Is the company like KFC, al-Baik, MacDonald, foods are halal or haram? They saw halal certificate. Their certificate are valid or not valid they answered that link below:
بسم الله الرحمن الرحيم
(Fatwa: 1017/1129/L=9/1438)
You should avoid eating the meat about which you are not sure whether it was slaughtered according to Shariah or not. As those who issue halal certificate usually do not fulfill all the conditions hence merely by writing halal on the packet of meat it shall not be termed halal.
Allah knows Best!
Darul Ifta,
Darul Uloom Deoband