CC Madhya 3.99
ihāke ‘jhuṭhā’ kahile, tumi kaile aparādha
Nityānanda Prabhu replied, “These are the remnants of food left by Lord Kṛṣṇa. If You take them to be ordinary remnants, You have committed an offense.”
In the Bṛhad-viṣṇu Purāṇa it is stated that one who considers mahā-prasādam to be equal to ordinary rice and dhal certainly commits a great offense. Ordinary edibles are touchable and untouchable, but there are no such dualistic considerations where prasādam is concerned. Prasādam is transcendental, and there are no transformations or contaminations, just as there are no contaminations or transformations in the body of Lord Viṣṇu Himself. Thus even if one is a brāhmaṇa he is certain to be attacked by leprosy and bereft of all family members if he makes such dualistic considerations. Such an offender goes to hell, never to return. This is the injunction of the Bṛhad-viṣṇu Purāṇa.