Imam al-Shafi'i (may Allah have mercy on him) said: "Allah, the Blessed and Exalted, says: 'All food was lawful to the Children of Israel except what Israel (that is, Ya'qub (peace be upon him)) had made unlawful for himself.' [Surah Al Imran: 93] (the verse)."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / Q19702