Commercially canned foods are packed in metal cans that are actually made of steel, with a tin coating on the outside as well as the inside. Intense heat is then applied to sterilize the food, killing most of the bacteria and enzymes that cause food spoilage. The heat also thoroughly cooks the food inside the can.
Contrary to popular belief, very few preservatives are used in canned foods. Sodium is added for flavor, not to extend the food’s shelf life.can of ranch style beans
The Federal Emergency Management Agency (FEMA) recommends store-bought canned foods for emergency preparedness because they store well and they do not require cooking, water, or special preparation.
Canned chili, for example, is packed with protein and carbohydrates and requires a minimum amount of time and fuel to prepare. It is a great emergency food, as are canned soups.
In a pinch, canned foods can even be heated with a candle or eaten cold.
The University of Illinois did an extensive study of 84 fresh, frozen, and canned foods. The study showed that the canned goods were equal to and occasionally better in nutrient levels that the other foods.
This is possible because canned foods go straight from the field to the canning processor, whereas fresh foods spend days traveling across the country and sitting for even more days in the produce section at the supermarket.
This extra time and exposure allows the vitamins and nutrients to degrade.
Canned food is also one of the least expensive parts of an emergency preparedness plan. Keep an inventory of the canned goods that you use in your house over a thirty-day period so that you will know what to add to your disaster food storage plan.
How long does canned food last?
Some sources say canned food should last seven years, while others say that the nutritional value begins to deteriorate after only six months.
For the purposes of our discussion, shelf life will refer to the amount of time a product will maintain most of its nutritional value, texture, and taste.
You can expect canned vegetables to have a shelf life of more than two years.
If purchased fresh and stored in a consistently cool room below 70 degrees, it is possible that canned vegetables will last up to five years, while canned fruits may last from two to four years.
Canned tomatoes, though, do not store well because their acidity causes premature corrosion of the cans in which they are stored. Canned baby food generally has a shelf life of roughly two years if stored properly.
All of these foods may still be edible past these time frames, but the nutritional value will probably decrease.
What can go wrong?
Over time, it is reasonable to expect the cans to rust. Given enough time, this may allow tiny holes to form in the metal which can let contaminants in.
Canned foods are also adversely affected by temperatures over 100 degrees F. The higher the storage temperature, the shorter the shelf life. The best temperature for storing canned foods in an emergency supply is between 50 °F and 70 °F.
Cans should also be kept dry to prevent rusting, which shortens their shelf life as well.
The National Ag Safety Database says that:
Flood waters may carry silt, raw sewage, oil or chemical wastes.
Filth and disease-causing bacteria in flood water will contaminate food, making it unsafe to eat…
Commercially-canned foods are usually safe after being in flood waters if the metal can appears undamaged. But discard cans if they are rusty, creased, dented, crushed, bulging or have ends that spring in and out. The contents may be contaminated.
DO NOT TASTE.
All cans must be washed and sanitized before they are opened.
To sanitize the cans, remove the labels and wash them with a chlorine- or bleach-based solution.
If a can is bulging, spews liquid when you open it, or doesn’t smell quite right, do not eat the contents.
Botulism is a deadly food poisoning caused by the nerve toxins produced by the bacterium Clostridium botulinum, which can sometimes be found in expired or improperly canned foods
It isn’t the botulism bacterium that kills you, it’s the toxin that it produces as it grows. The Center for Disease Control says that symptoms of botulism include double vision, blurred vision, slurred speech, difficulty swallowing, dry mouth, and muscle weakness.
These symptoms are due to the muscle paralysis caused by the botulism toxin, and usually begin 18 to 36 hours after eating contaminated food. However, symptoms can occur as late as 10 days later.
How to can food at home
Home canning of fruit, vegetables, and even meat gives a unique sense of self-sufficiency, and many people even find canning to be their favorite hobby.
Other people feel that store-bought canned goods are so inexpensive that it just isn’t worth their time and effort to do home canning.
People who do their own canning, however, have a definite advantage simply because they know a potentially very valuable skill.
Home canning is actually done in mason jars. The idea is to kill the bacteria in the food with intense heat and deprivation of oxygen.
Pressures and times for canning different foods can vary greatly. Canning meat, for example, requires high pressures and different processing times than fruit or vegetables.
Most meat, vegetables, and other low-acid foods are canned in pressure cookers. The mason jars are sealed with vacuum canning lids and screw-tops and heated to 240 degrees F to kill botulism spores and other bacteria.
As altitude changes, so does the pressure and time required for the desired temperature. Refer to a good canning guide book for exact directions on the specific item you are canning. The book will also indicate expected shelf lives for various home canned foods.
Is home canning safe?
Home canning is completely safe as long as you follow the directions.
The best places to get instructions on safe home canning are the county extension office and the US Department of Agriculture.
You should also purchase the Ball Blue Book wherever you buy your canning supplies.
Pressure cookers come in lots of different kinds and sizes, but they all come with directions. If you don’t follow those directions properly, Clostridium botulinum bacteria can grow in the jars, producing a deadly toxin which you cannot see, taste, or smell.
You won’t know it until it is too late.
This bacterium loves the high pH (low acid) and low oxygen atmosphere present in sealed canning jars of food such as vegetables, meat, fish, and poultry.
The Clostridium botulinum spores themselves are not so bad, because they are actually all around us. You unknowingly ingest them everyday and they are harmless.
The problem is that when they are allowed to grow into vegetative cells, they produce a deadly nerve toxin that causes botulism, and that will kill you.
That is why you have to follow the directions precisely; to make sure that the canning process kills the spores before they can grow to the stage where they produce the toxin. You can’t shave any time off any of the steps or take any other shortcuts. If you do, it could prove fatal.
Canning in jars can have some other disadvantages. Being glass, the jars are susceptible to breakage. They need to be stored in boxes to keep the light from sapping the nutrients from the food inside. Unboxed jars are hard to stack. Jars can be expensive and the weight is considerable. The process is long, tedious, and requires strict attention to detail.
Canning fruits at home
More acidic food items are canned with a boiling water canner (which is the best way to can food without a canner). This method is sometimes used for canning fruits and making jellies because they tend to require less processing time and lower temperatures to kill deadly bacteria in the food.
This is also the preferred method for canning tomatoes and pickling vegetables.
A boiling water canner is basically a big water cooker with a lid that does not use pressure, only hot water. It also has a removable rack inside to improve water circulation and to keep the jars from bumping together and breaking.
Canned goods in a jar should have a vacuum-tight seal after the canning process. If this seal is lost at any time during storage, or if the lid is bulging, the food should be thrown out. Be sure and write the canning date on the lid with a Sharpie marker.