This is a perfect picture of cross-contamination. I left a little bit of food on top of the jelly when I was scooping it onto my peanut butter. It blossomed. Someone else would throw it all out but I scooped it out and the surrounding jelly, and refrigerated it. It was not refrigerated prior, thus a perfect habitat for mold. Bon Apetit!
The moral of the story is: use clean utensils and refrigerate open bottles of food.