Commodities / Blueberries

Flavor | Texture | Color | Size | Defects and Disease | Shelf Life | Nutritive Value
MW Commercial Small Fruit and Grape Spray Guide | MW Small Fruit Pest Management Handbook | Postharvest Information (UC Davis) | USDA Grade Standards

Blueberry quality is a combination of appearance and flavor. According to grade standards, U.S. No.1 consists of blueberries which meet the following requirements: (1) Similar varietal characteristics; 2) Clean; (3) Well colored; 4) Not overripe; (5) Not crushed, split, or leaking; and, 6) Not wet.
Fruit should be free from: (1) Attached stems (2) Mold (3) Decay; (4) Insects or when there is visible evidence of the presence of insects; (5) Mummified berries; and, (6) Clusters, and free from damage caused by (1) Shriveling; (2) Broken skins; 3) Scars; and (4) Green berries.
Quality characteristics of interest to the grower include plant vigor, yield potential, and disease resistance.

Flavor top

Blueberry flavor is related to degree of ripeness. Fruit that is harvested at full ripeness will have the highest sugar content and flavor. Fruit that is not fully ripe will have low sugars, higher acid, and lack flavor.

Texture top

Blueberry fruit should be firm. Excessively ripe fruit can be too soft.

Color top

Blueberry varieties vary in color from light blue to purple to nearly black. Most varieties have a waxy "bloom" on the fruit that makes it appear lighter in color. For a given variety, fruit should be fully colored, without red or green areas on the back of the berry near the stem scar.

Blueberries are bright colored at harvest. Water loss will cause the fruit to become wilted and dull. Excessive handling can cause the waxy bloom to be wiped off, giving the fruit a dark, dull appearance.

Size top

Blueberry fruit range is size by variety and as the season progresses. Many new varieties produce very large fruit that are over 3/4 inch in diameter. Large size is often more favored for fresh consumption, but not for processing uses. There are size standards for blueberries based on the number of berries that will fill a cup measure. Extra large fruit takes less than 90 berries per cup; Large, 90 to 129 berries per cup; Medium, 130 to 189 berries per cup; and, Small, 190 to 250 berries per cup.

Defects and Disease top

Defects

Soft fruit, wet stem scars, attached stems, and green berries are common defects of blueberries. These must be graded out during packing.

Disease

The most common diseases affecting blueberry fruit are anthracnose and Alternaria. Control recommendations can be found in the Midwest Small Fruit Pest Management Handbook and Midwest Small Fruit and Grape Spray Guide for Commercial Growers, or through your local Cooperative Extension Service.

Gray Mold (Botrytis cinerea) and Penicillium fruit rots can occur in storage.

Insects

European Japanese beetle, blueberry maggot, and cherry/cranberry fruit worms are the most common pest that affects fruit quality. There are grade standards that cover allowable insect damage. Tolerances vary depending on the pest.

Shelf Life top

Decreased quality during postharvest handling is most often associated with water loss and decay. Blueberries have a longer shelf life than most other berry crops and can be stored for as much as 6 weeks. Storage for up to 2 weeks is most common. Some use of controlled atmosphere storage has been attempted, but off-flavors can develop.

It is important to remove field heat as soon as possible to prevent water loss and retard decay. Most shippers will use forced air cooling to achieve temperatures of 31-32˚F. Maximum shelf life of can be expected if these temperatures are maintained at 90% to 95% humidity.

Nutritive Value top

Serving Size: 1 cup blueberries (140g)
Amount Per Serving

% Daily Value*

Calories 100 Calories from Fat 10
Total Fat 1g 1%
___Saturated Fat 0g 0%
___Cholesterol 0mg 0%
Sodium 0mg 0%
Total Carbohydrate 27g 9%
___Dietary Fiber 3g 14%
___Sugars 11g  
Protein 1g  
Vitamin A 0%
Vitamin C 15%
Calcium 0%
Iron 2%
*Percent Daily Values are based on a 2,000 calorie diet.
(Source: Produce Marketing Association and the Produce for Better Health Foundation. 2002-2003.)
Blueberries, Raw 1 cup
Weight of Household Measure % Water Food Energy
K cal
 Protein Fat Saturated Fatty Acid Mono - unsaturated Fatty Acid Poly - unsaturated Fatty Acid
145g 85 80 1g  1g 0g 0.1g 0.3g
Cholesterol Carbohydrate Calcium Phosphorus Iron Potassium Sodium Vitamin A (IU)
 0mg 20g 9mg 15mg 0.2mg 129mg 9mg 150
Vitamin A (RE) Thiamin Riboflavin Niacin Ascorbic Acid      
15 0.07mg 0.07mg 0.5mg 19mg
(Source: USDA. Nutritive Value of Foods (HG-72), Release 3.2. 1990.)


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Content author: B. Bordelon, 2003. Links updated:January 2011.