120 S. C. PRESCOTT 



of the environment on the bacteriological character of the foods 

 themselves. Four types of storage conditions were employed. 

 The first is called "severe," since the chamber used was kept at 

 37°C. and the relative humidity at 100 per cent. The second was 

 "moderate" in character, the temperature being 20° to 25°C. with 

 a relative humidity of about 70 per cent. Third, "favorable" 

 storage, with chamber maintained in one case at ordinary tem- 

 perature and in another at 37°C. but with no artificial humid- 

 ification. In both, the relative humidity was approximately 50 

 per cent. This condition represents fairly well the conditions 

 which may be met in ordinary transportation and commercial 

 handling. The fourth condition employed was "cold storage" 

 at 0°C. and about 95 per cent relative humidity. 



Six weeks was taken as the maximum period of storage under 

 the various conditions with the first set of products. Examina- 

 tion of the products was made at the end of each two weeks. 



Since this study is a combination of the sanitary and the com- 

 merical or industrial phases of the subject, we have deemed it 

 desirable to use as containers for the material under investigation 

 a variety of the newer types of treated paper cans or cylinders 

 as well as tinplate and glass. It is obvious that in tightly stop- 

 pered glass containers and in tin cans sealed or tightly closed by 

 friction tops, there is no noteworthy opportunity for additional 

 moisture to gain entrance. Any changes in the food product 

 must therefore be the result of bacterial or enzymic action taking 

 place at low moisture percentage. With the paper containers, 

 on the other hand, the exclusion of moisture is far from perfect, 

 even in those holders treated by paraffin, waxes, etc., to secure 

 impermeability. Statements are often made that ordinary paper 

 bags will serve to preserve dried vegetables and fruits, and while 

 this is often true if storage conditions are dry and temperature 

 low, it is on the other hand, often fallacious, especially in damp 

 climates and with vegetables containing sugars or other hygro- 

 scopic ingredients. 



Without going minutely into the methods of experimentation 

 which have been followed, I wish to place before you the general 

 results obtained. 



