Pharma-grade psyllium is usually tested for total aerobic microbial count, total yeast and mould count, and the absence of specified pathogens such as E. coli and Salmonella. The exact limits come from the pharmacopoeia monograph or the product registration you rely on, not from the supplier.
Because limits and methods are revised, always work from the current edition and your own regulatory team. Do not copy figures from an old spec sheet.
The usual tests
- Total aerobic microbial count (TAMC), sometimes called total plate count.
- Total combined yeast and mould count (TYMC).
- Escherichia coli, usually required to be absent in a stated sample size.
- Salmonella, usually required to be absent in a stated sample size.
- Other organisms some buyers add, such as bile-tolerant gram-negative bacteria, Staphylococcus aureus or Pseudomonas aeruginosa.
Where the limits come from
In the US, the USP sets microbial testing methods in its general chapters, including <61> for microbial enumeration and <62> for specified microorganisms, and monographs set the acceptance criteria. The European Pharmacopoeia has equivalent general chapters and monographs for ispaghula. Your product's registration, or your customer's spec, may set tighter limits again.
Food supplements are often regulated as food rather than medicine, depending on the market. In that case the limits come from food law and your customer. For a wider view, see whether psyllium needs to meet USP or EP standards.
Counts are usually given in colony-forming units per gram. Pathogens are reported as absent or present in a set weight of sample. Make sure the units and sample sizes on the certificate match your spec.
Meeting the limits
Untreated husk can vary widely in microbial load. Many pharma buyers therefore require steam sterilised husk or powder. The treatment and its trade-offs are covered in whether psyllium needs sterilisation or irradiation.
Treatment is only half of it. Product can pick up microbes again after sterilisation if it is cooled, sifted or packed in a dirty area. Check that the plant keeps treated and untreated product apart.
Failures usually come from inconsistent sterilisation, moisture pick-up during storage, or certificates from a different lot. A certificate that always shows perfect results for every lot is a reason to ask questions. See how to know a lab report is genuine.
Testing that holds up
- Use the method in your pharmacopoeia, and name it in the contract.
- Test a representative sample of each lot, drawn by someone independent of the mill.
- Use an accredited lab and ask for the original report with the lab's reference number.
- Keep retained samples of each lot for retesting.
- Retest on arrival if your quality system requires it.
How Creston & Co handles this
We draw samples ourselves from the packed lot and send them to an NABL-accredited lab using the method in your spec. You receive the original report before the balance payment. Ask for a free sourcing review.