INTRODUCTION 2J 



the foods so prepared are entirely free from living bacterial infection 

 of all kinds. This is true of some foods but not by any means of 

 all of them. Dr. W. A. Sawyer, Director of the California State 

 Hygienic Laboratory, in reporting upon an epidemic of 93 cases of 

 typhoid fever (at Hanford, California) due to a single carrier, 

 traced the source of the infection to cooked Spanish spaghetti, 

 prepared by the typhoid carrier. The following tests were made 

 in the California State Hygienic Laboratory to ascertain the effects 

 of baking on the presence of typhoid fever germs in the interior of a 

 mass of spaghetti. 



"A large hot-air sterilizer was heated and kept between 160 

 and 170 C. (320 and 338 F.). The pan of spaghetti was in- 

 troduced and subjected to this heat for 30 min. When the dish 

 was removed the surface was of a golden brown color. The ap- 

 pearance and aroma suggested that the spaghetti was thoroughly 

 cooked and very hot. The temperature near the top was 54 C. 

 (129.2 F.) and at the middle, 23 C. (73.4 F.). Ten minutes 

 later the temperature at the middle was 24 C. (75.2 F.) and the 

 dish was then returned to the oven. Cultures taken at various 

 levels showed that the typhoid bacilli were alive even close to the 

 surface. 



"In the next baking the oven was kept at temperatures ranging 

 between 207 and 214 C. (405 to 417 F.). After half an hour 

 the pan was removed. The surface was dark brown and the 

 points sticking up from it were charred. The liquid around the 

 margin was boiling vigorously and the whole dish was sizzling. 

 The temperature just under the surface was 83 C. (181.4 F.). 

 At the middle it was 28 C. (82.4 F.) and near the bottom it 

 was 48 C. (118.4 F.). An hour later the temperatures had be- 

 come nearly equalized and were 46 C. (114.8 F.) near the top, 

 42.5 C. (108.5 F.) at the middle, and 43 C. (109.4 F.) near the 

 bottom. This showed that the interior of the dish did not reach 

 even a pasteurizing temperature. 



"Cultures taken at the surface soon after the pan had been 



