Strawberries: Quality Control & Testing
In the fresh produce industry, strawberries hold a place of pride among fresh fruits and vegetables due to their popularity and versatile usage. They’re also extremely popular fruit among consumers, enjoyed by over 94% of American homes.
But for producers, ensuring high-quality strawberries free of damage from disease and foreign matter is no easy task, given their sensitivity to handling and environmental conditions. Adopting effective fresh produce quality control practices is crucial in delivering strawberries that are free from damage and meet the highest quality parameters.
A strawberry’s flavor, texture, and aroma reach their peak 2-3 days after being picked. This is crucial for import and export businesses to consider, especially when shipping strawberries over long distances.
Common Defects when Growing & Harvesting Strawberries
Strawberries can be impacted by a number of defects and diseases throughout the supply chain.
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Pest Damage
Strawberries face threats from various pests, including aphids, tarnished plant bugs (TPBs), and spider mites. Aphids sap the vitality of plants while transmitting harmful viruses. TPBs feed on developing fruit, leading to deformities like cat-facing. Meanwhile, spider mites attack the underside of leaves, causing stippling, yellowing, and sometimes plant death. -
Red Stele
Caused by the pathogen Phytophthora fragariae, this disease induces root rot in strawberries, resulting in wilted, dead plants. This soil-borne disease severely impacts yield, often leaving entire crops unsalvageable, posing a significant challenge for strawberry producers worldwide. -
Botrytis Fruit Rot (Gray Mold)
Botrytis Fruit Rot, or Gray Mold, is a pervasive fungal disease affecting strawberries, causing soft, water-soaked, light brown to tan lesions on the fruit. This disease diminishes the aesthetic and edible quality of strawberries, leading to significant yield loss for producers. -
Leaf Spot
Leaf Spot, resulting from the Mycosphaerella fragariae fungus, creates small, round, reddish-brown spots on strawberry leaves, diminishing plant vigor and yield. This disease primarily affects the foliage, compromising the plant's ability to photosynthesize effectively and produce healthy fruit. -
Viruses
Strawberries are susceptible to various viral diseases like Strawberry Mottle Virus, Strawberry Mild Yellow Edge Virus, and Strawberry Crinkle Virus, which lead to symptoms like yellowing, leaf distortion, and stunted growth, significantly impacting fruit yield and plant health. -
Shape Defects
Strawberry shape defects often include 'nubbins', which are small, seedless areas resulting from poor pollination, leading to unexpanded flesh. Another common defect is 'double or multiple fruiting', where strawberries develop as conjoined fruits due to genetic factors, environmental conditions, or damage to flower ovaries during the early developmental stages. -
Physiological Disorders
Some defects are the result of physiological disorders rather than infections. Blossom Blight is one such condition, where blossoms turn brown and die, often due to environmental factors. Sunscald can also impact strawberries exposed to direct sunlight, causing them to develop bleached, white patches. Frost injury is another environmental concern where late frosts can damage new growth and flowers, subsequently impacting yields.
Interesting Facts About Strawberries
- Despite their name, strawberries are not technically berries. True berries, like bananas and grapes, have seeds inside. The small seed-like structures on the surface of strawberries are actually the fruits, and each one is called a "drupelet." An average strawberry has around 200 of them.
- Strawberries aren’t just tasty, they’re super nutritious, too: just eight strawberries contain more vitamin C than a medium-sized orange.
- There are around 103 species of strawberry. But the garden strawberry that we commonly eat today was first bred in Brittany, France, in the late 18th century. It's a hybrid of two wild strawberry species from North America and Chile.
- Short Harvesting Window: Strawberries have a very short harvesting window. Once picked, they won't ripen further. This is why it's important to pick them when they're fully red.
- During the quality assurance process, strawberries are often sorted by color. Fully red strawberries are generally considered premium grade. Lighter or green-tipped strawberries might be used for making jams or sold at a lower price.
Common Quality Parameters for Strawberries
- Color
- Diameter
- Degrees Brix (°Brix)
- Acidity
- Firmness
- Bloom
- Shape
- Calyx Condition
The Clarifresh platform also integrates with 3rd-party technology to evaluate external tomato attributes. Learn more here.
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