Microbiological testing

What a microbiology panel covers

How the testing works

The laboratory takes a defined amount of the sample, prepares a dilution, and grows any microbes on culture media designed for each group, under set temperatures and times. Colonies are counted and converted into colony-forming units per gram. For pathogens, a larger portion is often enriched to detect even small numbers, and the result is given as detected or not detected in that portion.

Understanding the results

“cfu/g” means colony-forming units per gram, an estimate of viable microbes. A result shown as “< 10 cfu/g” means below the method’s reporting limit. “Absent in 25 g” means the organism wasn’t found in a 25 g test portion. Larger tested portions make “absent” more meaningful; see detection limits.

Reference values

Laboratories compare microbiology results with reference values, which may come from pharmacopoeia guidance, industry standards or the brand’s own specification. Because these vary, ask which reference values were used. A report that lists results without any reference makes it harder to judge whether counts are acceptable.

Where microbes come from

Shilajit is collected from rock faces, stored, purified and dried. Damp storage, slow or open-air drying and handling can all raise microbial counts, and products sold as raw or sun-dried deserve particular attention; see microbial contamination, drying and “raw” and “sun-dried” claims.

A microbiology panel in practice

The AGROLAB LUFA report for Nature Elixirs batch SJ2509 includes microbiology alongside metals, mycotoxins, pesticides and PAHs, from a laboratory stating ISO/IEC 17025 accreditation.^[1] Nature Elixirs is a brand evaluated by Best Shilajit UK. Read our evaluation to see the evidence and documentation we reviewed.

Microbiology and mycotoxins

Moulds can produce mycotoxins such as aflatoxins, which remain even after the mould itself is gone. A low mould count is reassuring, but mycotoxin testing answers a separate question; see other contaminants.

After purchase

A good result describes the product when tested. At home, a wet scoop or open jar can introduce microbes. Keep the jar sealed and use a dry scoop; see storage.

What to ask a brand

1. Which organisms were tested?TVC, yeasts and moulds, and pathogens.
2. What sample sizes were used for pathogens?
3. Which reference values apply?
4. Was the finished batch tested?After drying and packing.

Why microbiology uses culture methods

Unlike metals, microbes are living organisms whose numbers change. Culture methods count those that can grow under defined conditions, which is what matters for spoilage and safety. Some laboratories also use rapid molecular methods to detect pathogens. Whatever the method, it should be named and validated for the sample type.

Microbiology by format

Putting it into practice

When you read a report, check that microbiology is present, that pathogens are reported as absent in a stated portion, and that counts are given in cfu/g with a reference. Then keep the jar dry and sealed at home.

Water activity and microbial growth

Microbes need available water to grow. Laboratories sometimes measure water activity, a measure of the water available to microbes rather than total moisture. Well-dried resin has low water activity, which limits growth; damp storage raises it. That is why drying during processing and dry storage at home both matter. If a report includes moisture or water activity, it adds useful context to the microbiology results, particularly for products sold as raw or sun-dried. Ask the brand whether moisture or water activity is monitored between batches. A brand that tracks these is managing microbial risk at its source, rather than relying only on the final test result, and that is a good sign of careful processing. Moisture control is one of the simplest and most effective safeguards in shilajit production, and one of the easiest for a brand to explain.

The bottom line

Microbiology testing checks overall microbial load and specific pathogens on the finished batch. Read results in cfu/g or “absent in” a stated portion, ask which reference values apply, and give extra scrutiny to raw and sun-dried products.

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