The banquet is served on three separate tables. Joseph at one. His brothers at another. The Egyptian officials at a third. The Torah notes the separation briefly. Targum Pseudo-Jonathan explains it without blinking.
"It was not proper for the Mizraee to eat bread with the Yehudaee, because the animals which the Mizraee worshipped the Yehudaee ate" (Genesis 43:32). Egypt worshipped the ram and the bull. The Hebrews slaughtered them for dinner. A shared table was unthinkable.
The Targum is not prudish about this. It names the theological collision plainly. Two civilizations cannot sit at the same meal when the main course of one is the god of the other. Culinary law, in Judaism, is inseparable from theology. What you eat declares what you do not worship.
This detail also sharpens the poignancy of the scene. Joseph, who will soon reveal himself to his brothers, eats at his own Egyptian-style table — alone. He cannot sit with his brothers without giving himself away as a Hebrew. He cannot sit with the Egyptians without turning his back on his father's house. So he sits by himself, a ruler in a room of three unbridgeable tables, wearing a mask in front of everyone.
The sages hear in this verse a warning that echoes throughout exile: you can rise to the top of a foreign court, but the seating chart will always remind you where you actually belong. Joseph's solitary table is, in the Targum's telling, the first glimpse of the long Jewish pattern — present at the meal, separated by law, trusted with the kingdom, never quite at home.