وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ ثَوْرِ بْنِ زَيْدٍ الدِّيلِيِّ، عَنْ عَبْدِ اللَّهِ بْنِ عَبَّاسٍ، أَنَّهُ كَانَ يَقُولُ مَا كَانَ فِي الْحَوْلَيْنِ وَإِنْ كَانَ مَصَّةً وَاحِدَةً فَهُوَ يُحَرِّمُ ‏.‏

Yahya related to me from Malik from Thawr ibn Zayd ad-Dili thatAbdullah ibn Abbas said, "The milk which a child under two years oldsucks, even if it is only one suck, makes the foster relatives haram." Translation Not Available

Book Ref: Muwatta Imam Malik Book 30 Hadith 1278
Web Ref:  Muwatta Imam Malik Book 30 Hadith 4