116 S. C. PRESCOTT 



food materials and the various food compounds and substances 

 which were brought to the Surgeon General's Office for exam- 

 ination. Among these were the dehydrated vegetables which 

 were later purchased in considerable quantity and used by our 

 forces on the other side. Although the quantity actually used 

 was small as compared with the total food supply, you may be 

 interested to known that something like forty thousand tons 

 were sent over. In connection with investigations on this sub- 

 ject, I thought it desirable to make certain bacteriological studies 

 of these foods, which I wish to report upon at this time. 



Dehydrated vegetables generally contain less than 10 per cent 

 of water. They have often been subjected to a pre-treatment by 

 hot water or steam and to more or less thorough washing. The 

 drying temperatures vary from 130° to 185°F. (55° to 85°C.) with 

 different processes, and the heating period is of 3 to 24 hours' 

 duration, although rapid evaporation may considerably reduce 

 this during a portion of the time. 



It may be further noted that these dehydrated substances will, 

 when soaked in water, reabsorb the water which has been lost 

 and assume the normal condition of the tissues. On the central 

 table there are some specimens of dehydrated products which 

 have been restored by simply adding water, and at the end of this 

 meeting I should be very glad to have you examine the dried and 

 restored substances as they appear there. 



The presence of bacteria in or upon dehydrated vegetables 

 may therefore be of some interest. They may be: 



1 . Organisms originally on food which have survived the proc- 

 ess (and perhaps increased). 



2. Organisms gaining access from wash water, handling in raw 

 state, or utensils. 



3. Organisms deposited on surfaces during packing, handling 

 in dried state, or utensils. 



Studies on a large number of samples of dried foods have shown 

 very few, if any, of them to be sterile, although often the numbers 

 of bacteria present were very small. Moreover, long continued 

 keeping under suitable conditions causes the number to decrease 

 gradually. Mold spores were commonly present, but yeasts 



