@trevor75,
It's almost certainly a mold, but I doubt it's a slime mold. Typically Slime Molds occur out doors on rotting wood or other material.
Unfortunately I have no idea how to identify a hummus mold. Mold spores are ubiquitous so almost every food item in your refrigerator probably has them, but they usually don't germinate (or whatever fungi do), especially in the refrigerator.