In SIngapore, Spirulina is classified as a food additive. To qualify such products for sale and consumption, we require heavy metal and microbiological testing. Microbiological testing requires proper lab equipment and chemicals which are harder to acquire. Hence, we started with heavy metal testing. Heavy metal testing can be done with simple test kits made for drinking water. Water quality test kits usually come in the form of inkblot tests which requires a small sample of the solution.

I purchased a simple test kit and obtained the results below. The sample from my Spirulina culture indicated a high level of lead. This was a strange result as neither lead nor lead compounds were added at any point in the process. However, with the harvested sample that I processed to powder, no lead was observed.

Further investigation is required to determine the root cause of lead being present. However, it does look like the harvested Spirulina is suitable for consumption.

Tap Water / Spirulina Culture	Harvested Spirulina Powder dissolved in water	Reference

SFA Spirulina classification