118 MISC. PUBLICATION 5 4 0. U. S. DEPT. OF AGRICULTURE 



sufficiently dry so that as little absorption of moisture as possible 

 occurs during packaging. In a dehydration plant with a capacity of 

 30 tons daily, one man does all the work from the end of the picking 

 belt through the stacking of the cases. 



Dehumidification of the air in the finishing and packaging room 

 may be necessary. When exposed to air any dehydrated fruit or 

 vegetable tends to increase or decrease in moisture content until it 

 finally reaches an equilibrium content which is typical for that 

 product and that relative humidity (table 9). Operators should con- 



Table 9. 



-Selected data 1 : Equilibrium moisture content of various dehydrated 

 foodstuffs 2 



Product 



Moisture Tempera- 

 content ture 



Relative 

 humidity 



Percent 



Apples . 



Apricots 



Cabbage 



Carrots 



Eggs, whole 



Flour, wheat, 83 percent patent. 



Milk, whole, 53 percent fat 



Milk, skimmed, 1 percent fat___ 



Peaches 



Pears 



Potatoes, white 



Potatoes, sweet 



Prunes 



Raisins. __ 

 Spinach.-. 

 Tomatoes. 



Room 

 Room 



Room 



Room 

 99 

 99 

 99 

 77 

 77 



! • 



S| r™, I 



Room 

 99 

 99 



48 

 62 

 10 

 29 

 52 

 12 

 40 

 75 

 32 

 44-50 

 50-70 

 16 

 24 

 38 

 56 

 66 

 49 

 63 

 72 

 22 

 38 

 19 

 36 

 62 

 35 

 58 



i See Anker, Geddes, and Bailey (3); Makower and Dehority (30); Schwarz (40); and Supplee (4£). 

 2 Data on dehydrated milk are significant in the storage and packaging of some soup mixtures, and data 

 on eggs and flour are of interest for the sake of comparison. 



sider carefully the advisability of dehumidifying the finishing and 

 packing room in all cases where the moisture content at shipment 

 corresponds to a relative humidity which is less than that which will 

 occur in the packing room at any time of the year or of the day. This 

 is important in handling leafy products and is most important when 

 products of 3 percent moisture content or less are ground. The 

 United States Weather Bureau publishes data on dew points which 

 may be expected in various parts of the United States. If the prob- 



