Manava Dharmashastra 11.176

11.176

vipraduṣṭāṃ striyaṃ bhartā nirundhyād ekaveśmani
yat puṃsaḥ paradāreṣu tac caināṃ cārayed vratam //

A Brahmana who unintentionally approaches a woman of the Kandala or of (any other) very low caste, who eats (the food of such persons) and accepts (presents from them) becomes an outcast; but (if he does it) intentionally, he becomes their equal.