CHAPTER II* 

 HEAT IN THE PRESERVATION OF FOOD PRODUCTS 



HISTORICAL RESUME 



The principle involved in the preservation of food by heat may be 

 said to have had its origin in the experiments of Spallanzani, who in 

 1765 boiled meat extract for an hour and hermetically sealed the flasks, 

 after which treatment no change occurred in the material. An applica- 

 tion of this principle was suggested as early as 1782 by the Swedish 

 chemist, Scheele, who advised the exposure of vinegar in bottles to the 

 temperature of boiling water in order to effect its preservation. Some 

 years later the principle was applied to the conservation of food by a 

 French confectioner, Nicholas Appert, who in 1811 published an 

 exhaustive treatise on "The Art of Preserving Animal and Vegetable 

 Substances." His method was to enclose the food in a glass jar which 

 was then corked tightly, and placed in boiling water, the length of 

 time of heating varying with the article to be treated. 



In 1810 Peter Durand secured a patent from the English govern- 

 ment for the preservation of fruits, vegetables and fish in hermetically 

 sealed tin and glass cans. He did not claim to be the discoverer of the 

 process, but said it had been communicated to him by a " foreigner 

 residing abroad." Although the secret of the process was jealously 

 guarded, the employees of different establishments became familiar 

 with its essentials, and in this manner the industry found its way to 

 America. One of the first to introduce the process was Ezra Daggett, 

 who, with his son-in-law Thomas Kensett, in 1819 engaged in the manu- 

 facture of hermetically sealed goods, the principal foods packed being 

 salmon, lobsters, and oysters. In 1820, William Underwood and 

 Charles Mitchell, emigrant employees from a canning factory in England, 

 opened a factory in Boston where they canned plums, quinces, cran- 

 berries and currants. 



* Prepared by S. F. Edwards. 



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