Beans

Beans are a type of agricultural food consumed by humans. They are produced by plants which are native to Earth. Beans are available in certain Ration packs which are given to UNSC Marines, ODSTs and other UNSC personnel to sustain them during military operations. In certain missions throughout Halo 2 you can find different ration canisters, and it is possible to read the labels on them. There are many different types of beans, so it is unknown what kind the ones in the canister are. They are also mentioned in Halo: The Flood as "rations included beans..."