What is the ruling on eating meat in non-Muslim countries if the Tasmiyah (invocation of Allah's name) was not pronounced at the time of slaughter, and is it sufficient to pronounce the Tasmiyah when eating, or is the Muslim considered to be in a state of necessity in this case?

The mention of Allah's name (Tasmiyah) is a condition for an animal to be lawful (halal) to eat, and it is not waived due to forgetfulness or ignorance. The animal slaughtered by a person of the Book (Jew or Christian) is lawful under two conditions: that they slaughter it as a Muslim would, and that they do not mention any name other than Allah's over it. If it is unknown whether Allah's name was mentioned over the slaughtered animal or not, it is permissible to eat from it while mentioning Allah's name yourself. It is permissible to eat from the slaughtered animals of the People of the Book in non-Muslim countries, unless it is known that they slaughter in a manner other than the Islamic way or mention a name other than Allah's over it. However, the animal slaughtered by an idolater or a communist is not lawful. It is not permissible to eat from what is forbidden except in a state of extreme necessity where one finds nothing else to preserve their life. Fish is lawful in all circumstances.