A certificate of analysis, or COA, is the lab document that states what a specific lot of material actually contains and whether it meets its specification. It is the difference between a seller telling you a product is clean and a seller showing you. Knowing how to read one protects your formula, your label claims, and your customers.
What a COA is, and what it is not
A COA reports test results for one lot, identified by a lot or batch number and a date. It is not a marketing sheet and not a guarantee that every kilogram is identical. It is evidence that the tested sample from that lot met the stated limits on the day it was tested. Always match the COA in front of you to the lot you are actually buying.
The sections you will usually see
Formats vary by seller and by material, but most COAs for food and botanical ingredients cover the same families of tests:
| Section | What it tells you |
|---|---|
| Identity | Confirms the material is what it claims to be, often by appearance, odor, and sometimes botanical or chemical markers. |
| Physical | Particle size or mesh, moisture, ash, bulk density. These decide how the material behaves on your line. |
| Microbiological | Total plate count, yeast and mold, and pathogens such as E. coli, Salmonella, and coliforms, each with a stated limit. |
| Heavy metals | Lead, arsenic, cadmium, and mercury, reported against limits. Relevant for botanicals and root materials in particular. |
| Pesticides and residues | Screens against allowed limits, more common and more important on organic and botanical material. |
How to match a COA to your lot
Read the lot number and the manufacture or test date first. The COA is only meaningful for that lot. If you order again later, you should get a new COA for the new lot, not the old one. When a best by or retest date appears, note it against your own turnover.
Reading the numbers
Each result is shown against a specification limit. A result at or under the limit passes. Pay attention to two things: whether every listed test has an actual result rather than a blank, and whether the limits themselves match your requirement. A COA can pass its own spec and still be wrong for you if your spec is tighter.
Red flags worth a second look
- No lot number or date. A COA without a lot identity cannot be tied to your material.
- Missing test families. A botanical COA with no heavy metals or micro results is incomplete for most food uses.
- Results that only say "conforms." For safety parameters, ask for the actual measured values, not just a pass label.
- A COA that predates the lot. The test date should sit at or after the production date.
When you request a quote on bulk material, ask for the COA for the specific lot rather than a representative sample. A seller who can produce lot matched documentation on request is showing you how they operate. On Bulk Wholesale Ingredients, lot matched COAs travel with every quote; how verification works explains what the platform checks. For the wider sourcing process around the paperwork, see How to Buy Bulk Ingredients Wholesale.