I found a lot of a white powdery substance under my carpet. could that be mold or is it carpet fresher?

Our washing machine over-flowed and got the carpet wet in 2 bedrooms and half way down the hall. When I pulled the carpet padding up I found a lot of a white powdery substance. I think it is just carpet freshener. We use that once a week before we vacuum. I put the wet padding in a pile and where the water dripped out, there was a large amount of white powder on the concrete. It looked like it had grown into one half inch pile. I am just concerned that the way it looked like it had grown or crystalized, it might be mold.