Anushasana Parva 142.15

The food that comes from cruel and fierce persons is censurable. So also is the food that has been cooked for serving a large number of persons. The same is said of the food that is cooked for the first Shraddha of a dead person. So also is the food that is sullied for the usual faults and the food that is supplied by a Shudra. These should never be taken by a Brahmana at any time.