This is a good article about how the US classifies the different grades of algae. Knowing the difference between Organic, Natural, and aminal food quality Spirulina is very popular information to consumers. There is a big push for going organic. If you follow the paper trail from the US basically says the only approved organic process for cultivating Spirulina is by using a nitrification system to supply nutrients to the algae. They also emphasize how important it is to have a green commercial facility to obtain organic label status. It is nice to know having a responsible commercial process is just as important as having organic ingredients. The article was written in 2005.