8 BULLETIN 1335, U. 8. DEPARTMENT OF AGRICULTURE 
Machines for seeding raisins and dried prunes have been developed 
to a satisfactory degree. They consist of a gang of toothed disks 
much like circular saws, which rotate against a rubber-covered 
cylinder, revolving in the opposite direction, and force the seeds 
between the disks. The seeds that remain mixed with the fruit are 
then automatically separated on a shaker. The fruit is softened by 
cn or hot-water processing before being passed through the 
seeders. 
TRAYING 
After the raw material has been prepared in the desired form, no 
time should elapse before traying and subsequent treatments pre- 
liminary to its being placed in the drier. No definite rule can be 
given in determining the quantity of material to be placed on a unit 
area of tray surface. Experience will soon show the operators how 
much will insure equal pretreatment and even, rapid drying. Many 
of the larger fruits should be trayed only one layer deep. 
Trays should be light but capable of withstanding strain, and they 
should permit a maximum exposure of the materials. Trays of the 
type most often seen have a spreading surface formed either of wire 
screen or wooden slats held firmly in a narrow but rigid wooden or 
metal frame. Many of the trays now in use have been employed in 
sun or other drying. If new trays are made, however, the ‘‘one- 
man” tray, about 214 to 3 feet square, is most convenient. 
Galvanized-iron, aluminum, and monel-metal screening have been 
tried with varying degrees of success. The galvanized-iron screen- 
ing is the most practical at present, considering initial costs, repairs, 
and effect upon the material. Aluminum and monel metal have 
possibilities that merit further study. 
Wooden-slat trays can be more cheaply constructed than wire- 
screen trays, but they havea high rate of upkeep. These trays, how- 
ever, are not affected by sulphur fumes or fruit acids, for which 
reason they are preferred for most fruits. 
CONVEYING THE TRAYED MATERIAL 
The trucks for conveying loaded trays are of two general types. 
In one type a skeleton frame is provided with cleats, upon which the 
trays rest. The cleats are from 2 to 4 inches from center to center 
above one another. These trucks are made of various combinations 
of wood or angle iron. The other type, which may be called the 
stack type, has a low floor supported by wheels 3 to 5 inches in 
diameter. The trays are piled or stacked one above the other, and 
the desired space between them is maintained by the raised sides of 
the trays. Various alterations may be made for convenience in 
handhag and loading. 
PRETREATMENT 
The original method of preparing fruits and vegetables for drying 
consisted in washing, peeling when desirable, cutting, and traying. 
By this method most dark-colored materials made fairly presentable 
dried foods, but light-colored fruits and vegetables did not. The 
attempt to overcome this difficulty led to the introduction of blanch- 
ing, or processing, and sulphuring. 
