Is it permissible to eat meat provided in European refugee camps when one cannot be sure it is halal, and merely saying "Bismillah" is deemed sufficient?

The basic principle is that the food of the People of the Book is permissible, except for meat. However, it is not recommended to eat their meat, not because it is forbidden in itself, but because of their current slaughtering methods. They kill cattle with bullets and stun sheep and chickens with electricity. Thus, it is not known whether the animal died from these methods or from the actual slaughtering. With this doubt, the animal is not lawful to consume. One can do without their meat by consuming other foods. However, if abstaining from eating meat were to cause harm, then it is permissible to eat it out of necessity.