Commentary for Genesis 39:6

AND HE KNEW NOT AUGHT HE HAD — he paid no attention to anything.

SAVE THE BREAD WHICH HE DID EAT. In the words of our Rabbis, this is a refined expression which refers to his wife.²¹⁹Bereshith Rabbah 86:7.
Rabbi Abraham ibn Ezra said in interpretation of the verse that whatever Potiphar possessed was left in the hands of Joseph excepting the bread which he ate. This he did not even permit him to touch since he was a Hebrew. It was the customary behavior of the Egyptians towards the Hebrews that they not permit the Hebrews to touch their food, because that is abhorrent to the Egyptians.²²⁰Further, 43:32.
Possibly this is so. Perhaps the interpretation of the verse is that his lord did not know of Joseph taking anything from him save only the bread which Joseph ate, but no other pleasures as young people are wont to do. Nor did he gather wealth and property, just as it is said of David, And I have found no fault in him since he fell unto me unto this day.²²¹I Samuel 29:3. Now the verse, Having me, he knoweth not what is in the house,²²²Verse 8 here. Joseph speaking to Potiphar’s wife. expresses another matter, namely, that he [Joseph’s lord] did not trouble himself to know about anything inside the house. But the present verse, Having him, he knew not aught, is an expression of negation; he knew that nothing in the house is [taken by Joseph except the bread which he eats].²²³See my Hebrew commentary, pp. 219-220.

ולא ידע אתו מאומה, in the house