A batch of blueberries arrives at the packing station, but some of the smaller berries keep slipping through the holes in the bottom of the trays. The larger ones stay where they should, so the problem is not immediately obvious. Workers may only notice it after several trays have been filled or packed into shipping cartons.
Changing to a tray with fewer openings might seem like an easy fix. However, fresh fruit still needs airflow, and removing too many perforations can create another problem. What matters is where the openings are placed, how wide they are, and whether the surrounding structure can support the smallest fruit in the batch.
For fruit packers, this is a packaging issue worth checking before committing to a large production order.
Why Do Small Fruits Slip Through Fresh Tray Openings?
Fruit size variation is one of the first things to investigate. A tray may work well with a sample selected from the middle of a size range but fail when smaller fruit enters the packing line.
Take blueberries as an example. Two batches may have similar average berry sizes, yet the proportion of smaller berries can differ considerably. If the tray was developed using only average measurements, those smaller berries may find their way through the bottom perforations.
The same issue can occur with small grapes and other round or oval produce. Their shape, not just their diameter, affects how they sit against an opening.
Movement makes matters worse. During filling, carton handling, and road transportation, fruit can roll away from its original position. A berry that was initially resting on a supporting rib may move over a perforation and fall through.
This is why custom fresh tray manufacturers need to understand the actual fruit size range and packing conditions before finalizing the mold design.
Are All Ventilation Openings Suitable for Small Fruits?
Not necessarily. Two trays can have similar ventilation areas but behave quite differently when loaded with small produce.
Large holes beneath the fruit
Large circular perforations are easy to identify as a potential problem. When the opening is wider than the effective supporting area required by a berry, the fruit may drop through, particularly when the tray is tilted or shaken.
Long slots along the bottom
Long ventilation slots deserve a different type of inspection. Their narrow width may appear acceptable, but elongated fruit can sometimes enter at an angle. Checking only one dimension of the opening can therefore give a misleading impression.
Perforations close to the edges
Fruit does not always remain evenly distributed. When a tray is moved or tilted, berries can collect near the sides. If large openings are positioned in these areas, some fruit may become trapped or escape.
For PET fresh fruit tray suppliers, the location and arrangement of perforations should be considered alongside their dimensions. Simply increasing the number of holes to improve ventilation does not necessarily produce a better tray.
How Should Tray Openings Be Adjusted for Different Fruit Sizes?
The most useful starting point is the smallest fruit that the customer expects to pack.
Suppose a blueberry order includes berries measuring approximately 10–16 mm. A tray that performs well with 13–16 mm berries should not automatically be approved for the entire order. The 10 mm berries need to be checked separately.
Buyers should provide actual samples where possible. Measurements taken from several fruits can establish the size range, while visual inspection helps identify differences in shape.
There is another detail worth considering: fruit is not always perfectly rigid or round. Soft berries may deform slightly under pressure, and irregular fruit can enter an opening in an unexpected position. A design that looks acceptable on a drawing may behave differently once the tray is filled.
The supporting ribs also deserve attention. If they are too far apart, small fruits may settle between them. If they are poorly positioned, berries can roll toward the perforations during handling.
An experienced OEM fresh tray factory should therefore review the opening width, rib spacing, and contact area together. There is no single hole measurement that works for every type of small fruit.
How Can Tray Design Balance Fruit Support and Ventilation?
Reducing the size of every opening is not always necessary. In many cases, changing the distribution of openings can solve the problem without making the tray unnecessarily enclosed.
Give the bottom more reliable support
Raised ribs or a more continuous supporting surface can help keep small fruits away from vulnerable openings. The ribs should be positioned according to the fruit's natural resting position rather than added simply to make the bottom look stronger.
Use different opening sizes in different areas
A tray does not have to use identical perforations throughout its entire surface. Smaller openings can be used beneath the main fruit-loading area, while other suitable areas retain larger ventilation openings.
This allows the design to address fruit retention without sacrificing every available airflow path.
Consider shallow molded positioning areas
For products that move easily, shallow depressions can help keep fruit from rolling across the bottom. They may be useful for certain berry trays, especially when consistent retail presentation is important.
However, deeper compartments can reduce loading efficiency and create difficulties for automated packing. Their value needs to be judged against the customer's actual filling process.
Move some ventilation to the sidewalls
Where the application allows, sidewall openings can provide additional airflow without placing every perforation directly beneath the fruit. The cooling requirements of the produce must still be considered before making this change.
ODM fresh produce tray suppliers should evaluate these options according to the fruit, packing line, and transportation conditions rather than applying the same structure to every tray.
How Can Buyers Check Whether a Fresh Tray Works Before Ordering in Bulk?
A sample tray should be tested with the fruit it is actually intended to hold. Empty-tray inspections cannot reveal whether small berries will slip through once the packaging is in use.
Start by filling several samples with the smallest available fruits. Check the bottom and side openings carefully. Look for berries that fall through, become wedged in slots, or sit unevenly on the supporting ribs.
Next, move the filled trays through the same handling steps used in the packing operation. Tilt them gently in different directions and observe whether fruit collects near the edges. If the trays will travel long distances, vibration and stacking tests can provide a more realistic picture of their performance.
Also inspect the trays after stacking. Thin plastic sections may deform under load, changing the shape of openings or reducing the support available beneath the fruit.
For fresh tray manufacturers serving wholesale produce packers, these practical checks are more useful than approving a design solely from a drawing or a set of empty samples.
What Information Should Buyers Give Their Fresh Tray Supplier?
When requesting a new tray, avoid sending only a product photograph and the required external dimensions. These details rarely explain why the current packaging is losing fruit.
A more useful specification includes the smallest and largest fruit sizes, fruit shape, approximate loading quantity, and whether the tray will be filled manually or by machine. Buyers should also explain how the trays are stacked and transported.
For custom PET berry tray suppliers, photographs of the existing tray can help identify where the openings are located, but physical samples are even more valuable when structural changes are being considered.
If one tray needs to accommodate several fruit sizes, make this clear before sampling. A design that works for large blueberries may not hold smaller berries securely, even if the two products look similar.
The final approval should come after testing with actual produce, particularly the smallest size expected in regular shipments.
A fresh tray needs to do two jobs at the same time: allow sufficient airflow and keep the fruit where it belongs. Getting that balance right depends on the relationship between fruit size, opening layout, and supporting structure. For buyers, checking these details during sampling is far less costly than discovering the problem after thousands of trays have entered the packing operation.
