Manava Dharmashastra 11.153

11.153

śuktāni ca kaṣāyāṃś ca pītvā medhyāny api dvijaḥ
tāvad bhavaty aprayato yāvat tan na vrajaty adhaḥ //

But he who has eaten the food of men, whose food must not be eaten, or the leavings of women and Sudras, or forbidden flesh, shall drink barley (-gruel) during seven (days and) nights.