Narrated Abu Said Al-Khudri: We used to give one Sa' of meal or one Sa' of barley or one Sa' of dates, or one Sa' of cottage cheese or one Sa' of Raisins (dried grapes) as Zakat-ul-Fitr.
— Sahih Bukhari, Volume 2, Book 25: Obligatory Charity Tax After Ramadaan (Zakat ul Fitr), Hadith #582
