Sahih Al Bukhari Hadith Number 1510

Narrated Abu Sa`id Al-Khudri: In the lifetime of Allah’s Messenger (peace be upon him) , we used to give one Sa’ of food (edible things) as Sadaqat-ul-Fitr (to the poor). Our food used to be either of barley, raisins (dried grapes), cottage cheese or dates.

24  Obligatory Charity Tax (Zakat)
Hadith number 1510
Volume no 2
Chapter: 76 (Sadaqat-ul-Fitr is to be given before the ‘Eid prayers)