Canned Food Safety: Are They Good For You?

Canned food safety: Canned foods are quick and convenient, but are they nutritious? This article looks at the canning process to ease your mind about eating canned foods.

Canning was invented long before nutrition was discovered. In days gone by, it was more important to have enough food at all times. No one even knew about vitamins and minerals then. But they did know that food went off very quickly unless you dried it or pickled it.

In the early 19th Century, the French Government was desperate to find a way of feeding its armies. So it issued a challenge to its citizens to find a new way of preserving food.

The man of the moment was Nicolas Appert, a confectioner. He discovered that if you put food into a glass bottle, boiled it for a certain amount of time, and then sealed the bottle, the food inside wouldn't go off. The method worked just as well for meats as for fruits and vegetables. He published his findings in 1810, but he had no idea at all why his method worked. He just knew that it did. You took out the air, you applied heat, and the food remained edible.

The problem with glass, of course, is that it breaks. So an Englishman named Peter Durand had the idea of using tin cans instead. By 1839, it was quite common to preserve food in tins.

And still nobody knew exactly how or why it worked.

And then came Louis Pasteur. He found out that tiny microbes caused food to go off. He also found that if you applied heat to the microbes, they died. Without air, new microbes could not take their place. The term pasteurization comes from Pasteur's scientific discovery.

Today, we know that a number of factors cause food to go off. Microbes are one of them. Enzymes, oxidation and dehydration are the others. The canning process eliminates all these factors.

But what does removing air and applying heat do to the nutritional value of foods? Here's what scientists have found.

Canning has no effect on proteins, carbohydrates and fats. If you can meat, for example, it will have the same amount of protein and fat after canning as it had before.

Exposure to air destroys Vitamin A. If you remove the air, even if you heat the food, the amount of Vitamin A in the food stays much the same. So canning hardly affects Vitamin A.

Exposure to heat usually destroys Vitamin C, but only in the presence of air as well. If you remove the air, the amount of vitamin C in the food remains much the same.

Neither does canning appear to affect vitamin B2. But it does have some effect on vitamin B1. If the food containing vitamin B1 is very acid, the amount of vitamin B1 stays much the same. If it is not very acid, canning it safely needs higher temperatures for a longer time, and then not much vitamin B1 remains.

In general, canning does not seem to affect the nutritional values of food very much. From that point of view, you need feel no guilt about turning to a can for a quick and convenient meal! Your fresh vegetables can lose more vitamins by lying in storage rack for a week.

There are other factors to consider. Remember that food is canned raw, and heating cooks it. A good cannery will make sure that the raw food is fresh and absolutely clean. Usually, cleaning means either washing it thoroughly, or blasting it with air to remove unwanted particles of sand or grit. If you do have problems with contaminated food, the problem lies with company canning the food, and not the canning process as such. If your canned food has grit or other strange bits in it, don't buy that particular brand ever again.

Sometimes a technical hitch can cause contamination in a particular batch of cans. For this reason, always check your cans carefully before opening them. They should be completely airtight. If your can bulges, take it back to the store where you bought it and get a refund or a replacement. A bulging can indicates infection by microbes and the food in that particular can is not safe to eat. Don't feed your pets food from bulging cans either.

Even if the can doesn't bulge, but you hear a hiss when you open it, rather be safe than sorry and throw the food away. Make a note of the batch number on the tin itself, so that you can give it to the manufacturer when you phone to complain. A reputable company will almost certainly want to withdraw that entire batch from circulation.

Finally, remember that what is canned is more important than the canning process itself. Read the labels on your cans and look for ingredients that you consider unhealthy or that have a bad effect on you. All the canning in the world can't turn a bad food into a good one!

Generally speaking, canned foods are just as good for you as the uncanned version of the same food. Just be sure that your can is airtight and that you buy foods from a company that you trust.

© High Speed Ventures 2011