How Dangerous Is Expired Salad Dressing? Share Photo: gvictoria, Shutterstock For some reason, people of a certain age love to collect bottles of expired salad dressing. In fact, a recently expired bottle of supermarket dressing in my own fridge is just one more damning piece of evidence I am slowly morphing into my grandmother, one food item at a time (the package of cheap bologna only confirms it). But what of those expiration dates? Do they really mean anything, or are they just part of scheme to get us to buy more salad dressing? To answer these burning questions, I contacted Dr. Donald Schaffner, extension specialist in food science and distinguished professor at Rutgers University.