Coincidence? I think not.

Probably comes from the beef itself (corrected by someone else, came from the onions) since it’s an outbreak on a wide scale.

McDonald’s workers where I live don’t wear gloves yet there’s no outbreak. Wearing gloves isn’t more sanitary (it increases the odds that people won’t clean their hands often enough), you still touch the gloves to put them on, if your hands are dirty the gloves are contaminated, if someone touches the gloves box with dirty hands then the surface is contaminated and cross contamination can happen every time someone takes a pair of gloves.