Srimad-Bhagavatam: Canto 9 - Chapter 1 - Verse 22
Sanskrit:
परिवेक्ष्यमाणं भगवान् विलोक्याभक्ष्यमञ्जसा ।राजानमशपत् क्रुद्धो रक्षो ह्येवं भविष्यसि ॥ २२ ॥
ITRANS:
parivekṣyamāṇaṁ bhagavānvilokyābhakṣyam añjasārājānam aśapat kruddhorakṣo hy evaṁ bhaviṣyasi
Translation:
While examining the food given to him, Vasiṣṭha Muni, by his mystic power, could understand that it was unfit to eat, being the flesh of a human being. He was very angry at this and immediately cursed Saudāsa to become a man-eater.