Conditioning of pears so they’re ready to eat when purchased can boost retail sales, but there’s a lack of consistency in how it’s being done, according to the Pear Bureau Northwest.

D’Anjou pears are unripe when harvested and need to be held in cold storage for a time in order to ripen properly when purchased. After chilling, they ripen more consistently to a juicy, buttery texture.

Most d’Anjou pears are shipped straight from cold storage, but an increasing volume is being conditioned at the packing house so the pears begin to ripen and are ready to eat on the retail shelf.

The Pear Bureau has drawn up guidelines for conditioning, which involve warming up packed fruit to room temperature (68 to 70F), treating it with ethylene at 100 parts per million for 24 to 72 hours (depending on the time of year), and cooling the fruit afterwards to 32F. To be treated successfully with ethylene, the fruit must be in a container without a polyliner.

Some packers have invested in sophisticated facilities to condition their fruit. At other packing houses, fruit is packed in standard boxes with polyliners, warmed up in a storage room, and may or may not be treated with ethylene, said Dr. Gene Kupferman, postharvest Extension specialist with Washington State University.

Optimal methods

Kupferman is beginning a research project to find the optimal pear conditioning methods at various times during the season.

He noted that a conditioned pear is distinct from a ripened pear, which has a pressure of between 2 and 5 pounds and is ready to eat off the shelf. Ripe pears don’t travel well, so few shippers sell them.

Conditioned pears are partially ripened, but there’s no consistency among packers about what the target firmness of those pears should be, Kupferman said. "Everybody has their own idea of what a conditioned pear is."

He planned to work this fall with three packers using different conditioning methods to do two trials. In one trial, the packer’s own fruit will be used to study how it ripens after conditioning. He’ll also supply fruit to the three different packing houses to see how the results compare from the different conditioning methods when they use the same fruit packed in the same type of box without a liner.

In the second trial, he hopes to establish whether ethylene is essential for the fruit to be conditioned successfully. Once d’Anjou pears have received their chilling requirement after 30 to 40 days in cold storage, it’s possible that ethylene is no longer necessary for them to become soft and juicy, he said.

For this experiment, he will compare the conditioning of three types of pears: fruit that has not received its chilling requirement; fruit that has been in regular storage long enough to receive its chilling requirement; and fruit that has been held in CA (controlled-atmosphere) storage.

New Zealand researcher Dr. Keith Sharrock has developed a conditioning method using ethylene release capsules that can be used to treat covered pallets of packed pears, without the need for dedicated conditioning rooms. However, this won’t be part of his study, Kupferman said.

Taste tests

Kupferman will be collaborating with Oregon State University’s Food Innovations Center, who will have consumers taste fruit from the various treatments. Kevin Moffitt, president of the Pear Bureau Northwest, said the Pear Bureau’s current guidelines are based on purely scientific studies that did not involve taste tests. There’s been nothing to show what effect short cuts, such as not using ethylene, have on the quality of fruit in terms of aromas, sugar level, or juiciness.

"This will take it a step further," he said. "We’re going to start provingor disprovingthat ripening with ethylene in the way we have outlined will indeed give a better-tasting piece of fruit. We truly believe that ethylene will give the fruit some flavor aspects that you won’t get if you’re just heating it up."

Moffitt estimates that 35 to 40 percent of USA Pears sold on the domestic market are conditioned in some way. Some shippers don’t supply conditioned fruit because they’re concerned about the cost of having a dedicated ripening room or ripening trailers, or they are nervous about conditioning fruit and shipping it cross the country for five days, Moffitt said.

And some receivers don’t like the fruit to arrive at less than 10 pounds pressure. The Pear Bureau’s ripening consultant Dennis Kihlstadius has been working with quality-control people at the receiving end to assure them that a pressure of 9 to 10 pounds is not a reason to reject a load.


There’s been confusion at the retail level about what constitutes a conditioned pear because of the inconsistencies between various suppliers, Moffitt said, which has led to some buyers no longer asking for conditioned fruit.

A few retailers, including some divisions of Wal-Mart, are ripening their own pears, which Moffitt said is an ideal situation because they have much more control over the fruit quality when they do it themselves. Pears can be conditioned in the same room as bananas, because the temperature and ethylene levels required are the same for both fruits.

However, Moffitt believes that within a decade 80 percent of the d’Anjou pears on the retail shelves will be conditioned. Retailers have reported 40 percent increases in sales when the pears are sold ready to eat, and he thinks riper fruit on the retail shelf has played a role in the industry’s success in recent years by improving consumer satisfaction.

"If you don’t have the consumer satisfaction level, they’re certainly not going to pay the prices they are having to pay at retail today," he said. "Retail prices have gone up, and consumers are still buying. We just sold the third largest crop ever at good prices."