Meat and milk may not be cooked together. If they were, it is forbidden to eat or benefit from the resulting food. This prohibition is different from the other kosher laws. First, all the other non-kosher foods are prohibited at all times, while meat and milk are acceptable separately and become prohibited only when cooked together. Second, this prohibition is more severe. Not only is eating the meat-and-milk combination prohibited, but so is deriving any type of benefit from it. It may not even be sold or given to a non-Jew.
A kosher kitchen must be equipped with separate meat and milk cookware, and it should be easy to distinguish between them to avoid mistakes. Similarly, a kitchen must have separate dishes and cutlery for meat and milk, so that people do not accidentally eat milk with meat leftovers or vice versa.
If meat is cooked in a dairy pot or vice versa, the food is prohibited. However, if this was done accidentally, it depends on the taste. If one can taste the meat in the dairy food (or vice versa), the food is prohibited; if the taste cannot be detected, it is permitted.
