Producing High Quality Wild Blueberry Fruit

E.2.0

The production of high quality wild blueberry fruit has always been important. Increases in highbush blueberry production is making the quality issue an increasingly important one in wild blueberries. In order to safeguard the high quality standards of the wild blueberry industry, every grower needs to adopt management practices that will favour the production and transport of quality berries to the processing plant. If poor quality berries enter the system, it leads to a decrease in overall quality and product grade, and increases in wasted fruit "shrinkage". No one is a winner in that situation.

The production of quality fruit is not limited to proper harvesting technique. A quality fruit begins with a proper fertility program and excellent pollination.

Many factors can affect the quality of wild blueberries. Some factors are controllable, while others are less so.

Raking:

Avoid overfilling the rake before emptying it. Do not wait until the fruit get stuck between the teeth and are squashed. The same rule applies to push harvesters. The fruit should not be poured into the box from too high. The longer and more numerous the falls, the more damaged the fruit will be.

Be sure that the rakers know proper raking technique.

Raking should be done at a steady rhythm, rather than at a frantic pace.

Field cleanliness:

Weed control is essential for producing quality berries, since the presence of these can really damage the berries during raking.

Clear the fields of debris that can get caught in the teeth of the rake and find its way to the boxes. This applies to all harvest techniques.

Winnowing:

The pouring of berries into the winnowing machine, as well as their fall from the chute will influence fruit quality.

The greater the fall, the worse will be the damage to the fruit. Therefore, empty the berries into the winnowing machine from the lowest height possible and place the box as close as possible to the end of the chute where the winnowed fruit are collected. This is especially important around the end of the harvest season when the fruit are less firm, and thus more prone to damage.

Note: Some processors prefer to receive berries that have not been winnowed, especially when the fruit travels a great distance. The leaves act like cushions and reduce the risk of the fruits squishing each other. Consult your buyer to know his/her requirements.

Containers:

Avoid darkly coloured containers. They absorb more heat.

Avoid tall harvest buckets. The pressure exerted on the fruit at the bottom of the bucket is too high, and this will increase the amount of damaged fruit. In these buckets, the air exchange is limited, thereby resulting in an increase in the fruit temperature.

Boxes should not be overfilled. Respect the limit borders on the boxes.

Holding time:

In the field, try to minimize the heat by putting the filled boxes in the shade. Cover the top box, since it receives the direct heat of the sun.

Boxes of wild blueberries should make their way to the receiving station or processing plant promptly.

Temperature:

Attempt to keep the fruit sheltered from direct sunlight, especially on warm days. An intense heat will increase the chemical deterioration of the berries and favour the development of diseases such as grey mould.

Weather conditions:

During periods of extremely hot weather, it may be preferable to harvest only in the morning. This will keep the berries firmer and less prone to damage. Do not harvest when the plants are wet. Wet conditions make the leaves and fruit stick to the rake. This makes the fruit lose its waxy covering ("the bloom"). It also results in more debris and more losses. Furthermore, wet conditions are quite uncomfortable for rakers.

Time of harvest:

If possible, harvest should be delayed until 90% or more of the fruit is ripe. Harvesting too early results in weight loss and generates too many white berries. The need for careful harvest techniques is even more pronounced with late harvests, when the berries are fully ripe, and therefore softer and more easily damaged.

References:
Yarborough, David. 1994. Methods for Producing and Harvesting High Quality Wild Blueberries.1994 N.B. Hort. Congress.

Harvesting for Blueberry Quality. 1994. Public Affairs Division, University of Maine.

Prepared by Gaétan Chiasson, P.Ag. Horticulturlal Specialist , and John Argall, P.Ag., Blueberry Specialist, N.B. Department of Agriculture & Rural Development.
Winter 1996