WSU Tree Fruit Research & Extension Center

Tree Fruit Market Diseases

Thursday, November 23, 2017

WSU-TFREC/Postharvest Information Network/Tree Fruit Market Diseases/pearfreeze



Before improvement in temperature control and air circulation in refrigerated warehouses, there was at times considerable loss from freezing injury of pears. With modern methods of refrigeration and handling practices, freezing injury appears to be practically eliminated. The following statement is therefore retained only as a matter of record.

When pears of the Bartlett and Anjou varieties are exposed for long periods to temperatures only slightly below freezing, they develop a condition that is fairly definite in its symptoms. In all cases the affected specimens have a glassy, water-soaked external appearance (top photo). When such fruits are cut, the water-soaked condition is seen to be confined to certain parts of the flesh (bottom photo). Usually it involves several layers of cells just beneath the skin. It may occur also within the core area. The remaining flesh is usually dry and pithy; and in cases of severe injury it may be badly cracked, so that there are numerous open spaces. Freezing injury should not be confused with old-age breakdown.

Pears showing the symptoms just described often remain in an unchanged state for several weeks. They seem to be rather resistant to decay and do not undergo normal breakdown from overmaturity, but they are inedible and have no commercial value.

The injury has been found to develop slightly in 4 weeks and to become severe in 6 weeks in pears held at a temperature of 27 °F, which is slightly below their average freezing point (28 °F).

Pear injury from prolonged freezing in storage
Pear injury from prolonged freezing in storage

Pear injury from prolonged freezing in storage
Pear injury from prolonged freezing in storage

Pear freezing injury
Pear freezing injury

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