Sample holding time is defined as the duration a sample can be stored after collection and before analysis without affecting the results.
Sample holding time is critical in microbiological testing because microorganisms are living entities that multiply, die, or change in concentration over time.
๐๐ก๐ ๐๐๐ฌ๐ข๐ ๐ฉ๐ซ๐ข๐ง๐๐ข๐ฉ๐ฅ๐ ๐ข๐ฌ ๐ฌ๐ข๐ฆ๐ฉ๐ฅ๐:
A microbiological sample should be tested within the defined holding time and under the specified storage conditions to ensure the test result remains representative of the sample at the time of collection.
๐๐ก๐ ๐๐๐๐๐ฉ๐ญ๐๐๐ฅ๐ ๐ก๐จ๐ฅ๐๐ข๐ง๐ ๐ญ๐ข๐ฆ๐ ๐ข๐ฌ ๐ง๐จ๐ญ ๐ง๐๐๐๐ฌ๐ฌ๐๐ซ๐ข๐ฅ๐ฒ ๐ญ๐ก๐ ๐ฌ๐๐ฆ๐ ๐๐จ๐ซ ๐๐ฏ๐๐ซ๐ฒ ๐ญ๐ฒ๐ฉ๐ ๐จ๐ ๐ฌ๐๐ฆ๐ฉ๐ฅ๐.
It may depend on:
- Sample type
- Test method
- Microorganisms of interest
- Storage temperature
- Container
- Sample matrix
- Test purpose
- Validated or scientifically justified procedures
๐๐ก๐ฒ ๐๐จ๐๐ฌ ๐๐จ๐ฅ๐๐ข๐ง๐ ๐๐ข๐ฆ๐ ๐๐๐ญ๐ญ๐๐ซ?
After a sample is collected, its microbial population may change.
- Microorganisms May Multiply
- Microorganisms May Die
- Microbial Composition May Change
๐๐ก๐ฒ ๐๐ฌ ๐๐ก๐ข๐ฌ ๐๐ฆ๐ฉ๐จ๐ซ๐ญ๐๐ง๐ญ ๐๐จ๐ซ ๐๐ก๐๐ซ๐ฆ๐๐๐๐ฎ๐ญ๐ข๐๐๐ฅ ๐๐ข๐๐ซ๐จ๐๐ข๐จ๐ฅ๐จ๐ ๐ฒ?
Sample holding time can influence the reliability of microbiological results.
This is particularly important when results are used to assess:
- Pharmaceutical water quality
- Raw materials
- In-process materials
- Finished products
- Bioburden
- Microbial limits
- Environmental samples
An unreliable result may lead to unnecessary investigations or, more importantly, an incorrect assessment of product or process quality.
