Skip to content.
Français

Some features of this website require Javascript to be enabled for best usability. Please enable Javascript to run.

Ministry of Agriculture, Food and Rural Affairs

Core Breakdown

Core breakdown is a natural senescent occurrence in pears and is greatly influenced by handling and storage procedures.

Identification

  • During ripening the fruit softens, loses chlorophyll in the skin and develops a characteristic flavour and a foul odour
  • Browning and watery collapse of cortex tissue
  • Confined to the core or may extend to surrounding flesh
  • Darkening of the main vascular elements between the stem and core
  • In the early stage, the affected tissues are soft and watery
  • In late stages, the colour becomes brown or black
  • Rapid breakdown and browning of the entire fruit may occur in severe cases

Biology
The time between ripening and the occurrence of breakdown is a critical period in the consumption and processing of the fruit. This interval, which may be a week or more in fruit ripened soon after harvest, decreases with late harvesting, adverse storage conditions, or an extended storage period. When such cultivars as Bartlett and Bosc, which ordinarily do not ripen at low temperatures, are kept too long in cold storage and then transferred to room temperature for several days, core breakdown may occur before the fruit has fully ripened. Continued cold storage leads to a complete loss of ripening capacity. Anjou, which is capable of ripening slowly at low temperature, may develop core breakdown while in cold storage.

The specific cause of core breakdown in pears is not known. The assumption is that pears harvested after optimum maturity are unable to slow their life processes enough for successful storage at -1°C. Abnormal metabolism follows and serious breakdown can occur in storage or after the pears are removed to ripen at 18 to 21°C.

Period of Activity
Core breakdown is classed as a market or storage disease of pears, but its time of occurrence depends largely upon the maturity of the fruit at the time of harvest. In freshly harvested pears, the time between the ripe stage and the occurrence of breakdown is approximately one week. The longer fruit are in storage, the shorter this time becomes. In fruit which are over-stored these changes occur so quickly that at no time is the pear fit to eat, and the breakdown may occur before the fruit becomes ripe.

Scouting Notes
Bartlett, Bosc and Clapp are most susceptible, whereas Anjou pears are somewhat resistant.

Monitor fruit color as it approaches the end of its typical storage life. Yellowing in storage is a good indication of susceptibility to core breakdown.

Threshold
Do not store pears beyond their post-harvest life.

Management Notes
Controlled atmosphere storage and SmartFreshSM technology are effective in extending the storage life of pears without increasing the tendency to core breakdown. The connection between mineral nutrition and core breakdown has not been established; however, high fruit calcium content may be correlated with reduced susceptibility.

Harvest fruit at optimum maturity (no less than 18-19 lb).

Cool fruit as soon and as rapidly as possible after harvest.

Avoid storing pears beyond their post-harvest life.

Store fruit at the lowest non-freezing temperature (generally -1 to 0°C). Do not store at below -1 C.

Some information included above is excerpted from:
http://postharvest.tfrec.wsu.edu/marketdiseases/pearcorebreak.html

Click to enlarge.