Śatapatha Brāhmaṇa ("of a hundred paths") 2.4.3.9

2.4.3.9

tasya paricakṣā | yasyai vai kasyai ca devatāyai havirgṛhyate sarvatraiva sviṣṭakṛdanvābhakto 'thaitaṃ sarvameva juhoti na sviṣṭakṛte 'vadyati sā paricakṣoto hutaḥ paryāvartate

An offence (is thereby committed) by him; since, for whatever deity sacrificial food may be taken out, the Svishtakrit (Agni, the maker of good offering) is invariably allowed a share in it after (the respective deity). But that (cake) he offers entire, and he does not cut off a portion for the Svishtakrit this is an offence, and consequently (that cake), when offered, turns upside down.