Bruise testing was performed with three lots of bruise-free apples. 

 One lot consisted of relatively soft apples, averaging only 9.5 pounds by 

 pressure test. Even with such soft fruit, bruising was found on only 6.4 per- 

 cent of the apples tested. Slight bruising totaled 5.1 percent, and 1.3 per- 

 cent of this fruit was bruised moderately. No bruising was found in 

 93.6 percent of the apples. 



The second lot tested had a firmness of 14.5 pounds. Bruising amounted 

 to 4.9 percent, of which 4.7 percent was slight, and 0.2 percent moderate. 



Relatively firm fruit at 15.5 pounds by pressure test showed only 

 2.1 percent of the apples to be bruised, and this bruising was all slight. 



Complete line for U. S. Extra-Fancy and U. S. Fancy grade apples . --Bruise- 

 free fruit was run over the entire line in two different tests. Beginning 

 with the dumper, apples moved across the leaf eliminator, over the sorting 

 table, into the singulator and sizer, and out onto distributor belts and the 

 return-flow belto They were left on the return-flow belt for 2 minutes, then 

 recovered and set aside to be examined after 24 hours at room temperature. 

 Lot No. 1 had an average firmness of 17 pounds, and after 24 hours 1.4 percent 

 of the apples were bruised. Lot No.- 2 tested 14.5 pounds, and showed 2.3 per- 

 cent bruising. In both cases, the bruises were all slight. 



Conclusions 



Bruise testing was done with fruit that had been in controlled-atmosphere 

 storage for 6 months, as well as with fresh-harvested fruit. Apples used in 

 the tests had firmness indices that ranged from 9 to 17 pounds, permitting the 

 effect of firmness (or softness) to be studied. 



Importance of fruit firmness at the time of handling is illustrated by 

 the results of tests conducted on the same component of the line, but with 

 fruit of different firmness. In every case, the softer the fruit the more it 

 was bruised. 



The dumper and utility grade disposal belt caused the most bruising, and 

 the sorting table the least. Bruising on the return-flow belt was proportional 

 to the length of time apples were on the belt and the number of revolutions 

 they made. Large fruit bruised more easily than small fruit. All this 

 suggests that apples should not be left on the return-flow belt any longer 

 than necessary—particularly the large apples. It would probably be better to 

 stop the line occasionally and clean off the belt rather than leave fruit 

 rotating on the return-flow belt. 



The automatic box fillers had a remarkably low bruise count, which shows 

 that even tender apples can be jumble-packed mechanically without excessive 

 bruising. 



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