Peter Enns points out that Jethro eats bread with Moses just before Yahweh speaks with Moses in the burning bush at Mt. Sinai (Ex. 2:20, ch. 3), and later, Jethro shows up to eat bread with Moses and the elders just before Yahweh speaks with Moses and Israel at Mt. Sinai (18:12). And whereas only a bush was on fire the first time, the second time the whole mountain is in flames (Ex. 19:18).
Seems to me that this is a preview of the New Covenant Meal. First comes the bread, then comes the fire-wine. First comes the Bread of Life, then comes the Fire of the Spirit.