What is the maximum hold time for total coliform samples without preservation?

The maximum hold time for total coliform samples without preservation is 30 hours. This time frame is important because, beyond this duration, the viability of the coliform bacteria may decrease, which can lead to inaccuracies in the monitoring and testing results. The analysis needs to reflect the true microbial content of the sample, and extending beyond this hold time can compromise the reliability of detecting the presence of total coliforms.

While some other options might also represent valid hold times for different types of analyses or parameters, the specific regulation and guidance around total coliform sampling emphasize that 30 hours is the standard maximum limit to ensure sample integrity and accurate testing results.