What a CoA is and why it matters
A Certificate of Analysis is a document issued by an independent accredited laboratory that reports the results of testing a specific production batch. Unlike certifications (which audit processes), a CoA reports what was actually found in the product you are buying.
A current CoA from an accredited lab is the single most meaningful quality document for spirulina. Reputable producers issue them routinely and make them available on request or on their website. If a brand cannot produce a CoA, that is a strong reason to choose a different brand.
Section 1: Product identification
At the top of a CoA you will see:
- Product name and lot/batch number: The batch number allows you to match the CoA to the actual product you received. Match these — a CoA from a different batch has limited relevance.
- Manufacturing date and expiry: Confirms the CoA is current. CoAs older than 12 months are of limited value for safety assurance.
- Issuing laboratory:Should be an independent third-party laboratory, not the producer’s own internal lab. Accreditation (ISO/IEC 17025) is the standard to look for.
Section 2: Heavy metals — the critical safety section
Heavy metal contamination comes from the water used in cultivation. Acceptable limits to verify:
- Lead (Pb):<1 mg/kg (1 ppm). Some premium producers achieve <0.1 ppm. Above 1 ppm is unacceptable.
- Arsenic (As):<1 mg/kg total arsenic. Inorganic arsenic <0.1 ppm is the stricter standard some producers meet. Note: arsenic in spirulina is predominantly organic arsenosugars, which are much less toxic than inorganic arsenic — but total arsenic reporting is the norm.
- Mercury (Hg):<0.1 mg/kg. Lower is better; this should not be a difficult target to meet.
- Cadmium (Cd):<0.5 mg/kg. EC regulation sets 0.5 ppm as the maximum for food supplements.
These are the four metals that matter. Any CoA reporting only one or two of them is incomplete. A complete CoA reports all four.
Section 3: Microcystins (cyanotoxins)
Microcystins are hepatotoxins produced by contaminating cyanobacteria that can grow in open-pond spirulina systems. This section is present in quality CoAs but absent from many lower-tier producers.
- Acceptable limit:<1 µg/g (1 ppm) — the guidance threshold used by Health Canada and referenced by the European Food Safety Authority
- Testing method: ELISA (enzyme-linked immunosorbent assay) is common and adequate as a screening test. HPLC-MS/MS is more specific and confirms ELISA results. Both are acceptable.
- Result format:“Not detected” or a specific number below 1 µg/g. “Not detected” with a stated detection limit (e.g., ND <0.1 µg/g) is the best result.
If the CoA does not include microcystin testing, ask for it specifically. Producers who test for it are generally those who have invested in genuine quality infrastructure.
Section 4: Microbiological testing
- Total aerobic plate count (TPC):<100,000 CFU/g is typical; <10,000 CFU/g is good.
- Coliforms:<100 MPN/g; should be absent at <10 MPN/g in quality product
- Salmonella: Absent/negative in 25 g
- E. coli: Absent/negative
- Mould and yeast:<1,000 CFU/g
Microbiological contamination comes from poor harvesting or drying hygiene. An abnormal result here indicates a process failure.
Section 5: Nutritional composition
- Protein: Should be 55–70% by dry weight. Below 50% indicates poor growing conditions, contamination, or adulteration (addition of fillers).
- Moisture:Should be <7%. Higher moisture reduces shelf life and indicates incomplete drying.
- Phycocyanin: Not always listed on standard CoAs, but increasingly included by quality producers. 10–20% is the typical range; below 5% suggests excessive heat during processing.
How to request a CoA
If a CoA is not publicly available on the brand’s website:
- Email customer service: “Please send the Certificate of Analysis for lot number [X] from my recent order.”
- A quality producer responds within 48 hours with the document.
- A producer who responds with a generic marketing document, offers only internal testing results, or does not respond is a quality risk.
The response speed and completeness tells you as much about a producer’s quality culture as the document itself.
Red flags in a CoA
- CoA issued by the producer’s own laboratory (not independent)
- Missing any of the four heavy metals
- No microcystin testing
- CoA more than 12 months old
- Batch number on the CoA does not match the product packaging
- Protein content below 50% (possible adulteration or very poor growing conditions)