24 CIRCULAR 713, U. S. DEPARTMENT OF AGRICULTURE 



sides and bottom. After 6 hours at 60° all specimens showed 

 some injury but only in limited areas over the surface. No injury 

 was noted in the inner flesh. The outer wall, where affected, 

 showed a dark, water-soaked appearance on the surface and a 

 similar condition extending inward about an eighth of an inch. 

 Under light pressure the injured tissues readily exuded a watery 

 juice. When the squashes were left for 24 hours at 60° the injured 

 areas on the surface began to show mold growth. 



SWEETPOTATOES 



Sweetpotatoes in an unpapered %-bushel hamper were held in 

 an 18° F. room for 51 hours. After 5 days at 45° many of the 

 roots were soft and when cut were very leaky. The cut surface 

 did not exude a milky juice as normal unfrozen roots do. All roots 

 that were cut had a darkened band around the outside of the cross 

 section, extending inward one-eighth to three-sixteenths inch. 

 The flesh was mottled light gray to brown or reddish and had a 

 sour, off -smell. All roots in the hamper showed injury. 



Other tests showed that an exposure of only 3 or 4 hours to 22° 

 F. caused unprotected sweetpotatoes to turn brown inside. The 

 first region of the root to be injured is the ring of water-conduct- 

 ing tissue about one-sixteenth to one-eighth inch under the skin. 



Tomatoes 



Tomatoes in an unpapered, lidded 30-pound lug were held in an 

 18° F. room for 48 hours. After 6 hours no freezing could be de- 

 tected, but after 7 hours a few fruits next to the lid were begin- 

 ning to freeze. On removal from the freezing room all tomatoes 

 around the outside of the mass of fruits were found frozen hard, 

 but those in the center layer, away from the sides, ends, bottom, 

 and lid, were still unfrozen. These comprised about one-quarter 

 of the total number of tomatoes in the lug. When the frozen toma- 

 toes thawed at 45°, they become soft, watery, and worthless. 



Unprotected tomatoes laid out singly in the same freezing room 

 began to freeze on the outside in about 3 hours. After 6 hours the 

 freezing extended inward about one-half inch from the surface of 

 each fruit. 



Turnips 



Turnips were held in a bushel basket in a 24° F. room for 144 

 hours. The basket was papered over the sides and bottom, and 

 paper was also laid loosely over the top. Freezing temperatures in 

 the turnips were recorded after 19 to 21 hours, but no injury was 

 found when frozen roots were removed and thawed. The basket 

 was, therefore, left in the freezing room for 6 days in order to 

 obtain injury. 



Thirty-six hours after removal from the freezing room (12 

 hours at 32° F. after being held for 24 hours at about 60°) those 

 from the top of the basket were dirty gray on the outside, soft, and 

 w T ater-soaked and had a fermented smell. The skin had a blistered 

 appearance produced by the formation of small lens-shaped masses 



