The word apavitra anna refers to food that is unacceptable for a Vaisnava. In other words, a Vaisnava cannot accept any food offered by an avaisnava in the name of maha-prasada. This should be a principle for all Vaisnavas. When asked, "What is the behavior of a Vaisnava?" Sri Caitanya Mahaprabhu replied, "A Vaisnava must avoid the company of an avaisnava [asat]." The word asat refers to an avaisnava, that is, one who is not a Vaisnava. Asat-sanga-tyaga,-ei vaisnava-acara (Cc. Madhya 22.87). A Vaisnava must be very strict in this respect and should not at all cooperate with an avaisnava. If an avaisnava offers food in the name of maha-prasada, it should not be accepted. Such food cannot be prasada because an avaisnava cannot offer anything to the Lord. Sometimes preachers in the Krsna consciousness movement have to accept food in a home where the householder is an avaisnava; however, if this food is offered to the Deity, it can be taken. Ordinary food cooked by an avaisnava should not be accepted by a Vaisnava. Even if an avaisnava cooks food without fault, he cannot offer it to Lord Visnu, and it cannot be accepted as maha-prasada. According to Lord Krsna in the Bhagavad-gita (9.26):

"If one offers Me with love and devotion a leaf, a flower, a fruit or water, I will accept it."