Can Jews eat something that had pork in it but then you took the pork out before you ate it?!
Answers:
It depends on how strictly they adhere to the laws of Kosher (Kashrut). For the strictest, even one food--or even a cooking utensil-- touching another non-Kosher one would be enough to make it "unclean". But for many Jews (mostly Conservative or Reformed), there is a ranking system known as "passing", in which certain types of non-Kosher foods may be acceptable, or certain situations okay to eat non-Kosher foods.
For instance, my good friend in college had a mom who would eat ham when dining out, but not at home. Some Jews will eat ham but not pork, or shellfish but not pork or ham and so on.
This site gives reasons for Kashrut laws and admits that many times, there IS no reliable explanation as to why one meat is Kosher while another is not (for instance, fish wish scales are okay, but ones without are not).
http://www.jewfaq.org/kashrut.htm
In answer to your question, you'd probably get a different answer from each Jewish person you asked! Same thing for vegetarians and vegans.
No they can't. There are strict guidelines not only of what they can or can not eat, but also in the way they are prepared.
The same would apply to Muslims and Buddhists etc
no