Friction bruises occur as brown to dark brown, irregular surface areas affecting the skin and the tissues immediately beneath it (top photo). The injury results when the skin is abraded by the rubbing of one fruit against another or against hard surfaces encountered in grading and packing operations. Abrasions or skin discolorations can also occur in transit from vibrations that cause movement of jumble-packed pears in cartons or loosely-held pears in trays. Sometimes such injuries show up as continuous bands around the fruits (bottom photo).
Pears packed immediately after picking are fairly resistant to abrasion. As pears age in storage, they become progressively more susceptible to friction injuries. Bartlett and Anjou pears are more susceptible than the russeted varieties such as Winter Nelis and Bosc. Anjou pears should be held no longer than 1 month and Bartletts no longer than 2 to 3 weeks in recommended 30° to 31 °F storage before packing.
Fruits packed in wooden boxes are protected from wall abrasions by the use of heavy paper liners. The bulge of the wooden box adequately prevents pear movement in transit. The use of paper pads over pears under slight compression will protect fruits in cartons against friction or roller bruising in transit.
Pear friction bruise (rubbed spot)
Pear friction bruise (rolling injury)