In 1810 confectioner Nicholas Appert published in Paris L'art de conserver, pendant plsieurs années, toutes les substances animales et végétales. . . . In this small book Appert described the first workable process for canning foods, laying the foundation of the food-processing industry. Appert's method, which he began working on in 1795, involved heating food and sealing it hermetically in specially made glass jars. By providing the first reliable way to preserve many types of prepared foods for extended periods of time, Appert also developed a new way of furnishing potable, nourishing and unspoiled food to armies in the field.
In 1800 Napoleon, who is widely quoted, accurately or not, as saying, "An army marches on its stomach," offered an award of 12,000 francs to anyone who could devise a practical method for food preservation for armies on the march. The award went to Appert, but since the method was considered to be of strategic importance for Napoleon's military campaigns, Appert was not allowed to publish it until 1810.
Hook & Norman, The Haskell F. Norman Library of Science and Medicine (1991) No. 59.