If a Brahmana, who has set up the sacred fire and who performs sacrifices, were to die with any portion of a Shudra's food remaining undigested in his stomach, he is sure to be born a Shudra.
शूद्रान्नेनावशेषेण जठरे या म्रियेद् द्विजः। आहिताग्निस्तथा यज्वा स शूद्रगतिभाग् भवेत्॥