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Canned Foods, BPA and Safety Tips

Tim Boyer's picture

Recent news reports tell us that canned foods - canned soup in particular - may not be as safe as previously believed because of a study that reports the discovery of high levels of BPA in the urine of test subjects eating canned soup in comparison to test subjects who ate fresh soup. While further study is needed to determine the true risk of eating canned foods, canned foods have a history of saving lives rather than harming lives. This article takes a brief look at the history of canned food and provides a few safety tips to keep in mind before opening that next dust-covered can of food from your pantry shelf.

If necessity is the mother of invention, then war is the hammer of its industry. Previous to the invention of canned foods, soldiers either had to buy foods from local markets, steal from nearby farms or go hungry. During his military campaigns in the late 1700’s, Napoleon is credited with the phrase “An army marches on its stomach.” His statement indicates both the importance and difficulty in keeping armies fed during times of war. One estimate has it that it took 30-40 tons of food per day to feed Napoleon’s Northern Italian army in 1795. Food preservation at the time was limited to smoking, drying and curing in salt, which left the food selection limited as well as poor in nutrition.

A result of the necessity for food that would not perish during a military campaign was a 12,000 franc award from the French government to the person who could devise a way to preserve food. The prize was eventually earned by a French chef named Nicolas Appert who in 1795 began experimenting with a wide variety of methods to preserve foods. He discovered—approximately 50 years before Louis Pasteur’s discovery that germs were responsible for food spoilage—that by heating foods to a high temperature in glass jars that were sealed with cork and wax resulted in preservation that would last many months. Appert published his discovery in a book titled “The Art of Preserving Animal and Vegetable Substances” and won the 12,000 franc prize.

Shortly after Appert’s discovery, improvements were made using metal cans to preserve food rather than glass jars. In 1812 the first commercial cannery produced canned foods in containers consisting of iron plated with tin. Oddly enough, it was roughly another 40 years before the can opener was invented.

Throughout the 1800’s, canning methods improved and the variety of produce and meats widened as well as the availability of canned goods. Unfortunately, however, the availability of canned foods came too late for the doomed Donner Party that spent the winter of 1846 trapped in the Sierra Nevada on their way to California. The Donner Party story is well-known for its reports of surviving pioneers having resorted to cannibalism while trapped in the snow.

Reportedly, Gail Borden, an inventor and businessman was motivated by the Donner story and turned to finding ways of creating preserved food for long journeys and expeditions. One brief success he had was with a beef biscuit that he sold to the U.S. Army and to Dr. Elisha Kane for an arctic expedition in the 1850’s. However, his greatest and longest lasting success is the Borden Condensed Milk that we can still buy today at the supermarket.

Other food brand names that owe their legacy to the invention of canned food needed in times of war include the popular WWII products SPAM, Van Camp’s Pork and Beans, and Underwood Deviled Ham.

More recently, however, the history of canned foods is taking a potentially dark turn. Researchers from the Harvard School of Public Health have released their findings that just five days of one serving of canned soup can increase a person’s urinary bisphenol A (BPA) levels by more than 1000 percent. BPA is a known endocrine disruptor that increases the risk of delayed puberty and has been linked to cancer and obesity. BPA is an industrial chemical used to make several plastics and as an epoxy resin for coating cans used in canned food and beverages.

While canned food products were previously suspected of being a source of BPA detected in urine samples throughout the world, the extent of the contribution of BPA from canned foods was surprising to the researchers of the study. A previous study showed that BPA is ubiquitous and was detected in 93 percent of the population above the age of six.

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“The magnitude of the rise in urinary BPA we observed after just one serving of soup was unexpected and may be of concern among individuals who regularly consume foods from cans or drink several canned beverages daily. It may be advisable for manufacturers to consider eliminating BPA from can linings,” said Karin Michels, senior author of the study.

The authors of the study also state that the levels of urinary BPA may prove to be only temporary and that more studies are need to determine how long the exposure lasts and whether it poses a significant risk.

So for now, canned foods are considered to be relatively safe, especially in comparison to the higher risk of eating contaminated food that may have spoiled during storage. The following is a list of safety tips to ensure that your canned food is stored correctly and is safe for consumption:

• Store cans in a cool, clean and dry area where temperatures are below 85 degrees. Temperatures up to and above 100 degrees Fahrenheit are harmful for canned foods and sharply increases the risk of spoilage. The preferable temperatures are between 50-70 degrees Fahrenheit. Also, do not freeze canned foods.

• Rotate the older canned goods to be used first. Label your cans immediately after buying with tape and a marker to see dates easily.

• Canned seafood must be used within 12 months. Canned meat and poultry will keep for 2 to 5 years if the can remains in good condition and has been stored in a cool, clean, dry place.

• High-acid canned foods must be used within 6-8 months. The natural acids from some foods can react with the metal in the can, especially with high-acid foods like tomatoes and pineapples.

• Fruit juices in a can may be stored up to 3 years, but should be monitored for signs of spoilage.

• Read the instructions given on the can for information on storing the food under the correct conditions.

• Toss out any cans that are dented or bulging.

Source: Harvard School of Public Health Press Release http://www.hsph.harvard.edu/news/press-releases/2011-releases/canned-soup-bpa.html