The blueberry chain
Steps in the blueberry chain
HarvestThe postharvest chain starts with the harvest of the blueberries. As the edible quality of blueberries does not improve after harvest, they should be picked at a near to full ripe stage. Careful picking at the right maturity is crucial for quality later in the chain. Transport to the packhouse should follow soon after harvest, to allow cooling down of the fruit as quickly as possible. A fast reducing of the product temperature brings important benefits to the shelf life of blue berries.
PackhouseIn general, it is advisable to do only the strictly necessary handling to reduce the risk of mechanical damage. However, packhouse activities consist of many essential and important steps, such as sorting/grading/packing. Failure to sort and discard immature, overripe, undersized, misshapen, blemished, or otherwise damaged fruit creates problems in subsequent chain links. Grading helps also to achieve a more uniform product appearance which is important for the classification of the product and hence for the pricing.
CA storage and MA packaging
Blueberries can be stored under Controlled Atmosphere (CA) in order to extend the market supply period for a period up to 10-12 weeks maximum. This requires the best combination of growing and harvesting climate, variety, maturity, postharvest infrastructure. The most optimal conditions varies with initial quality and local experience. A safe condition is 10 % CO2 and 11 % O2. Be aware of off flavor with CO2 levels higher than 12 %.
If CA storage is not suitable for a specific chain, a Modified Atmosphere (MA) packaging might be an alternative. This type of retail packaging will allow a higher CO2 level and a lower O2 level than in the normal air. Combined with a cold temperature, the MA packaging may offer similar performance as the CA storage. But watch out! The cold chain must be maintained at recommended temperature as the MA at higher temperature will develop suboptimal MA conditions with negative quality aspects.
Transport and distributionThe different production locations throughout the world make that the distribution chain of blueberries often requires long distance transportation. Only a small amount of the overseas blueberries is transport by air freight, and most berries are shipped with reefer containers sometimes under CA conditions. For shorter distances, for instance within Europe, blueberries are transported in refrigerated trucks. Regardless of the means of transportation, keeping the product temperature during transit below 2°C is very important, without breaking the cold chain. During transport, temperature monitoring takes place.
RetailBlueberries should look fresh, appealing, and free of overripe, damage or rotten berries. Fruit condition at the point of sale must be good enough to ultimately arrive at the consumer's home with at least acceptable quality. The quality of blueberries is strongly dependent on temperature. Therefore, keep them refrigerated and remove packages with overripe, damage or rotten berries. Moreover, include first-in, first-out inventory management unless quality indicates otherwise.