Canning is a method of preserving food by first heating it to a temperature that destroys contaminating micro-organisms, and then sealing it in air-tight jars or cans. Because of the danger of botulism, the only safe method of canning most foods is under conditions of both high heat and pressure, normally at temperatures of 240-250°F (116-121°C). Foods that must be pressure canned include all vegetables, meats, seafood, poultry, and dairy products. The only foods that may be safely canned in a boiling water bath (without high pressure) are highly acidic foods like fruits, pickled vegetables, or other foods to which acid has been added.
According to reseachers, canned tomatoes contain higher quantities of lycopene, an essential phytochemical, than fresh tomatoes.
Canning was invented in 1809 by the French confectioner Nicholas Appert. The process proved moderately successful and was gradually put into practice in other European countries and in the United States. Based on Appert's methods of food preservation the packaging of food in sealed airtight tin-plated wrought-iron cans was first patented by an Englishman, Peter Durand, in 1810.
A number of inventions and improvements followed, and by the 1860's, the time to process food in a can reduced from six hours to 30 minutes. Thomas Kensett established the first U.S. canning facility for oysters, meats, fruits and vegetables in New York in 1812 and also patented an improved tin canister method. Canned foods were soon commonplace, and today tin-coated steel is the material most commonly used. Some food firms are currently dabbling with self-heating cans.
Hirzel Canning Company & Farms
Contadina Foods, Inc
BOBOLI Pty. Ltd
Crown Holdings Inc
Silgan Containers Corporation
Can Manufacturers Institute
Packaging Machinery Manufacturers Institute
Recent development in canning industry (http://www.washingtonpost.com/ac2/wp-dyn/A37489-2004Oct16?language=printer)
For cans, to secure the hermetic seal an appropriate sealing compound is applied to the inside of metal can ends at the curl; and for glass jars the sealing compound is applied to the metal closures during container lid manufacturing.
Can Lifter or Base Plate: a round plate which lifts the can and can end to the seaming chuck and applies upward pressure during the seaming cycle.
Can seam guidelines (specifications) are provided to the low acidcannedfood manufacturer by the supplier of the container and end being used.
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