In this regard, a lot of research has been conducted but we did not find a trustworthy and reliable source to confirm the existence of animal ingredients like pork in Orbit chewing gum.
It should be noted that the sacred Shari'ah of Islam considers a thing to be impure only when one is certain that it is impure. But when we entertain doubt about whether or not something is impure, that thing is pure. Therefore, a thing is treated as clean, if we have doubt about its being impure.
We have also sought the verdicts of some of the grand jurists in respect of the same question. Here are the answers sent by their offices:
Office of grand Ayatollah Makarem Shirazi (may Allah grant him long life):
If you are certain that it has pork ingredients, it is not permissible to use it.
Office of grand Ayatollah Saafi Gulpaigani (may Allah grant him long life):
We have no information about its ingredients. Generally speaking, if it does not contain any thing which is viewed as impure according to Shari'ah, there is no problem, and if you have doubt about it, it is treated as pure.