I saw the Prophet ﷺ eating of a shoulder (of a sheep) by cutting from it and then he was called to prayer and he prayed without repeating his ablution. Narrated Az-Zuhri: as above (Hadith No. 173...) and added that the Prophet ﷺ put the knife down.  

رَأَيْتُ النَّبِيَّ ﷺ يَأْكُلُ مِنْ كَتِفٍ يَحْتَزُّ مِنْهَا ثُمَّ دُعِيَ إِلَى الصَّلاَةِ فَصَلَّى وَلَمْ يَتَوَضَّأْ حَدَّثَنَا أَبُو الْيَمَانِ أَخْبَرَنَا شُعَيْبٌ عَنِ الزُّهْرِيِّ وَزَادَ فَأَلْقَى السِّكِّينَ