בראשית יח:ח פירוש: רש״י, רשב״ם, רד״ק וטור הארוך

ויקח חמאה וגו AND HE TOOK חמאה, ETC. — but he did not bring bread, on account of Sarah becoming mentstruant; as the 'way of women' returned to her that day, and the dough became impure (Bava Metzia 87a).

ויקח חמאה וחלב, according to the plain meaning of the text there was no need to report that Avraham supplied the bread which he had volunteered to serve these men. It was only necessary to list the additional items he served, seeing no mention had been made of them thus far.

ויקח, he, personally.