First of all, it should be noted that Muslims are allowed to eat food prepared by any human being as long as the food is clean, healthy, and prepared with halal (lawful) ingredients. Moreover, Allah clarified in the Qur’an that the food of Ahl-Al-Kitab is halal for us, He says: (…The food of those who have received the Scripture is lawful for you…) [Al-Ma’idah 5:5]
Responding to this issue properly, Dr. Rajab Abu Maleeh, a Ph. D. holder and a Sharia consultant, stated that ‘If one is sure that the non-Muslims use the same cookware for preparing all the food – halal and haram food – then it is not permissible to eat their food. This is because, the remnants of food or the fat that leaks out of forbidden meat such as pork, will be mixed with other halal food, so it becomes haram.
However, if they are used to wash their cooking utensils and devices before preparing each order, or use separate cookware, then it is allowed to eat the food they prepare as long as they do not insert impure ingredients in the food.’