Question: Why do Jews bring salt, bread and wine to a new home?
The idea is to make a small party as means to get to know the new neighbors. The bread (and salt) is the main items in a meal - (source: "Code of Jewish Law" O.C. 177:1; 167:5). We also bring wine to a new home. Being that this party is usually done on Shabbat, we need the wine for Kiddush. Moreover, it was the way Malki Tzedek greeted Abraham - (source: Genesis 14:18; "Zohar" Leviticus 3b; "Ta'amei Minhagim" 456; "Torah Lishmo" by Ben Ish Chai, 484).
With blessings from Jerusalem,
Rabbi Shraga Simmons