you really don't know whats in there

fish and dogs can thrive on a bacteria load that could kill a human. the bacteria population could be WAY imbalanced toward the unhealthy for humans side of the scales. now, it true your body could detox those bacteria, but why provide more of a toxic load on your body than is necessary?

the point is that you just don't know what you are dealing with.

of course you could grow your own spirulina, have you thought of that? i looked into it at one point, but it looks kind of like a pain in the #@!@. but really the most important thing is to find a starter culture. it would be an interesting experiment anyway.