细菌（HPC）和真菌的膜过滤器（MF）程序 ≤ 24毫米 2. ·s -1 在环境温度下。 1.2本定量实践主要来自IP方法385 和试验方法 D5259 . 1.3本试验可在现场或实验室进行。 1.4单个微生物在特定生长介质上形成菌落的能力取决于待枚举微生物的分类和生理状态、生长介质的化学成分和培养条件。因此，测试结果不应解释为绝对值。相反，根据指南，它们应被用作包括其他测试参数的诊断或状态监测工作的一部分 D6469 . 1.5本规程提供了将燃料样品微生物输送至滤膜的替代方案、过滤的体积或稀释液、用于培养燃料微生物的生长介质和培养温度。这种灵活性旨在促进诊断工作。当此实践用作状态监测程序的一部分时，应始终使用单个程序。 1.6以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.7 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全和健康实践，并确定监管限制的适用性。 ====意义和用途====== 5.1感染燃料系统的生物杀灭微生物通常在系统表面或燃料-水界面上积聚的煤泥中最为丰富（指南 D6469 ). 然而，从燃料系统内的这些位置获取样本通常是不切实际的。虽然从燃料相样本中回收的活菌和真菌数量可能比水相样本中的活菌和真菌数量小几个数量级，但燃料相生物体通常是最容易获得的燃料和燃料系统微生物污染指标。 5.2 生长介质选择性- 指导 E1326 讨论了生长培养基选择的局限性。任何选择的培养基都有利于某些物种的菌落形成，而抑制其他物种的菌落形成。 如中所述 6.3 ，物理、化学和生理变量会影响活细胞计数测试结果。试验方法 D7463 提供了一种量化燃料和燃料相关水中微生物生物量的非培养方法。 5.3由于可以通过膜过滤技术（试验方法）分析各种样品尺寸或其稀释度 D5259 和 F1094 )，测试灵敏度可以根据样本中预期的总体密度进行调整。 5.4枚举数据应作为诊断工作或常规状况监测程序的一部分。枚举数据不应用作燃料质量标准。

1.1 This practice covers a membrane filter (MF) procedure for the detection and enumeration of Heterotrophic bacteria (HPC) and fungi in liquid fuels with kinematic viscosities ≤ 24 mm 2 · s -1 at ambient temperature. 1.2 This quantitative practice is drawn largely from IP Method 385 and Test Method D5259 . 1.3 This test may be performed either in the field or in the laboratory. 1.4 The ability of individual microbes to form colonies on specific growth media depends on the taxonomy and physiological state of the microbes to be enumerated, the chemistry of the growth medium, and incubation conditions. Consequently, test results should not be interpreted as absolute values. Rather they should be used as part of a diagnostic or condition monitoring effort that includes other test parameters, in accordance with Guide D6469 . 1.5 This practice offers alternative options for delivering fuel sample microbes to the filter membrane, volumes or dilutions filtered, growth media used to cultivate fuel-borne microbes, and incubation temperatures. This flexibility is offered to facilitate diagnostic efforts. When this practice is used as part of a condition monitoring program, a single procedure should be used consistently. 1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.7 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 and health practices and determine the applicability of regulatory limitations prior to use. ====== Significance And Use ====== 5.1 Biodeteriogenic microbes infecting fuel systems typically are most abundant within slime accumulations on system surfaces or at the fuel-water interface (Guide D6469 ). However, it is often impractical to obtain samples from these locations within fuel systems. Although the numbers of viable bacteria and fungi recovered from fuel-phase samples are likely to be several orders of magnitude smaller than those found in water-phase samples, fuel-phase organisms are often the most readily available indicators of fuel and fuel system microbial contamination. 5.2 Growth Medium Selectivity— Guide E1326 discusses the limitations of growth medium selection. Any medium selected will favor colony formation by some species and suppress colony formation by others. As noted in 6.3 , physical, chemical and physiological variables can affect viable cell enumeration test results. Test Method D7463 provides a non-culture means of quantifying microbial biomass in fuels and fuel associated water. 5.3 Since a wide range of sample sizes, or dilutions thereof, can be analyzed by the membrane filter technique (Test Methods D5259 and F1094 ), the test sensitivity can be adjusted for the population density expected in the sample. 5.4 Enumeration data should be used as part of diagnostic efforts or routine condition monitoring programs. Enumeration data should not be used as fuel quality criteria.