determined bruising of Golden Delicious apples during 

 grading and packing that we described earlier. 



The bagging operation is a point of special concern, 

 since it causes so much impact bruising. The high impacts 

 (Figure 1) resulted from bags being dropped onto a con- 

 veyor in front of the closing machine, the snapping action 

 of the bag-dosing mechanism, the transfer points on the 

 conveyors leading, and the hand placing of bags into 

 shipping cartons. 



Much of this impact bruising during bagging can be 

 eliminated. The authors clearly showed this when they 

 placed a piece of shag carpet (facing up) between a 

 conveyor belt, onto which the bagged apples fell, and its 

 steel backing. The Instrument Sphere was dropped differ- 

 ent distances onto the belt, with and without the carpet 

 backing, and the padding reduced impact of the instrument 

 by nearly 75%. 



Instrument Spheres were also used in a transportation 

 study. They were placed in the top tray of a tray-pack 

 carton, and into 3-lb. bags in a carton. The cartons were 



transported from the packing house to a distribution 

 center, and then to a retailer, by a commercial semi-trailer. 

 As the trailer peissed over bridges under repair, impacts 

 were 3-times greater (54 vs. 17 g's) in the trays than in the 

 bags. Apparently, the tight fit in the bags provides protec- 

 tion to the fruit during rough transit. Note, however, that 

 velocities of these impacts during transport were much 

 lower than many of those experienced by apples on the 

 grading line (Figure 1). 



The Instrument Sphere developed by these research- 

 ers appears to have much value in assessing the sources of 

 impact bruising on harvested fruit. This particular study 

 re-emphasizes the high potential for bruising apples dur- 

 ing the mechanical grading and packing processes, and the 

 fact that much of this bruising need not occur. We urge 

 readers to review the causes of fruit damaged outlined in 

 the previous article evaluate their own packing lines for 

 sources of impact bruising, and take corrective actions. 

 Bruising is preventable . 



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Apple Bruising. III. Impact Bruising 

 Leads to Fruit Rotting 



William J. Bramlage 



Department of Plant & Soil Sciences, University of Massachusetts 



In previous articles [Fruit Notes 53(4):15-17 and this 

 issue pp. 6-7], we have examined findings on sources of 

 bruising to apples from studies conducted at Michigan 

 State University. Here, we shall use their findings to show 



a consequence of this bruising fruit rotting after 



packaging. 



This study was reported by C. L. Burton, Nancy L. 

 Schulte Pason, G. K. Brown, and E. J. Timm in a paper 

 entitled, "The Effect of Impact Bruising on Apples and 

 Subsequent Decay Development," presented to the 

 American Society of Agricultural Engineers on December 

 15-18, 1987. The authors are researchers in the Agricul- 

 tural Engineering Department and the U.S. Department 

 of Agriculture, Agricultural Research Service, at Michigan 

 State University, East Lansing. 



Blue mold, caused by Penicillium expansum Lk. ex 

 Thorn, is responsible for 80 to 95% of the rotting of apples 

 that is seen in commercial markets in the U.S. Contami- 

 nation with spores of this fungus can occur in the orchard, 



but most of it probably arises in the packing house, espe- 

 cially in water dumps and on grading and packing equip- 

 ment. Fruit contaminated during these operations may rot 

 quickly if the spores are able to penetrate the fruit surface. 

 Earlier studies showed that bruises can allow this penetra- 

 tion even though the skin is not broken. The study 

 reported here was conducted to see how blue mold rotting 

 related to impact bruising on apples. The authors con- 

 ducted a series of laboratory tests using Mcintosh, Deli- 

 cious, and Golden Delicious apples that were bruised on 

 surfaces contaminated with blue mold spores. 



Fruit were carefully picked and handled so as to 

 minimize pre-storage injury, stored at 34°F for 0, 2, or 4 

 months, and warmed to room temperature before bruis- 

 ing. They were bruised by being dropped onto a steel plate 

 from different heights, which caused impact bruising of 

 different severities. The surface of the steel plate was 

 covered with blue mold spores to inoculate fruit as they 

 impacted on it. Following bruising, the apples were kept in 



