Catalytic Generators Describes Best Practices For Ripening Papayas

Papayas can be found year-round at your local grocer, thanks to strategic ethylene application.  Ethylene generators from Catalytic Generators will help to turn dark green papayas to a golden yellow color when ripened. To perfect the papaya ripening process by ethylene application, ripeners should follow the suggested protocols listed below:

Determine the fruit maturity when received.  The degree of maturity in papayas is related to external color development and will indicate whether the papaya should be exposed to ethylene. Papayas that are fully mature at harvest should not be ripened with ethylene if they are to be stored for an extended period. Papayas of ¼ to ½ yellow color minimum will benefit from a treatment of ethylene with an improvement in texture and color. Papayas that are immature (green) can ripen but will never develop good flavor. Other physical changes that are associated with papaya ripening include a decrease in flesh firmness, increased juiciness, and increased aroma volatiles.

Strategically place papayas within ripening rooms. If not using pressurized ripening rooms, then air stack the boxes (at least 2″ between boxes) to ensure proper air circulation. Leave 1½ feet between walls and pallets and about 6″ between pallets.

Utilize temperature and humidity management. Fruit temperature is the most important factor in papaya ripening.Ripening occurs faster when papayas have been previously held at low temperatures. Depending upon desired shipping time, bring the pulp temperature to the range of 72 to 82°F (22 to 27.5°C) for the best color development. The temperature within the room during ethylene application should be between 20 to 25°C (68 to 77°F); if the temperature goes above 86°F (30°C), ripening will be stalled.

Once ripened, papayas can be kept at 50 to 55°F (10 to 13°C) and 90 to 95% relative humidity for up to 1 week. The optimal relative humidity range to prevent excessive water loss and shrivel is at least 90% relative humidity.

Apply ethylene and vent ripening rooms. Apply 100 ppm ethylene for 24-48 hours (actual time of exposure to ethylene is determined by the maturity of the fruit; a yellowing of fruit color indicates that the papayas are producing ethylene and the generator is no longer needed) to induce faster and more uniform ripening, provided that carbon dioxide is kept below 1% by ventilating the rooms with outside air once per day. Rooms should be vented by opening doors or controlled fan exhaust ventilation for 20 minutes every 12 hours to flush out carbon dioxide and bring in oxygen.

To achieve 100 ppm, the generator setting[1] will depend on the size of the ripening room:

  • Setting 1 for rooms 1600 – 2500 cubic feet (45-70 m3 )
  • Setting 2 for rooms 2500 – 5000 cubic feet (70-142 m3)
  • Setting 3 for rooms 5000 – 7500 cubic feet (142-212 m3)
  • Setting 4 for rooms 7500 – 10000+ cubic feet (212-283+ m3)

Following these best practices will result in better papaya color, texture, and overall quality. Papayas have been ripened successfully for some time by using Catalytic Generators and Ethy-Gen® II Ripening Concentrate to produce ethylene in the ripening room. For more information regarding ethylene application, contact Catalytic Generators here.

[1] Please note that all rooms vary in terms of how air-tight they are, so if more precise PPM determination is required, air testing for ethylene PPM levels is recommended.


Brecht, Jeff. “Ripening Mangos & Papayas.” UC Davis Postharvest Technology Center, UC Davis Postharvest Technology Center, 19 Apr. 2017, (Accessed May 28, 2020).

University of California. “Fruit English.” Fruit English – UC Postharvest Technology Center, 2014, (Accessed May 28, 2020).

Best Practices for Washing Fruit & Vegetables During COVID-19

Protect your well-being by following these

best practices for washing fruit and vegetables.

It is common knowledge that fresh produce should be cleaned before eating to prevent illness caused by contamination; however, many do not know the best practices for washing their fruit or vegetables.

According to Glenda Lewis, an expert on foodborne illness with the Food and Drug Administration:
“Fresh produce can become contaminated in many ways. During the growing phase, produce may be contaminated by animals, harmful substances in the soil or water, and poor hygiene among workers. After produce is harvested, it passes through many hands, increasing the contamination risk. Contamination can even occur after the produce has been purchased, during food preparation, or through inadequate storage.”

