[Global Star K-Food]③ Freshness UP with New Technology... Accelerating Overseas Export of K-Nongsanmul

RDA Develops CA Container
Controls Oxygen and Carbon Dioxide to Enhance Freshness
Reduces Shipping Costs Using Affordable Vessels
Extends Strawberry Shelf Life to 15 Days with Specialized Functional Container

Strawberries, a major export item of our country, are mainly exported by air. This is because their easily perishable nature requires minimizing transportation time. However, exports via ships, which have lower logistics costs, are expected to increase in the future. By using CA containers and functional packaging that suppress spoilage caused by the respiration of agricultural products, the shelf life of fresh strawberries can be extended, and distribution costs can be significantly reduced.

CA container under demonstration research by the Rural Development Administration.

On the 22nd of last month, at the Postharvest Management Research Building of the National Institute of Horticultural and Herbal Science under the Rural Development Administration located in Jeonju, a demonstration of CA containers was underway. Using four CA containers of different sizes, agricultural products were stored, and demonstrations were conducted on temperature, humidity, oxygen, and carbon dioxide concentrations for each product. After finding the optimal technical conditions, these are applied to actual export items.

The CA container is a container that the Rural Development Administration began researching in 2021, which allows maintaining freshness by controlling the atmospheric environment even during the transportation of agricultural products. After harvest, agricultural products respire like humans by absorbing oxygen and releasing carbon dioxide. When carbon dioxide levels rise, spoilage accelerates, so controlling this concentration helps maintain freshness longer. Overseas, CA containers are used to export perishable agricultural products such as avocados, bananas, asparagus, and blueberries.

Ji-hyun Lee, an agricultural researcher at the Rural Development Administration, explained, "General containers only control temperature and humidity, but CA containers can also control oxygen and carbon dioxide levels. By controlling these, the aging of agricultural products?that is, the softening or beginning of decay?can be delayed, making it currently the most advanced distribution method."

A device installed behind the CA container that controls temperature, humidity, oxygen, and carbon dioxide.

The core of the CA container is maintaining constant oxygen and carbon dioxide concentrations, but the optimal levels vary by product. To this end, the Rural Development Administration is conducting research through demonstrations to establish optimal standards by product and transportation period. Last year, they conducted demonstrations on strawberries, peaches, oriental melons, melons, and tomatoes exported to Hong Kong and Vietnam, and this year, including these, they are conducting studies targeting the U.S. (grapes, citrus) and Canada (citrus).

The advantage of CA containers is that transportation costs are cheaper compared to air freight. For air transport, a standard 40-foot general container costs about 20 million KRW, and a CA container about 30 million KRW, which is expensive. However, using CA containers that can maintain freshness longer allows agricultural products to be shipped by sea, which has lower logistics costs than airplanes. According to the Rural Development Administration, for 400 kg of strawberries (200 boxes of 2 kg each) shipped to Hong Kong, logistics costs are 3.35 million KRW for conventional containers (reefer), 6 million KRW for CA containers, and 20.2 million KRW for air freight. However, the product quality of reefer containers drops from 100% at departure to 70%, while CA containers maintain 93%, similar to air freight. The researcher said, "Overall, if reefer logistics cost is 1, CA containers are 2.5, and air freight is about 10. CA containers maintain product quality comparable to air freight but at about one-fourth the cost, making them competitive."

Functional packaging container developed by the Rural Development Administration (right) and the existing ginseng packaging container.

The Rural Development Administration is also achieving results in packaging methods that can maintain freshness longer. Representative examples are ginseng and strawberries. Generally, ginseng has been exported vacuum-packed with soil attached, resulting in a high loss rate of 8%. The Rural Development Administration developed a high-pressure washing method that minimizes damage to ginseng, surface drying, and breathable containers. Min-seon Jang, a researcher at the Rural Development Administration, said, "Through this, the loss rate during distribution was reduced to 1%, and freshness improved 2.5 times. Using breathable functional containers instead of vacuum packaging can extend the shelf life by 1 to 2 months."

They also developed a packaging technology dedicated to strawberries that can keep them fresh for up to 15 days after harvest. This functional container eliminates breathing holes but adds functional materials to the bottom and is designed in an egg-carton shape to suppress bruising caused by impact. Researcher Jang explained, "The container prevents moisture evaporation through holes and adds zeolite, a mineral that absorbs ethylene?which causes aging during respiration?to the bottom material. We confirmed that using functional containers and maintaining appropriate temperatures allows distribution for up to 15 days after harvest."

Functional container in a honeycomb shape developed by the Rural Development Administration.

To maximize the effect of functional containers, pre-packaging treatment processes are necessary. Strawberries undergo a pre-cooling process at Agricultural Product Distribution Centers (APCs) after harvest to lower temperature before distribution. The Rural Development Administration patented a 'simultaneous complex treatment' technology that hardens the flesh by carbon dioxide treatment and sterilizes by chlorine dioxide fumigation during pre-cooling, and supported 25 APCs nationwide.

An official from the Rural Development Administration stated, "CA containers and functional packaging will contribute to increasing the freshness and sales period of K-agricultural products and diversifying export destinations. Since freshness determines quality and price, we plan to continuously develop and advance packaging technologies tailored to each product’s characteristics and various technologies that suppress softening or decay, applying them to distribution and export sites."