Muslims can’t eat meat that has been slaughtered in a way that is not halal. This means that the animal must be killed by hand, with a sharp knife and no other instrument. The person doing the slaughtering must say ‘Bismillah’ (In the name of God) before he does so, and then God’s name should be mentioned again after each time he cuts off a piece of flesh (the head, neck and jugular vein). If any other animal dies accidentally or is found dead, it cannot be eaten unless its blood has been completely drained out.
Muslims cannot eat meat that has been processed in a way that is not permitted under Islamic law – for example if it contains alcohol or vinegar as additives to preserve it. Foods made using pork fat are also impermissible because this is considered to be an adulteration of permissible products by something which renders them forbidden (haram).
Similarly, halal foods may not be contaminated with impurities such as blood from non-permitted animals such as dogs or cats; nor may they come into contact with any other substance which would render them unfit for consumption under Islamic law e.g., wine etc..