Will applying this fertilizer impact the long term health of my soil?

I found this fertilizer in the garage from the previous owner- I don’t like to let things go to waste and it appears to be harmless enough.

However, I have heard that applying fertilizers can kill or hurt the microorganisms in the soil. I applied this on a test patch in my garden and got fantastic results, but I don’t want to apply everywhere without knowing long term effects. I think since it is organic and not from synthetic sources, it should be fine?

Open to education