Cleaning chemicals or other toxic substances unlabeled or stored where they can reach food.
Scoops and other in-use utensils stored improperly (e.g. handle down in the food).
Dirty wiping cloths not stored in sanitizer, or soiled linens handled improperly.
Surfaces that touch food — cutting boards, ice bins, dish racks — soiled or not sanitized.
Plumbing not installed or maintained properly — leaks, mop sink issues, unserviced water filters, or missing backflow prevention.