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Compendial Testing

Know the load before you sterilize.

A sterilization cycle is only validated against the bioburden you actually carry. We count it — aerobic bacteria, yeast and mold — on raw materials, in-process samples, water and finished units, and name anything worth naming.

USP <61>ISO 11737-1
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The number behind the cycle

Sterility assurance is arithmetic: a validated cycle delivers a defined log reduction, and that reduction is only sufficient relative to the load going in. If incoming bioburden drifts upward — a new supplier, a seasonal water change, a maintenance gap — the cycle that was adequate last quarter may not be adequate now. Routine bioburden monitoring is what turns that from a discovery into a trend line.

Recovery proven on your matrix

Counting is easy; counting correctly on a product that fights back is not. Preservatives, surfactants, alcohols and actives all suppress recovery, so method suitability comes first: we demonstrate that the neutralization and dilution scheme we use actually recovers a low-level challenge from your specific matrix. Only then do routine counts mean anything.

  • Pour plate, spread plate or membrane filtration, chosen for the matrix
  • Neutralization of preservatives and antimicrobial actives, validated per product
  • Bacterial and fungal counts incubated and read separately
  • Results reported as CFU per gram, per milliliter or per unit and trended over time

What you get back

  • Separate bacterial and fungal counts with the method and dilution scheme stated
  • Your method suitability report showing recovery is not suppressed by the matrix
  • Species identification on isolates of interest, added to your house flora library
  • Trending across submissions so a drift shows up as a slope, not a surprise
  • Data formatted to feed directly into your sterilization validation file
What's included

The scope of bioburden testing.

Total aerobic count (TAMC)

Aerobic bacterial load by pour plate, spread plate or membrane filtration.

Yeast & mold count (TYMC)

Combined yeast and mold count on fungal media, incubated and read separately.

Method suitability

Recovery verified on your matrix, including neutralization of preservatives and actives.

Water & utilities

Purified water, WFI and process water by membrane filtration, with alert and action trending.

Raw material & in-process

Incoming component screening and in-process sampling at the points that matter.

Isolate identification

MALDI-TOF genus and species ID on organisms of interest, built into your house flora library.

Common questions

Bioburden Testing, answered.

What is the difference between bioburden testing and microbial limits testing?
The counting methods overlap, but the questions differ. Bioburden asks how much microbial load a material carries — usually before sterilization, so a cycle can be validated against it. Microbial limits testing under USP <61> and <62> asks whether a non-sterile finished product sits inside its release specification and is free of specified organisms. Plenty of clients need both, at different points in the same process.
Do you neutralize preservatives and antimicrobial actives?
Yes, and we prove the neutralization works before reporting a single routine count. A preserved product tested without validated neutralization tends to produce reassuring low counts that mean nothing at all. Method suitability establishes the dilution and neutralization scheme for your specific matrix.
How much sample do I need to send?
Ten grams or ten milliliters per test is the usual starting point, which allows the standard dilution scheme with material to spare. Low-volume or high-value products can be scaled down — tell us what you have and we will design the scheme around it rather than turning the sample away.
Can you trend bioburden results over time?
That is most of the value. Every result lands in your portal alongside the previous ones, so incoming material, water and in-process points can be read as trend lines with your alert and action levels marked. A supplier change or a seasonal water shift shows up as a slope well before it shows up as a failure.
Do you test water systems?
Yes — purified water, water for injection and process water by membrane filtration, which is the appropriate method for the low counts these systems should be running. We can set up a routine sampling schedule across your loop points and trend each one separately.
Often run together

Related testing.

Microbial Limits Testing

Enumeration under USP <61> and tests for specified microorganisms under USP <62> — the pair that releases a non-sterile product.

USP <61>USP <62>USP <1111>

Sterility Testing

Membrane filtration or direct inoculation under USP <71>, with the bacteriostasis and fungistasis suitability work that has to come first.

USP <71>

Growth Promotion Testing

Lot-by-lot qualification of your culture media — proof that every batch of plates and broth recovers the compendial challenge organisms before you trust a result to it.

USP <61>USP <62>USP <71>

Ready to scope your bioburden testing?

Send us the product and the claim you need to support. We'll confirm the method, the sample count and the turnaround before anything ships.

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