General

The primary objective of postharvest handling of blackberries and raspberries is to maintain fruit quality. Follow the general guidelines below for harvesting blackberries and raspberries:

• Pick in the morning while the temperature is still cool and the berries are firm.
• Avoid picking when raining.
• Pick and handle the fruit carefully to avoid crushing or bruising.
• Place harvested fruit directly into the picking container.
• Have a separate container for culled fruit. Fruit culled for cosmetic reasons may be frozen or used in processing.
• Gently place the berries no more than two to three berries deep in berry baskets or picking containers to avoid further bruising during storage. For this reason, half-pint containers are recommended.
• Cool the fruit as soon as possible after harvest. Coolers should be set at 33 to 35°F with 90% to 95% relative humidity. Use room cooling or forced air cooling.
• Approximately six to eight trained pickers are usually recommended per acre.
• A variety of picking containers are available from your local distributor. Each one has its advantages and disadvantages. Decide which type of basket suits your individual needs:
  • Pulp baskets are inexpensive, have ventilation holes for cooling, and can absorb water from fruit harvested wet; however, they absorb juice on the bottom, which may be undesirable.
  • Polystyrene baskets are lighter, absorb less water, and can be printed with a label.
  • Commercial growers most commonly use clamshells. Clamshells are sturdy, plastic, vented boxes with hinged lids that allow boxes to be stacked without crushing the fruit. An absorbent pad is placed in the bottom of each clamshell to absorb excess juice and moisture from the fruit.
• Use picking stands to prevent containers from contacting the ground.

Blackberry

Harvest blackberries at least twice a week. For pick-your-own and local sales, it is better to pick when the color has a dull appearance to maximize flavor. At this stage, berries will have higher sugars but reduced shelf life and are best suited for local markets. For shipping, pick blackberries when they are shiny black for acceptable flavor and longer shelf life (Figure 22).

Postharvest handling of blackberries is critical when selling fruit to retail or wholesale markets. Fruit reddening is a manifestation that can occur in stored blackberries. It is characterized by one or several bright red drupelets that detract from the attractiveness of the berries. Although the exact cause is not certain, possible causes include cultivar, early harvest date, temperatures above 77°F during picking, immature fruit, chemical composition, and condensation on the fruit.

Figure 22. Shiny black (right) and dull black (left) Ouachita fruit.

Penelope Perkins-Veazie, NC State University

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Figure 22. Shiny black (right) and dull black (left) Ouachita fruit.

Penelope Perkins-Veazie, NC State University

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Raspberry

Harvest raspberries daily. Raspberry fruit are very soft and even more perishable than blackberries. Recent studies have shown that fruit can be harvested at the pink or light-red stage for fresh market sale or at full redness for immediate sale at pick-your-own operations (Figure 23). Fruit that was picked unripe (yellow-pink) achieved full color, soluble solids content, acidity, and flavor (tasted at random) after six days of storage. Fruit picked pink was much firmer and less leaky than berries picked at the normal commercial fresh market ripe stage. However, they found that fruit picked at this stage was 4 to 20 percent smaller, depending on variety and relative ripeness at harvest. Growers will have to determine whether extended shelf life or fruit size is more important.

Figure 23. Ripe and unripe (UR) berries on the day of harvest (day 0) and eight days after harvest.

Penelope Perkins-Veazie, NC State University

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Figure 23. Ripe and unripe (UR) berries on the day of harvest (day 0) and eight days after harvest.

Penelope Perkins-Veazie, NC State University

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