The best solution to clean your fresh produce is amazingly simple: water. That is right, only plain water! All produce should be washed under running water while gently rubbing with clean hands. A clean vegetable brush can be used to scrub firm produce such as melons or cucumbers. For produce with leaves or outer layers, such as cabbage or lettuce, the outermost leaves should be removed. After rinsing, the fresh produce should then be dried with a clean cloth or paper towel to further reduce bacteria that may be present.

The FDA states, “Nearly 8 million people are sickened by food contaminated with harmful germs each year.” During this global pandemic, Catalytic Generators wants to ensure the public is aware of these practices to lessen the spread of germs and illness.


U.S Food & Drug Administration, Office of the. “7 Tips for Cleaning Fruits, Vegetables.” U.S. Food and Drug Administration, FDA, 10 June 2018,

COVID-19 Update From Our Company

At Catalytic Generators, we’re committed to providing fresh produce industry professionals with the resources to effectively ripen and supply fresh produce to consumers worldwide. In an effort to be transparent with you, our company shares the following information:

Our office is currently open. Ethylene application is essential to the ripening of fresh produce. From this, our office and manufacturing facility is considered essential to the agricultural infrastructure during this crisis.

Technical support is still available by phone and email. Domestic and international flights are limited in the upcoming weeks; we’d like to reassure our customers that our technical support team is available via phone and email.

Stay engaged with our social platforms. For the latest updates regarding our business in relation to COVID-19, be sure to follow us across social media platforms. Our team will put out live updates to ensure customers have our most recent response to this outbreak.

Pear Conditioning for Profits

According to Kevin Moffitt, President & CEO of Pear Bureau Northwest, “The Pear Bureau tracks real-world success in retailers that have undertaken a conditioned pear program in recent years; the results in many of the stores nearly doubled the numbers seen during the test.”

In 2012, the Pear Bureau Northwest commissioned a test through Nielson/Perishables group which showed that stores carrying conditioned pears increased their sales 19.5% more than the control stores who were not carrying conditioned pears. Sales continued to increase after the 12-week test in the stores carrying the conditioned pears.

Conditioned pears are described by Pear Bureau Northwest as pears that have been brought to the “just starting to ripen” state. Conditioning refers to the application of ethylene, a natural plant hormone produced by fruit as it ripens. To begin this process for pears, the commodity is placed in a ripening room, warmed to room temperature, and treated with ethylene. Once the desired firmness is reached, the temperature is rapidly brought down to 32°F. Other factors that must be managed include the time of ethylene application, pulp temperature, humidity, and CO2 levels.

Pear conditioning began in the mid 1990’s as shippers recognized the success of preconditioned banana and plantain sales. The Pear Bureau published the first pear manual with step by step instructions for pear conditioning in the late 1990’s and contracted with ripening consultant Dennis Kihlstadius in the summer of 2001. “We have been promoting it to shippers and retailers ever since; there are currently 49 retailers in the US and Canada who carry conditioned pears,” Moffitt explained.

“Gone are the days where shoppers picked up a pear at the local grocery store and found the fruit as hard as a rock,” stated Greg Akins, President & CEO of Catalytic Generators. “Nowadays, customers expect uniformly ripe, ready to eat pears, and that’s what our ethylene generators help to provide.”

Catalytic Generators’ ethylene generators and Ethy-Gen® II Ripening Concentrate form a system that, when used as directed, produces concentrations ideal for conditioning a variety of pears. The Easy-Ripe® generator features an adjustable ethylene output which allows for adaption to any ethylene PPM requirement or room size. With the specially formulated liquid Ethy-Gen® II, the Easy-Ripe® easily makes only as much ethylene as needed for a target room, eliminating the need to store large quantities of compressed gas on site. Ethylene producing generators of Catalytic Generators all feature user-friendly operation and continuous, consistent ethylene production for superior ripening and degreening. These ethylene generators provide a safe, easy, and convenient ethylene source that you can trust.

Pear Bureau Northwest estimates that nearly 30% of the conventional green Anjou pears on retail shelves in the United States and Canada have been conditioned with ethylene. However, only about 3% of the conventional red Anjou and 2% of the conventional Bartlett crop are being ethylene conditioned.

Moffitt stated, “We see a lot of upside for conditioned pears, especially red and green Anjous. We have been telling retailers that a ripe Anjou is the new pear variety!”