I would just make sure to keep cooking containers, serving containers, and utensils separate. As in, if you use the pan to cook the bacon, don't put the eggs in there after. If you use a spatula for the bacon, use a different one for the other items. I don't think it'll be a problem for her, as most people who are really strict would make it more obvious (and really, there is a strong precedent in the religion that when you eat with people who are your hosts, you eat without complaint.)