Work is currently being conducted on overwraps that accumulate carbon dioxide in the pack, but even this new technology is not very effective without good temperature management. Prompt cooling, and maintenance of proper temperatures and humidity, are essential. The cooling process should occur in two stages. Simply setting harvested berries in a cold room is not adequate because the field heat is not removed fast enough. Rapid movement of cold, humid air through the berries is essential during the first few hours after harvest.
Brokers contend that for every hour delay in cooling, shelf life is reduced by one day.
Growers can take advantage of night cooling by harvesting fruit as early in the morning as possible. Large growers may have a separate pre-cooling facility specifically designed for removing the field heat, but inexpensive, effective improvisations can be adapted for any cold storage. If a grower only has a walk-in cooler, recently picked flats of berries can be set into a cardboard box which is opened at both ends. A household fan is then placed at one end of the box to draw air through the flats. Once the berries are cool, flats are removed from the cardboard and wrapped in plastic.