Dried fruit. Biscuits. Hard bread. A little bit of jerky and something like trail mix. All told, maybe a week's worth of food for one person. But she'll run out of water in a couple of days unless it rains.
The island is made of some strange coral-like rock, tiny thin-walled cells that are very delicate alone but surprisingly tough packed together, covered by a layer of dirt thinner and thicker in some places and then by a lot of Earthly and otherworldly plants. There's some tall grass with floaty seeds, bushes and shrubs, an alien plant with thick, waxy leaves like palm fronds, some trees. There are few insects - these tiny barnacle-jellyfish things seem to have out-competed them. There are a few squirrels, some birds, and a small colony of manta-ray-shaped floating critters resting on a sort of mangrove clinging to the side of the island.
In terms of forage there are some unfamiliar maybe-poisonous berry bushes, and wild onions, if she recognizes wild onions.