310 PRESERVATION METHODS 



Draggett and Kensett. Other products followed with fishery products 

 such as salmon and crab being among the first. 



Although Isaac Solomon introduced the use of calcium chloride to 

 raise the temperature of the ''process" water to a high of 240°F in 1860, 

 it was not until 1874 that the real beginning of modern canning came with 

 A. K. Shriver's introduction of the pressure kettle or retorts Prior to 

 that time, all processing had taken place in boiling water, although Appert 

 had experimented with an autoclave in his original work. The canning 

 industry grew. The first canning trade association, formed in Baltimore 

 in 1872, was followed by a national association in 1890 which ultimately 

 influenced the adoption of the Pure Food Act of 1906. The National 

 Canners Association was formed the following year. 



From these meager beginnings the canning industry in the United 

 States has grown to giant proportions. According to the 1954 census 

 report^ over 3500 plants were involved in the canning, preserving, and 

 freezing industries, employing almost 200,000 people and producing prod- 

 ucts with a value approaching four billion dollars. While the canning of 

 fishery products is only a small portion of the total canning industry, in 

 1960 accounting for only 2.6 per cent of the total of 4.8 million tons of 

 metal consumed in ''tinplate" cans^ it is big business, producing products 

 in 1960 having a value of over 387 million dollars^ The canning of fishery 

 products is also a growing industry; from 1940 to 1960 product value 

 quadrupled. 



Containers 



Appert performed his original canning experiments in glass with spe- 

 cially designed cork stoppers. In 1810 an Englishman, Peter Durant, con- 

 ceived and patented the idea of using containers of glass, pottery, tin 

 (tinplate), or other suitable materials for canning. Not until 1900 was the 

 handmade, hand-soldered ''hole in cap" can replaced by the modern 

 "sanitary" or open top can of today ^ Initially, the "hole in cap" cans 

 were made at speeds of 60 cans a day by the expert tinsmith. Today the 

 can-making industry is one of the most highly automated industries in 

 the world, with round, open-top tinplate cans being manufactured at 

 speeds up to 1000 cans per minute. Can-making speeds of 400 cans per 

 minute are common. 



The vast majority of processed fishery products canned in the United 

 States today are packed in three-piece open top tinplate cans. Drawn 

 tinplate cans are used for sardines, mackerel, anchovies, and certain spe- 

 cialty items. Glass containers are not used in substantial quantities for 

 fishery products, other than for limited quantities of specialty products 

 and fish roe. 



