The Talmud Yerushalmi (Pesahim 6:4) establishes that if a person eats a dairy meal and then prepares to eat a meat meal, he must remove the pieces of bread that were on the table during the dairy meal (listen to audio recording for precise citation). Given the concern that the bread came in contact with dairy food, it may not be used with a meat meal.
Hacham Ovadia Yosef ruled that this Halacha applies only to the pieces of bread cut from the loaf, but not to the loaf itself. The actual loaf of bread generally remains separate from the other foods on the table, and we are therefore not concerned that it came in contact with dairy food. This concern arises only regarding the pieces that were cut from the loaf to be eaten together with the other foods on the table. Hence, a loaf that was on the table during a dairy meal may be brought to the table for a meat meal. This is, of course, on the condition that one was careful not to cut the loaf with a knife used with dairy foods.
What is the status of other Parve foods, such as salads, with respect to this Halacha? If a person served salads with a dairy meal, may he then bring those salads to the table for a meat meal?
Strictly speaking, one may use the salads for a meat meal, provided that he was careful to keep them away from dairy foods, meaning, that special, Parve serving utensils were used for the salads. So long as one made a point not to serve the salad with the same utensils used for the dairy foods, the salad may, on the level of strict Halacha, be served again at a meat meal.
Nevertheless, Rabbi Moshe Feinstein (Russia-New York, 1895-1986), in his work Iggerot Moshe (Y.D. 38), ruled that as a "Misva Min Ha'mubhar" (higher standard of Misva observance), it is preferable not to serve the salads at a meat meal. Particularly when young children are present at the table, one cannot always ascertain that no dairy food made it way into the salads on the table, and it is therefore advisable not to serve the salads at a meat meal. Thus, although serving the salads at a meat meal is technically permissible, it is preferable not to use them with meat.
Summary: One may serve at a meat meal a loaf of bread that was served during a meal, provided that care was taken to keep the loaf away from dairy food. One may not, however, serve the pieces of bread that were cut from the loaf during the dairy meal. Parve foods such as salads served at a dairy meal may, strictly speaking, be served at a meat meal, though preferably this should not be done.
