54 



CIRCULAR 74 0, U. S. DEPARTMENT OF AGRICULTURE 



An operator needs to know core temperatures of the fruit, especially 

 in parts of the room where cooling is difficult. Periodic observations 

 of fruit temperatures will indicate what methods of stacking and air 

 distribution will give best results and what parts of the room need 

 special attention. Reliable thermometers or thermocouples are nec- 

 essary for this purpose. An investment in equipment for obtaining 

 accurate records of temperature in all parts of a storage is worth 

 while. 



Frequently when actual fruit temperatures are measured the 

 results are disappointing. If they are it is sometimes possible to 



improve conditions 

 "] markedly with little 

 cost or inconvenience. 

 In any case, it is to an 

 operator's advantage 

 to know just how 

 quickly he can cool the 

 fruit and how uniform 

 he can hold the tem- 

 peratures after it is 

 cooled. 



In addition to the 

 management's respon- 

 sibility to ascertain 

 whether core tempera- 

 tures are what they 

 should be in all parts 

 of the cold-storage 

 plant, there is the fur- 

 ther responsibility of 

 checking on fluctua- 

 tions in temperature 

 during the operating 

 season. This is best 

 done by the continuous 

 operation of a record- 

 ing thermometer, or 

 thermograph, at a cen- 

 tral point in each 

 room. One type of 

 such instrument is il- 

 lustrated in figure 23. A file of temperature records affords the man- 

 agement a protection against complaints of grossly irregular tempera- 

 tures, but does not insure optimum core temperatures at all positions 

 throughout the stored fruit. 



Figuee 23. — Recording thermometers are useful for 

 giving temperature fluctuations and providing a 

 permanent file on cold-storage performance. 



MAINTAINING HUMIDITY 



Periodic determinations of the relative humidity in storage rooms 

 are necessary to avoid atmospheres that are relatively dry and likely 

 to cause subsequent shriveling of the fruit. Several types of instru- 



