What is the maximum holding time for fecal coliforms using the Fecal Coliform Procedure?

The maximum holding time for fecal coliforms using the Fecal Coliform Procedure is eight hours. This standard is established to ensure that samples remain viable and accurately represent the bacterial presence in water. Holding samples beyond this time frame may lead to changes in the microbial population, growth of non-fecal coliforms, or die-off of existing coliform bacteria, thereby compromising the reliability of test results.

Holding times are critical in microbiological testing because they can significantly affect the quantitative and qualitative results. The eight-hour limit provides a sufficient window to transport samples to a laboratory while maintaining the integrity of the sample for accurate analysis. It ensures that the conditions are optimized for detecting and enumerating fecal coliforms in the water sample, which is essential for assessing water quality and safety.