Spice Quality Specifications Explained: ASTA, Curcumin, Moisture & Mesh

When two suppliers quote the same spice at different prices, the difference is almost always in the specification. Knowing how to read these parameters lets you compare offers fairly, write a contract that protects you, and verify each delivery against what you agreed. The figures below are indicative industry ranges — confirm exact tolerances per contract.

ASTA colour value

ASTA colour (named after the American Spice Trade Association method) measures the extractable colour pigment in red spices like chilli and paprika. A higher ASTA number means a deeper, more intense red. Buyers in food manufacturing often specify a minimum ASTA because colour drives the visual appeal of the finished product.

Where to see it

Compare the red chilli powder and high-colour Kashmiri chilli powder pages, which list ASTA against grade.

Curcumin content in turmeric

Curcumin is the active polyphenol that gives turmeric its colour and much of its functional value. It is expressed as a percentage; Indian turmeric typically falls around 2–5%, with premium export grades at the higher end. Nutraceutical and extract buyers usually specify a minimum curcumin percentage.

See indicative curcumin grades on the turmeric powder page.

Moisture content

Moisture is a safety and shelf-life parameter. Too much moisture invites mould and aflatoxin and shortens shelf life; most ground spices are specified at roughly 10% maximum (it varies by spice). Moisture is measured per batch and stated on the CoA.

Mesh size (grind fineness)

Mesh size describes how finely a spice is ground — the number refers to the sieve the powder passes through, so a higher mesh number means a finer powder. Common ground-spice specs are 60, 80, or 100 mesh. Match the mesh to your application: finer for blends and ready-meals, coarser for visible flecks or grinders.

Microbial and aflatoxin limits

These are the safety specs that decide border clearance. Microbial parameters (total plate count, yeast & mould, and pathogens such as Salmonella) and mycotoxins (aflatoxins, and ochratoxin A for some spices) are tightly regulated in destination markets.

• EU — for the relevant spices, aflatoxin B1 and total aflatoxins are capped at low single-digit and low double-digit µg/kg levels respectively, with ochratoxin A limits for certain spices. Salmonella must be absent.
• US (FDA) — the action level for total aflatoxins in food is 20 µg/kg (20 ppb).

How to read a Certificate of Analysis (CoA)

The CoA is the per-batch lab report that ties every spec above to the specific lot you're buying. When you receive one:

1. Check the lot/batch number matches the consignment and the packing list.
2. Confirm each parameter (moisture, ASTA/curcumin, mesh, microbial, aflatoxin) is within the contracted tolerance — not just present.
3. Verify the test methods and lab are credible (ideally accredited).
4. Keep the CoA on file for your own due-diligence and traceability records.

Every shipment we send carries a per-batch CoA. See our full quality and testing process or request a quote with your target spec.