However, it would be dangerous to leave cans in boiling water for a prolonged period of time. Extracted from web article by Melinda Hemmelgarn, M.S., R.D., Associate State Food and Nutrition Specialist, Florida Cooperative Extension Service. Food poisoning bacteria grow rapidly at warm temperatures. Even a day hiking in the wilderness with perishable foods stored improperly could result in illness. If you pack carefully it is possible to use fresh foods for meals the first day.
Many campers drive to their campsites with coolers, and have access to grills.
Foods can be prepared in advance, refrigerated or frozen, and packed with a cold source. Freeze water in a plastic jug and wrap it with the frozen foods in a plastic bag, then stuff the bag inside a sleeping bag in your backpack. This way the food will be kept cold while you hike. On the other hand, many backpackers choose foods that do not require refrigeration. Canned meat, poultry, and fish although heavy are good choices.