Botanical extracts are agricultural products that have been dried, milled, and packed. Microbial load is a normal quality parameter, and the specification should state the limits and methods that apply to your market and product category.
How the method works
What it can prove
- Whether the lot meets the agreed microbiological limits at release.
- The presence or absence of specific indicator organisms.
- A baseline for monitoring storage and transport conditions.
Where it stops
- A release result is a snapshot, not a shelf-life guarantee.
- Different methods and sample sizes are not directly comparable.
- Does not establish absence of every pathogen.
The standard panel
A typical panel includes total aerobic plate count (TPC), yeast and mould count, Escherichia coli, and Salmonella. Some buyers add Staphylococcus aureus, Listeria, or Enterobacteriaceae depending on the matrix and the market. Results are reported as colony-forming units per gram (CFU/g) or as absence in a defined sample size.
Methods are usually based on ISO or pharmacopoeial standards, with specific media, incubation temperatures, and confirmation steps. The certificate should state the method, the sample size, and the limit for each parameter.
What affects the result
Sampling, storage, and laboratory handling can all change the count. A lot that was tested soon after production may behave differently after months in a warehouse. If microbial stability matters for your application, ask for historical data and storage recommendations, not only a single release result.
Irradiation, ethylene oxide, and other microbial reduction treatments are regulated differently across markets. If a supplier uses a treatment, it should be declared and supported by the appropriate documentation.
Reading the result on a COA
- Check the method, sample size, and limit for each parameter.
- Ask whether the result is a release test or a stability test.
- Confirm the storage conditions assumed by the specification.
What to ask a supplier
Which methods and limits were used for each parameter?
Was the sample taken from the finished lot or from a blend?
Can you provide historical data for this grade?
Related terms
References and further reading
External links are provided for orientation. Methods, limits, and acceptance criteria differ by market and product; confirm the applicable requirements with your regulatory advisor.
Cite this page
Rainwood Botanical. "Microbiological testing for botanical extracts." October 2026. https://ingredients.rainwoodbio.com/resources/methods/microbiology/