Can food keep cool underground

Yes. The temperature is always cooler underground. There have been several people who have made underground homes and gardens. We have one in this area and it gets a 100+ in the summer, but he was able to keep his home and garden cool with no air conditioning because it was underground. Before modern ways to keep food cold people had "root cellars" where they kept food because it would keep the food cooler. In some cases they would put blocks of ice in as well with sawdust to keep it from melting so fast and they could actually keep ice cream there.