Aśauca-vidhi (Rules of Impurity) within Śrāddha-kalpa — Chapter on Testing/Selecting Brahmanas and Honoring the Atithi
पुष्पमूलफलैर्वापि तुष्टा गच्छेयुरन्ततः / यावन्न श्रपितं चान्नं यावतौष्ण्यं न मुञ्चति
puṣpamūlaphalairvāpi tuṣṭā gaccheyurantataḥ / yāvanna śrapitaṃ cānnaṃ yāvatauṣṇyaṃ na muñcati
Even with flowers, roots, and fruits, the Pitṛs are at last satisfied and depart—so long as the cooked food has not yet lost its warmth.