It is not permissible for a Muslim to eat meat that is not slaughtered in accordance with Islamic law, which has set certain conditions for the manner in which the animal should be slaughtered; these include that the slaughterer has to be either a Muslim or one of the people of the Scriptures (Jews and Christians). If the slaughterer is not from among the Jews and Christians, then the meat is haram.
Furthermore, meat slaughtered by one of the people of the Book (a Jew or a Christian) is permissible under two conditions:
1 –The meat should be slaughtered as a Muslim does it, by cutting the throat and esophagus and letting the blood flow. If the animal is killed by strangling or electric shock or drowning in water, its meat is not permissible. Similarly, if a Muslim does that, the meat is not permissible.
2 – No name other than that of Allah should be mentioned over it, such as the name of the Messiah etc, because Allah says: (Eat not (O believers) of that (meat) on which Allah’s Name has not been pronounced (at the time of slaughtering the animal)) [al-An’am 6:121]
If a Muslim or a kitabi (Jew or Christian) slaughters an animal for meat, and it is not known whether he mentioned the name of Allah over it or not, it is permissible to eat from it, and the one who eats it should say the name of Allah, because of the report that was narrated by al-Bukhari from ‘A’ishah that some people said: O Messenger of Allah, some people bring meat to us, and we do not know whether they mentioned the name of Allah over it or not. The Messenger of Allah (peace and blessings be upon him) said: “Mention the name of Allah over it and eat.” (Al-Bukhari)
The fact that there is no halal meat is not an excuse, because one can eat fish and seafood, or eat things other than meat, such as canned goods and vegetables. One can also look for an Islamic centre that provides halal meat for Muslims.
So the Muslim must strive to avoid what is obviously haram, and be cautious of doubtful things, and be keen to keep his religious commitment safe and to protect his body from haram foods.