My sister ate expired relish...?

My sister took relish from our second fridge and put it on her hot dog. I came into the room a few minutes later, and my sister had eaten more the half of the hot dog. I was about to use it, but I checked the best before date first. It said April 3, 2011 (I don't know what's wrong with my family, we don't really use the second fridge much). What will happen to my sister? What should I do for her?