BACTERIOLOGICAL 'ASPECTS OF DEHYDRATION 119 



The molds isolated were identified as of the following genera: 

 Aspergillus, Mucor, Penicillium, Spicaria, Sporotrichum, Tricho- 

 derma, Herpocladiella. 



At least two species of Mucor, two of Penicillium and five of 

 Aspergillus were isolated. These are all organisms which may 

 be found on fresh vegetables or fruits. Probably the spores 

 survive all pretreatment and dehydrating processes. 



From the standpoint of numbers and types of bacteria, these 

 dehydrated products have the same characteristics as raw fruits 

 and vegetables, except that the number of organisms has been 

 greatly reduced by the processes to which the foods have been 

 subjected. 



STORAGE OF DEHYDRATED PRODUCTS AND EFFECT OF STORAGE ON 

 BACTERIAL CONTENT 



The practicability of dehydrated foods must depend largely 

 on whether they may be held in storage for long periods without 

 undergoing any deteriorations. If, as has been claimed, they 

 may be kept under all kinds of conditions if properly sealed, their 

 great usefulness is unquestioned, but the type of container be- 

 comes of supreme importance. To determine this point an ex- 

 tended study has been made during the past two years to deter- 

 mine the effects of various conditions of storage on the quality 

 of the product. 



As the preservation of dehydrated vegetables depends upon the 

 inhibitive effect of their low moisture content upon any destruc- 

 tive bacteria or other organisms which may be present, it is 

 obvious that the greatest difficulty of preservation would occur 

 where the products were exposed to a high relative humidity, per- 

 mitting them to absorb moisture and at the same time exposed to 

 a temperature which was most favorable to the growth of organ- 

 isms after the inhibition of a low moisture content was removed. 

 Consequently, in order to subject samples of the dehydrated 

 foods to the severest conditions they would be likely to encounter 

 in transporation, storage, or as merchandise, a series of investi- 

 gations was carried out with the purpose of determining the effect 



