Freeze-drying food (also known as lyophilization or cryodesiccation) is a dehydration process used to preserve a perishable foodstuffs, and of course makes it more convenient to carry. Sealed freeze-dried foods can be stored at room temperature without refrigeration, and are protected against spoilage for many years.
One of the good things about freeze-drying is that it causes less damage to the food than other dehydration methods which use higher temperatures. Also freeze-drying does not usually cause shrinkage or toughening of the food (think jerky) being dried. In addition, flavours, smells and nutritional content generally remain unchanged.
In the bad old days of bush-walking, there was often very little choice but to carry bulky heavy camp food. Dried fruit, chocolate, and rice were then considered relatively lightweight hiking foods.
The foods you choose for your camping or bushwalking trip will depend on the type of food storage you have available, how much you can carry and whether safe water is available to add to camp food.
Some Recommended Camp Food:
- Dry, UHT and products in cans. Bushwalkers usually rely on dried or freeze-dried camp food which are safe and have the advantage of low weight and bulk. Remember to pack your dried food so they won’t get wet if it rains.
- Canned food is safe to keep at room temperature but it tends to be too heavy to carry in any quantity when bushwalking.
- Hard cheeses can be taken without refrigeration, or in an insulated cooler, but avoid taking fresh, unmatured soft cheeses unless you have access to refrigeration
- Fresh fruit and vegetables can be taken, but in warm weather some will deteriorate quickly so you may need some extra dried or canned varieties for later use. Most foods in cans or jars cannot be stored out of refrigeration once opened. Make sure that you buy containers small enough so that all the food is used up in one meal.
Perishable foods such as raw and cooked meats, poultry, chilled ready to eat foods, dairy foods and cooked eggs are generally unsuitable for camping holidays unless you have access to a refrigerator. If you have a cooler that depends on ice or ice bricks for cooling, you should not keep such food for more than one day unless the cooler is able to hold the temperature of the food at or below 5 degrees Celsius.
- If you are relying on dried food, make sure that you have access to enough safe water to rehydrate any food that will not be thoroughly cooked before consumption. Remember, water, even in remote and pristine wilderness is not necessarily safe and can be contaminated by animal faeces and naturally occurring parasites like Giardia. Unless you are sure that the water is safe, you should boil all water for at least one minute (a little longer if you are at high altitudes), or disinfect it in some way before drinking it or using it in powdered drinks or other uncooked foods.
- Avoid creating leftovers: discard them unless you can store them at or below 5 degrees Celsius until they are eaten.
- If you are going bushwalking overnight, you can take a frozen pre-prepared meal (eg stew or casserole) or frozen raw meat for cooking, provided that you eat it on the first night. Package the raw meat well so that the juices do not contaminate the rest of your camp food and bury the package deep in your backpack for extra insulation. Cook or reheat well.