What should a new Muslim do if offered meat not ritually slaughtered, and he knows that eating it might cause embarrassment to the Muslim hosts who supported him?

Cattle that are killed before being slaughtered are considered carrion and are not permissible to eat, as Allah Almighty says: ﴿He has only forbidden to you dead animals, blood, the flesh of swine, and that which has been dedicated to other than Allah. But whoever is forced [by necessity], neither desiring [it] nor transgressing [its limit] - then indeed, Allah is Forgiving and Merciful (115)﴾. It is obligatory for a Muslim to refrain from eating such meat and to explain to others the reason for refraining from it. As for eating the slaughtered animals of the People of the Book, it is permissible unless it is known that they were slaughtered in a manner other than that prescribed by Islamic law, such as by strangulation, electric shock, or a blow to the head. In such a case, it becomes forbidden, just as it is forbidden for a Muslim.