How to Read a Certificate of Analysis for Food Powders

A CoA is only useful if you know what to look for. Here's what each line means, which results matter most, and the warning signs that should stop a purchase.

Legacy Editorial · 31 Oct 2026 · 6 min read

How to Read a Certificate of Analysis for Food Powders

Photo: The U.S. Food and Drug Administration, Public domain, cropped

To read a food powder Certificate of Analysis, first match the product and batch number to your delivery, then compare actual results with the limits for moisture, microbiology and contaminants. A useful CoA shows numbers, units, methods and the laboratory, not just the word 'pass'.

A Certificate of Analysis (CoA) is a batch-specific document that records how a lot of material tested against its specification. For a food buyer, it is the fastest way to see whether a powder is what the seller claims. Many buyers file it without reading it, though. This guide explains how to read one properly.

First, check that it belongs to your lot

The product name matches your order.
The batch number matches the number printed on the bags.
The manufacturing and test dates make sense for the delivery you received.
The issuer is named, and external results identify the testing laboratory.
The document shows both the specification limit and the actual result, not just "pass".

Physical and chemical results

Moisture: excess water raises the risk of caking and spoilage. Compare it with the agreed limit for that powder.
Water activity: this measures how available the water is to microbes, so it can reveal more than moisture alone. Most microbes stop growing below about 0.6.
Particle size or mesh: this affects dispersion and mouthfeel. Finer powders are not always better, as they can dust and lump.
Total ash and acid-insoluble ash: high acid-insoluble ash can point to sand, soil or other mineral contamination, which matters for leaf and root powders.
Active markers: if you are paying for a marker, such as curcumin in turmeric, ask for the result and the test method.

Microbiological results

Dried does not mean sterile. Low moisture stops microbes from growing, but some can survive and become active again once the powder goes into a wet food. This is especially important if the powder is used in a product with no later cooking step, such as a drink mix or a dip.

Total plate count: a broad measure of general hygiene.
Yeast and mould: often relevant for powders that have been exposed to humidity.
Coliforms and E. coli: indicators of hygiene and possible faecal contamination.
Salmonella: pathogens are normally specified as absent in a defined sample, commonly 25 g, so check the sample size.

Contaminants

Contaminant tests are not always run on each batch. They are often done periodically, so ask how frequently they are carried out and when the last result was issued. Depending on the ingredient and market, look at heavy metals (lead, arsenic, cadmium and mercury), pesticide residues and aflatoxins. Export buyers should check limits against the destination market, because they are not the same everywhere.

Warning signs

Results that are identical across different batches, which may mean they were copied.
No test method or unit shown.
Vague results such as "complies" with no number behind them.
A "typical analysis" sheet presented as if it were a batch CoA.
Any sign of editing, or a laboratory that will not confirm the report.

Trust, but verify

A supplier's CoA is a starting point. For a new supplier or a critical ingredient, send a sample from a delivered lot to an independent, NABL-accredited laboratory and compare the results. Our product pages note where documentation is available on request, and we can share what you need to complete your supplier approval.

Frequently Asked Questions

What is a good water activity for food powders?

Most microorganisms can't grow below a water activity of about 0.6. The right limit for quality depends on the powder, so use the agreed specification.

Is a typical analysis the same as a Certificate of Analysis?

No. A typical analysis gives general values, while a CoA should report test results for your specific batch.