It is narrated from Sayyiduna Aws bin al-Hadathan (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "Give the charity of breaking the fast (sadaqat al-fitr) as one sa' of food." And our food at that time was wheat, dates and raisins.
These are the words of Zayd bin Akhzam, while Sha'tham said: "And our food at that time was dates, raisins and dried curd (aqit)."
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 609