If I work at a place, and one if my managers gets food from McDonald's and heats up his sandwhiches on our grill. Will the grill become impure given that it is well known that McDonald's cooks their breakfast sandwiches as well as other beef sandwiches along with bacon on the same grill? I have two cousins who worked at a McDonald's and told me this. Will that make the food impermissible because of the strong chance of cross contamination, or is our grill at work pure?

All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.

That grill does not become impure and it is not forbidden to eat what was heated on it just because of heating up McDonald's sandwiches on that grill, because firstly, it is not sure that these sandwiches are impure, and secondly, it is not certain that the probable impurity is transmitted to or touched by what is heated on the grill. Food is not thrown away just because of suspicion.

Ad-Dardeer (from the Maaliki School of jurisprudence) said, “Or it was the food leftover by an alcohol drinker ... then it is not disliked to eat it, as food is not thrown away because of suspicion.”

Allah knows best.