Rabia bin Shayban reported,
Someone asked Hasan bin Ali 
, "What do you remember of the Messenger of Allah ﷺ?"He replied, "He took me into the room where the charity was kept, and I picked up a date from it and put it in my mouth. The Messenger of Allah ﷺ said, 'Spit it out, for it is not lawful for the Messenger of Allah ﷺ nor for anyone of his household ﷺ.'"
Ahmad 1724
Sahihحدثنا محمد بن بكر حدثنا ثابت بن عمارة حدثنا
ربيعة بن شيبان أنه قال
للحسن بن علي رضي الله عنه ما تذكر من رسول الله ﷺ قال أدخلني غرفة الصدقة فأخذت منها تمرة فألقيتها في في فقال رسول الله ﷺ ألقها فإنها لا تحل لرسول الله ﷺ ولا لأحد من أهل بيته ﷺ
Its isnad is sahih. Muhammad bin Bakr Barsani, with a damma on the ba and a sakin on the ra, is trustworthy, one of the teachers of Ahmad. Bukhari gave him a biography in al-Kabir 1/1/48-49 without mentioning any criticism of him. Thabit bin Umara Hanafi is trustworthy, and has a biography in al-Kabir by Bukhari 1/2/166.This hadith is an abridgment of the one before it. It appears in Majma al-Zawaid 3:90, with some variation in its wording, where he said, Ahmad narrated it, and its narrators are trustworthy.See 1731.