If you’re going to the trouble to store food, you want to preserve its freshness and quality as long as possible. Containers play a big role in extending the shelf life of low-moisture, long-term food storage and even in eliminating insects. Here are some things to keep in mind.
Shelf life is extended when food is kept away from humidity, air, light and temperatures that are high, all of which destroy vitamins and food quality. Think of the acronym HALT (humidity, air, light, temperature) to help you remember. Food packaging affects the first three of these.
No. 10 cans, Mylar pouches and No. 2.5 cans
Low-moisture food, packaged in these containers using oxygen absorbers or vacuum sealing, is well protected from humidity, air and light. In humid climates, Mylar bags are an advantage because they do not rust. They can be stored in plastic tubs or other containers for further protection from punctures and from rodents, which have been known to eat through Mylar.
These containers are light-weight to transport, and you can open them and use food without exposing a large amount of it at a time. No. 10 cans are easy to stack in cardboard boxes, and Mylar bags can be stacked when stored in tubs or other containers.
Size No. 2.5 cans are about the size of a can of cocoa mix. Single people and couples may find these smaller cans helpful. If you want to try a product before you invest in a lot of it, this size is ideal. Cans this size can be good for foods you use only a tablespoon or two of at a time, like dried green peppers, celery, powdered eggs and butter powder, exposing a smaller amount of food by the time you finish the can. Food purchased this way is a more expensive, but it may be worth it. A group order with interested friends and neighbors can help to defray shipping costs.
High density plastic buckets offer better protection from light than buckets made with thin plastic. However, plastic buckets in general are air permeable, allowing oxygen to seep through the plastic into the food at a slow rate over time. Plastic buckets are not a big concern for storing wheat or beans long term. However, they are not recommended for long-term storage of foods like rolled oats or rice, which in the presence of oxygen go rancid over time, rendering them dangerous to eat.
This problem can be overcome for foods that deteriorate in the presence of oxygen by using plastic buckets lined with Mylar bags. The bags seal well, and the buckets offer protection from punctures and rodents. You can purchase food packaged this way (called Super Pails) from businesses that sell food storage, or you can purchase the bags at a nominal price online if you want to package food yourself.
Mylar bags can be purchased with zip seal tops, making them easy to seal using oxygen absorbers and to reclose after opening, protecting food from moisture. Some people prefer to ensure bags are sealed by heat sealing them instead of using zip seal closures.
The large quantities of food in buckets appeal to some people. They can be stacked to maximize storage space; however, it is not recommended that they be stacked more than three high as the lids can crack. Keep in mind that buckets can get heavier over time. How does that happen? Well, as we get older, they sure feel heavier to heft!
Occasionally, people are more hesitant to open large more expensive buckets to experiment with the food and use it, in comparison to opening smaller containers. If that’s you, consider buying food packaged in smaller amounts. It’s wise to open and use what you store so food does get too old, and so you know how you’ll use it before an emergency.
Low moisture food packaged with vacuum sealers is protected from humidity and air. However, packaging in transparent containers does not protect food from light. If you use this method with transparent containers, be sure to store food in a dark place away from light to preserve its nutrition and quality. The Utah State University Extension Service cautions that regular polyethylene bags are not suitable to maintain a vacuum.
Pests can be a problem, particularly when storing wheat and grains. Fortunately, food technology and processing have improved so much that we are seeing fewer problems with insects than we used to.
Studies show that insects in all stages are killed when they are kept in an environment of less than 1 percent oxygen for at least 12 days. Oxygen absorbers or vacuum sealing make this simple when containers are not air permeable, like metal cans, and Mylar pouches.
A recent study published by Brigham Young University tested whether the addition of more oxygen packets to high density polyethylene plastic five-gallon buckets with gamma seal lids could maintain a low level of oxygen long enough to kill insects. Over 17 days, tests showed that some buckets maintained less than 1 percent oxygen inside, while others did not. The unexpected results indicated that seals in the lids were undependable. Tests were duplicated with less expensive gasketed lids, which had an even higher failure rate.
Unfortunately, the consumer cannot detect which buckets have sealed well and which have not. Lining buckets with Mylar bags that are sealed would provide the needed oxygen barrier to effectively eliminate bugs.
Insects in food can also be destroyed by freezing; however, insect eggs are not affected, making it necessary to freeze food several times as insects hatch. This can be a real nuisance.
The USU Extension Service cautions that dry ice is not the most effective way of controlling insects in stored grain. Diatomaceous earth is also not recommended. Various DE formulations have not been tested and DE poses an inhalation hazard. Use of bay leaves, chewing gum, 10-penny nails and salt are all old wives’ tales (see http://extension.usu.edu/foodstorage/htm/insect-treatments).
It is not necessary to store wheat in an oxygen-deprived environment unless insects are present. It should, however, be stored away from moisture in food-grade packaging. It is possible to purchase insect-free wheat packaged in heavy plastic bags. If you store wheat this way you should be confident your home cannot be invaded by rodents.
Selecting the best food packaging makes a big difference to how well your low-moisture food will last over time, and using an oxygen-deprived environment to eliminate insects is a very simple solution to ensuring your food remains pest-free.
A few tips:
Tip: Great news! After opening low-moisture food in long-term packaging, you have around a year to use the food without a significant decline in nutrition or quality, as long as it is kept away from light and moisture. This gives you a nice amount of time to use what you opened. The exception is dry milk, which may develop strong flavors in the presence of oxygen and should be used in a shorter amount of time.