What company came? Plumber? Carpenter? Mold expert? If it wasn't someone knowledgeable about mold then I would call someone who was before destroying anything else.

You might even Google "types of mold" and look at some pictures to see if anything resembles what you are seeing. But, I would still get an expert opinion before making a decision. I'm inclined to believe that it's not as bad as it seems but better safe than sorry. I think the cost of an expert opinion will be cheaper than ripping out miles of sheetrock and replacing it.

Hello, the water damage remediation company came. Not servpro but one of their competitors. They were recommended by insurance co. wood floors were warping so had to be ripped up before mold started to grow. but again what I saw on sheetrock, does not look like pics online-pics online look like circular colonies-this looked like some type of dust.
The water ran down this wall and when we opened it up I only saw and felt with my hand where water had trickled-its not as if something was leaking there for years and caused a mold problem. Definitely will consult with an expert before further removal of sheetrock into kitchen, cabinets etc. Thanks for your reply.