Musnad Ahmad 1060:30

Waki’ narrated to us, from Wasil al-Raqashi, from Abu Surah, from Abu Ayyub and from ‘Ata’, they both said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "How excellent are those who use the toothpick (al-mutakhallilun)." It was said: "And what are the mutakhallilun?" He said: "In wudu (ablution) and in food."