01/21/2008
The benefits of using carbon dioxide to displace oxygen and ethylene in a pallet of strawberries during shipment has long been known, and the technique of enclosing the pallet in a bag and flushing out the oxygen and ethylene by using carbon dioxide has been widely used in the strawberry industry for some 25 years.

About five or six years ago, a new carbon dioxide delivery system, developed by a company appropriately named CO2 Technologies, was first applied to strawberries, according to Danny Brigham, a partner in CO2 West in Santa Maria, CA, which specializes in providing a CO2 Technologies system known as CO2 Activ-Pad to the strawberry industry.

Recently, California Polytechnic State University in San Luis Obispo conducted studies demonstrating the efficacy of the CO2 Activ-Pad technology for strawberries in comparison to the "more traditional Tectrol method." According to a written statement from CO2 West, "The four areas of comparison that were measured by the scientists were decay, firmness, color and temperature. The results showed that no significant differences could be found between the CO2 Activ-Pad treated berries and berries treated using the more traditional system.

The Cal Poly study was undertaken in response to requests from CO2 West customers who asked for "some third-party audits," Mr. Brigham said.

The patented CO2 Activ-Pad concept involves the use of a carbon dioxide- generating pad that is placed on top of the pallet of berries, which is then covered with a standard 3.5-mil plastic pallet bag, Mr. Brigham explained.

Unlike the more traditional method, which requires the bag to be sealed to prevent the carbon dioxide from escaping, the Activ-Pad technique leaves the bag open at the bottom, as the pad releases a steady amount of moist carbon dioxide vapor for up to 10 days during transit. Being heavier than the other gases, the carbon dioxide flows down through the pallet, keeping oxygen and ethylene away from the berries.

Eliminating the oxygen prevents the growth of botrytis mold and bacteria on the berries. Eliminating the ethylene, the natural ripening agent generated by the berries themselves, prevents the berries from ripening too quickly during transit.

"The CO2 Activ-Pad system now makes shipping strawberries much less complicated, more cost efficient and minimizes risk," according to the company's statement. "Customers now have the ability to inspect the pallets without losing the treatment or having to re-treat the berries at distribution points."

There is also no concern about the effectiveness of the carbon dioxide treatment being compromised by a torn or improperly sealed bag, added Mr. Bingham. In addition, cooling is more effective because the bag is left open, he said. Earlier comparative tests involving side-by-side shipments of product to a customer in the Midwest had shown slightly cooler pulp temperatures with the CO2 Activ-Pad system as well as reduced shrink and a brighter berry appearance.

Mr. Brigham told The Produce News that he first became involved with the technology when Wes Doldt, president and founder of CO2 West's parent company, CO2 Technologies in Urbandale, IA, approached him and his partners at Santa Maria Produce, a shipper and broker of strawberries and other produce items.

"They wanted a little bit more exposure on the product," he said. "I've spent 20-plus years in this business, from the cooler end [to] the sales department, and he thought with the contacts that [we] had, we could help get this product out there."

After doing some trials sending strawberries from California to Florida, "we got into basically an exclusive distributorship for a certain territory," he said. Then about two-and-a-half years ago, "Greg Sabosky and I, along with Mark Wortham, bought the technological rights for the strawberry business" and became partners in CO2 West.

The technology has undergone several iterations. "We have done some research and development" to improve the rate, consistency and duration of the carbon dioxide release to get the best results for strawberries, he said. "We are growing," Mr. Brigham added. "We have picked up four or five new customers" during the past year, "and we are working on other ones."