Why does it mention animal food before human food?
Radak: The land produces animal food by itself. Man must work for his food - "b'Ze'as Apecha Tochal Lechem" (Bereishis 3:19).
Why does it say "Lehotzi Lechem Min ha'Aretz"?
Radak: Man's work on the land is to take out [produce] from the land, for himself and for the animals used to work the land, e.g. cattle and donkeys. The choice food, wheat, is for himself; barley and straw are for the animals. "Lechem" refers to all food; it is mentioned primarily about bread, which is man's constant food - "v'Lechem Levav Enosh Yis'ad" (verse 15).
Malbim: "Tadshei ha'Aretz Deshe Esev Mazri'a Zera l'Minehu Etz Pri Oseh Pri" (Bereishis 1:11) teaches three kinds. (a) "Deshe" - the land is clothed with grass, which is primarily for animals to eat - "Matzmi'ach Chatzir la'Behemah." (b) "Esev Mazri'a Zera" are herbs that man seeds. The most important of them are the five grains, from which we make bread. Due to their importance, we bless on them ha'Motzi and Birkas ha'Mazon. We get bread from it only after great toil - threshing, grinding, kneading and baking - "la'Avodas ha'Adam Lehotzi Lechem." Also refer to 104:15:1:2.
