University of California and MCI issue guide for air exchange

Sound settings: The best advice from post-harvest biologists at the University of California is now available in an easy-to-use guide for air exchange technologies like AV+.

The guide is the result of cooperation between reefer producer MCI and University of California, aimed at achieving energy savings and delivery of fruit and produce in optimal conditions.

Helping fruit and vegetables breathe: Using a CO2 sensor, AV+ allows the produce to dictate the level of fresh air exchange based on its respiration rather than an often ambiguous fixed-vent opening that is based on the presumption of a constant fan speed. However, fixed vent openings leave many variables that can alter the actual air volume being exchanged.

The key is to provide the best possible conditions for fruit or vegetables in the cargo container from point A to B, says Malcolm Dodd, principal consultant, Cold Chain Solutions.

“The longest period of time during the post-harvest life of produce is usually spent inside a reefer container. The fruit, flowers, or vegetables are still consuming oxygen and give off carbon dioxide. Open air exchange vents, known as AirEx, are not precisely engineered, and there is much variability in the amount of air that moves through the vents. There are also varied opinions around the globe regarding what is the best AirEx for different types of fresh produce. It makes sense to manage the air exchange with an engineering solution. The AirEx vent can be mechanized and the opening controlled according to the respiration rate of the product being carried. The result will be better quality produce after the shipping voyage,” Dodd says.