Every other authenticity guide in this series is about something added, substituted or diluted. Spirulina's principal risk is a different organism growing alongside it in the pond — producing a hepatotoxin that is invisible, odourless, and undetectable by protein assay, colour value, microscopy or any other line on a normal certificate. Only one test finds it.
How Contamination Happens
Spirulina (Arthrospira platensis) is a cyanobacterium cultured in alkaline water. Most commercial production uses open ponds — economical, scalable, and open to the environment.
Open water invites other organisms. The one that matters is Microcystis, another cyanobacterium, which produces microcystins — a family of hepatotoxins.
Two points to be precise about:
- Spirulina does not produce microcystins. Clean spirulina from a clean pond contains none. This is a purity question, not a property of the species.
- Contamination is a cultivation event, not a processing one. No downstream purification of a nutritional biomass reliably removes it — the toxin is in the harvested material.
Why It Is Invisible
This is what makes microcystins different from every other risk in this ingredient series.
| Check | Detects microcystins? |
|---|---|
| Appearance, colour | No |
| Odour, taste | No |
| Protein assay | No |
| Phycocyanin / colour value | No |
| Microscopy identity | Only gross contamination, unreliably |
| Heavy metals, microbiology | No |
| LC-MS/MS | Yes |
Read that table carefully. A spirulina certificate can be complete, accurate and entirely reassuring on every line — and silent about the ingredient's principal hazard. This is why the microcystin line is not one parameter among many on a spirulina specification; it is the parameter, and everything else is secondary to it.
What Adequate Testing Looks Like
Three requirements, and each matters:
- LC-MS/MS. Microcystins are a family of related toxins, and adequate testing must cover the relevant congeners. Ask what the method covers, not just that testing was done.
- Every batch. Contamination is a pond event — it can affect one harvest and not the next. Annual or periodic testing does not control a batch-variable risk.
- A measured figure, not "complies". You cannot construct a compliance position, an intake calculation or a trend from the word "complies".
Cultivation Method Is a Risk Driver, Not a Substitute
| Method | Contamination exposure | Still needs testing? |
|---|---|---|
| Open pond | Higher | Yes |
| Closed photobioreactor | Lower | Yes |
A closed system is a genuine risk reduction and worth paying for where your market demands it. It is not a reason to drop the test. Require the method declared and the result measured.
Route 2 — Colour Value Inflation
Moving to the commercial issues. As covered in our standardisation guide, colour value depends on measurement conditions — solvent, pH, concentration, wavelength.
A supplier can report a strong colour value obtained under favourable conditions. Nothing is falsified; the number is real under those conditions. It is simply not comparable to another supplier's figure or predictive of performance in your system.
What catches it: requiring conditions stated on the certificate, and matching them for independent verification.
Route 3 — Dilution With Cheaper Green Material
Spirulina powder is a deep blue-green powder. Other algal powders and various plant powders are green and cheaper.
What catches it: protein assay by Kjeldahl — spirulina is exceptionally protein-dense at NLT 60%, and most green diluents are nowhere near it, so dilution shows up directly. Supported by microscopy, since spirulina's spiral filaments are morphologically distinctive, and by phycocyanin content.
Route 4 — Powder Quoted Against a Phycocyanin Specification
A specification failure rather than a fraud, and common because the two products share a name in conversation.
Whole biomass and purified phycocyanin differ several-fold in price and entirely in composition. What catches it: colour value, decisively — and colour, since biomass is blue-green while phycocyanin extract is bright blue.
Route 5 — Undeclared Irradiation
Worth including because spirulina's profile invites it.
Dried biomass harvested from open ponds carries a higher natural microbial load than a solvent-extracted botanical, and irradiation is sometimes used to bring counts into specification. Many buyers and markets do not accept irradiated material, and it must be declared.
What catches it: requiring an explicit non-irradiation declaration rather than assuming, and treating suspiciously low microbial counts on an open-pond product as worth a question.
The Testing Package
| Test | Catches | Method |
|---|---|---|
| Microcystins, every batch, as a figure | The principal safety risk — nothing else finds it | LC-MS/MS |
| Cultivation method declared | Risk-level disclosure | Documentation |
| Protein by Kjeldahl, dry basis | Dilution with green material | Kjeldahl |
| Microscopy identity | Non-spirulina material; gross contamination | Microscopy |
| Colour value with conditions | Colour inflation; product confusion | UV |
| Non-irradiation declaration | Undeclared irradiation | Documentation |
| Acid-insoluble ash NMT 1% | Sand, soil, grit from harvest/drying | IP-2014 |
| Heavy metals by ICP-MS | Culture-medium and water contamination | ICP-MS |
| Full microbiological panel | Open-pond microbial load | USP |
Practical Steps for a Buyer
- Make microcystins the first line of your specification, not a footnote in the contaminant table.
- Require LC-MS/MS, every batch, as a measured figure. Ask which congeners the method covers.
- Require cultivation method declared — and do not treat a closed system as a substitute for testing.
- Verify microcystins independently on first order. Of every ingredient in this range, this is the clearest case for third-party testing, because no other check substitutes for it.
- Require a non-irradiation declaration.
- Use protein to detect dilution and colour value to detect product confusion.
- Re-verify on any change of production site or pond. Contamination is site- and season-variable.
SV Botanica tests microcystins by LC-MS/MS on every spirulina batch and states the measured figure, declares the cultivation method, assays protein by Kjeldahl and confirms identity by microscopy and HPLC. Buyer-nominated third-party pre-shipment testing is welcome and encouraged — see the supplier evaluation guide, or the product specification.
Source Microcystin-Tested Spirulina from India
Microcystins by LC-MS/MS every batch · cultivation method declared · phycocyanin colour value stated · protein NLT 60% · CoA-backed · samples for qualified buyers