14 CIRCULAR 2 7 8, U.S. DEPARTMENT OE AGRICULTURE 



carelessly during the picking and packing process. Overmature or 

 "weak" fruit is likely to pit and decay badly before the end of 2 

 months, even under the optimum conditions of humidity and tem- 

 perature mentioned above. 



The chief decays of grapefruit in storage are stem-end rot (on 

 Florida and Texas fruit), green-mold rot, and blue-mold rot; the 

 latter is frequently referred to as a contact rot because of its ability 

 to spread from a diseased fruit into a sound one touching it. Stem- 

 end rot is less destructive on grapefruit in storage than are the other 

 two because it is kept in check fairly well by cold-storage tempera- 

 tures. All three of the rots are more serious at the high humidity 

 it is necessary to maintain in order to keep pitting to a minimum, 

 hence care should be taken that the humidity does not become ex- 

 cessively high at any time. Frequent inspection is desirable through- 

 out the storage period, to determine the condition of the fruit with 

 respect to both pitting and decay. 



GRAPES 



VINIFERA 

 (Temperature, 31° to 32° F. ; relative humidity, 80 to 85 percent) 



Large quantities of the European or vinifera grapes, grown prin- 

 cipally in California, are stored every year. The most important 

 of the varieties stored are Emperor and Ohanez (Almeria). Olivette 

 de Vendemain, Malaga, Sultanina (Thompson Seedless), Flame 

 Tokay, and Eibier are occasionally stored also. All of these have low 

 freezing points, lower, in fact, than that of any other important 

 fruit, largely because of the high sugar content of grapes. Although 

 for most varieties there is no danger of freezing injury at tempera- 

 tures as low as 28° F. (5), they are usually held at temperatures of 

 31° to 32°. A humidity of 80 to 85 percent is desirable to prevent 

 wilting of the stems and fruit. 



California grapes for cold storage are packed in kegs or drums in 

 sawdust or in various types of lidded lugs with or without sawdust. 

 Good results are usually obtained, although if the fruit or the sawdust 

 is damp at packing time or becomes so in storage there is danger of 

 damage by mold. Mold may develop also if the grapes have been 

 handled carelessly and there are numerous cracked or loosened ber- 

 ries scattered through the pack. Varieties differ in keeping quality. 

 The best storage varieties, packed in sawdust, can be held 4 to 6 

 months at 32° F. Emperor and Ohanez seem to hold better than 

 any of the other storage varieties. Treating grapes with sulphur 

 dioxide before placing them in cold storage has been found helpful 

 in preventing decay. 



AMERICAN 



(Temperature, 31° to 32° F. ; relative humidity, 80 to 85 percent) 



The eastern or American varieties of grapes, the most important 

 of which is Concord, are not adapted to long storage and most of 

 them do not hold up well under storage conditions for more than 

 3 or 4 weeks. After that time they begin to deteriorate in flavor 

 and may suffer heavily from decay if the temperature is not kept 



