Cross-contamination is a risk you'll want to consider when you order a side of ketchup at any restaurant (unless it's a certified gluten-free location). When food is being prepared, flour can get into the air and settle on surfaces in the kitchen, your little cup of ketchup included, ...
All of the mayo labels said “organic” somewhere on the label. Two of them said USDA Certified Organic. But only one had “GMO free” in addition to “organic” on the label. Coincidentally, it was the only mayonnaise that wasnotmade from one the “Big Four” GMO crops (corn, soy, ...