Muslim followers cannot consume the following:
pork or pork by products
animals that were dead prior to slaughtering
animals not slaughtered properly or not slaughtered in the name of Allah
blood and blood by products
alcohol
carnivorous animals
birds of prey
land animals without external ears
The prescribed method of slaughtering all animals excluding fish and most sea-life per Islamic law. This method of slaughtering animals consists of using a well sharpened knife to make a swift, deep incision that cuts the front of the throat, the carotid artery, wind pipe and jugular veins but leaves the spinal cord intact.
The head of an animal that is slaughtered using halal methods is aligned with the Qiblah (Mecca). In addition to the direction, permitted animal should be slaughtered in the name of Allah (the Lord) and the person who is slaughtering should be a Muslim and he/she should be in a good mental condition and faith.
Let me know when you find a practising Muslims in ‘good mental condition,’ it’s definitionally impossible.
They also cannot cook their food in microwave ovens if pork has been cooked in there. A year or so ago there was a demand by Muslim employees that they have a separate microwave in the employee cafeteria for that reason.