Cherries do not contain stored carbohydrates like apples and pears, therefore have a shorter storage and shelf life, but good fruit quality can be maintained in cold storage for a couple of months. Cherries are difficult to handle because they are very susceptible to bruising (pitting), and extra care is taken on the packing line to eliminate mechanical injuries. Packers refer to a “cold-chain,” which signifies keeping cherries cool during the whole process chain (harvest through the packing process, shipping, retail markets, and until they are consumed.) To start the cherry packing process, cherries float onto the packing line on flumes of water, which protect them from bruising and damage. Orchard debris and leaves are removed from the flumes with nets. The cherries go through a cluster cutter to cut stems of clusters into single fruit with shorter stems. Fruit is sorted and sized, either manually by trained personnel, or electronically, with a computer. With the computer sorter, multiple images of each cherry are taken, analyzed, and fruit are automatically sorted and sized. Fruit that were singled out are sorted again by hand for culls. Some operations hydro-cool fruit before packing to maintain fruit quality. Cherries are packed into a variety of boxes, clamshells, and bags by size and weight. Cartons are then labeled, palletized, shrink-wrapped and sent to cold storage or refrigerated trucks for shipping.
Each of the steps taken at the cherry packinghouse are as follows:
Cherry bins are brought in to the facility with a forklift.
1. The bins are lifted up into the bin dump, where the cherries are dumped into sanitized water (to decrease the impact of the drop on the fruit).
When the cherries are dumped into the water, those that float are removed, and the rest continue on a conveyor belt to continue along the cherry packing line.
When cherries grow and are harvested, they are harvested as clusters and not as individual cherries with an individual stem. As a result, there is a section of the packing line where there are cutters that are meant specifically to cut the bunches so that the cherries come out as individual cherries (not being connected to another cherry via the stem).
2. The cherries are hand sorted for defects, including decay and splits. Throughout this process, the same fruit continues down the conveyor belt passing multiple sorters. There are brushes along the line to rotate the fruit so that if there was a blemish on one side of the fruit that was missed by one worker, after the fruit is rotated, another worker will catch it. There are two options for getting rid of the fruit in this case: culls (garbage or animal feed) or redistributed to a secondary market (e.g., double cherries for produce markets).
The cherries go into the hydrocooler to remove any residual field heat, so that all cherries come out at the same temperature (~32-34°F) when they go to the cooler. This step is where the sanitizer is added to the water. (Depending on the commodity and the packinghouse, the water used in the wash step can either be recycled or used as single use.)
3. The fruit goes through an optical sorter to be sorted by size and for any defects that were missed previously. This sorter designates the fruit to certain packing lines so that the fruit can be packed together with the other fruit that is the same size. (This is done to meet customer specifications and also to ensure that the packer is receiving proper compensation.)
Once the allocated amount fills the scales, the fruit drops into the bags. The bags are then packed into boxes and once the boxes are filled, they are sent onto another conveyor belt. Within the boxes, there is an additional bag surrounding the bags of packed cherries. This bag acts as modified atmosphere packaging (MAP), and is used to extend the shelf-life of the cherries.
4. There is a final weigh and quality step to make sure the boxes meet customer specifications. If they do not weigh enough, additional fruit will be added.
The boxes are packed onto pallets.