See Also: Shelf Life of Canned Food; A History of Canning; Can Trivia & Facts
EXTREME EXAMPLES of CANNED FOOD SHELF LIFE
The steamboat Bertrand was heavily laden with provisions when it set out on the Missouri River in 1865, destined for the gold mining camps in Fort Benton, Mont. The boat snagged and swamped under the weight, sinking to the bottom of the river. It was found a century later, under 30 feet of silt a little north of Omaha, Neb.
Among the canned food items retrieved from the Bertrand in 1968 were brandied peaches, oysters, plum tomatoes, honey, and mixed vegetables. In 1974, chemists at the National Food Processors Association (NFPA) analyzed the products for bacterial contamination and nutrient value. Although the food had lost its fresh smell and appearance, the NFPA chemists detected no microbial growth and determined that the foods were as safe to eat as they had been when canned more than 100 years earlier.
The nutrient values varied depending upon the product and nutrient. NFPA chemists Janet Dudek and Edgar Elkins report that significant amounts of vitamins C and A were lost. But protein levels remained high, and all calcium values "were comparable to today's products."
NFPA chemists also analyzed a 40-year-old can of corn found in the basement of a home in California. Again, the canning process had kept the corn safe from contaminants and from much nutrient loss. In addition, Dudek says, the kernels looked and smelled like recently canned corn.
The canning process is a product of the Napoleonic wars. Malnutrition was rampant among the 18th century French armed forces. As Napoleon prepared for his Russian campaign, he searched for a new and better means of preserving food for his troops and offered a prize of 12,000 francs to anyone who could find one. Nicolas Appert, a Parisian candy maker, was awarded the prize in 1809.
Although the causes of food spoilage were unknown at the time, Appert was an astute experimenter and observer. For instance, after noting that storing wine in airtight bottles kept it from spoiling, he filled widemouth glass bottles with food, carefully corked them, and heated them in boiling water.
The durable tin can--and the use of pottery and other metals--followed shortly afterwards, a notion of Englishman Peter Durand. Soon, these "tinned" foods were used to feed the British army and navy.
The canned food principle that won Nicolas Appert his prize of 12,000 francs has endured over the years. What might surprise Appert, however, is how his discovery is making food shopping and storing easier for the 20th century consumer.
Those who order coffee at fast food restaurants now also are served canned half-and-half, which has been transported and stored without concern about refrigeration. Hikers can take flexible pouches of canned food on backpacking trips without having to worry about saving water to reconstitute freeze-dried meals. And, in this society of microwave owners, Americans who don't have time to prepare a well-balanced meal can pick up a plastic container filled with a canned, nutritious dinner.
From: The Canning Process: Old Preservation Technique Goes Modern
by Dale Blumentha in FDA Consumer magazine, Sept 1990