STERILIZATION. 13 



The first direct application of bacteriological methods to spoilage 

 problems in canning in this country seems to have been made by 

 II. L. Russell, of Wisconsin, in 18D5. 1 He investigated the cause of 

 swells in peas and found it to be due to bacteria as a result of in- 

 sufficient processing. The Wisconsin packers were processing the 

 peas at 230 F. for from 10 to 11 minutes, and were having heavy 

 losses. He advised, as a result of his experiments, that the tempera- 

 ture be raised to 242 F. and maintained for 15 minutes, which caused 

 a cessation of the trouble. 



In 1896 Prescott and Underwood 2 began the study of swelled and 

 soured corn, and later turned their attention to soured peas. Their 

 first results were published in 1898. In that year they gave the first 

 of a series of addresses before the National Canners' Association, 

 which had a most marked effect in establishing canning on a scientific 

 basis. They identified the bacteria causing spoilage in corn and peas, 

 determined the thermal death points, the degree of heat attained in 

 the center of cans, and the time required to attain it. 



In 1897 the Canadian Government caused work to be done on 

 spoilage in canned lobster, or black lobster, as it was called. It was 

 determined that it was due to bacteria. 



In 1903 Harding and Nicholson, 3 of the New York Experiment 

 Station, studied the swelling of peas; they gave additional descrip- 

 tions of the organisms, and, as a result of their experiments, recom- 

 mended that the process be changed to 240 F. for 30 minutes. 



Since 1900 there have been numerous contributions on the organ- 

 isms causing spoilage. These usually deal with one particular prod- 

 uct or some special phase of bacterial activity. There has been no 

 systematic effort made to classify the organisms, to determine their 

 relation to different products, the kind of spoilage produced, nor the 

 exact methods of dealing with each. Several large packers employ 

 experts to work out their own problems, but hold the results secret. 

 It is evident that in the preparation of food there is a rich field for 

 scientific research, with great possibilities for valuable and practical 

 results. 



MODERN METHODS OF STERILIZATION. 



Sterilization may be accomplished by heat below, at, or above the 

 boiling temperature, depending upon the length of time the heat is 

 applied and the number of applications made. It is not practicable 

 to sterilize all foods in the same way because of injury to quality 

 or prohibitive expense. Sterilizing below the boiling point is feasible 

 only for a few products, principally fruits, and then is advisable 



1 Wisconsin Agr. Exper. Sta. Report, 1895, pp. 227-231. 



2 Technological Quarterly, 1898, pp. 6-11. 



'New York Agr. Exper. Sta., Geneva, 1903, Bui. 249. 



