Tray sealing technology in fruit packaging

Tray sealing in fruit packaging involves closing product-filled containers with a layer of heat-shrink film. What exactly is tray sealing and what are the advantages of sealing punnets?

What is tray sealing?

Tray sealing is a packaging method in which a product placed in a tray (most commonly made of PET, APET, rPET or fibre) is sealed with a thin layer of film. The film has heat-shrink properties, meaning that when exposed to the high temperature and pressure generated by the sealer, it adheres to the edges of the tray, forming an airtight seal. This method of closing trays is an alternative to lids and is becoming the standard in the fresh fruit market.

Not just the fruit industry: applications of top-seal technology

The growing interest in tray sealing stems, among other things, from the versatility of tray sealers. The market offers a full range of sealing machines, from the simplest manual sealers to advanced, fully automatic tray sealers. Individual machines offer different ways of filling the sealed packaging. Here are the most popular variants:

• Atmospheric systems without gas modification — air remains inside; the selection of film with appropriate permeability and trays with suitable ventilation, matched to the respiration rate of the fruit. A simpler, energy-efficient and increasingly popular solution in the fruit segment.
• MAP (Modified Atmosphere Packaging) — a more advanced solution that involves replacing the air with a mixture of gases (CO₂, N₂, O₂) matched to the respiration rate of the specific product inside. Available in two versions: MAP-F and MAP-V.
• Vacuum Skin Packaging (VSP) — vacuum packaging, in which air is removed from the package.

Automatic sealing is fast, ensures high repeatability and allows labour costs to be reduced by eliminating manual lid application. It is also highly versatile: packaging sealed this way is not limited to fruit alone. Tray sealing is widely used by producers of meat, fish, seafood, ready meals, dairy products, snacks and sauces. Tray sealers are also used in the production of medical devices. They are used by airlines packaging meals for passengers, while manual sealers are used by restaurateurs fulfilling takeaway orders.

Retailers are choosing fruit packed with tray sealers

Why are retail chains increasingly moving away from traditional lids and replacing them with heat-sealed film? First, switching to top-seal technology allows businesses to reduce plastic consumption — in practice, a reduction of approximately 33% has been recorded compared to traditional trays closed with lids. Second, the seal ensures airtight closure and guarantees that the packaging has not been previously opened. A plastic lid offers no such guarantee. Third, the transparent film allows consumers to assess the quality of the fruit before purchase — and the experience of companies we work with is clear: customers value the ability to visually inspect the contents of a package when shopping. An additional benefit for the producer is the option to print on the film, making top-seal a potential brand communication tool.

Further advantages of tray sealing for fruit producers

1. Reliability and repeatability
   The heat seal provides airtight closure that can be relied upon during transport, in cold storage and on the shop floor. Unlike lids, a well-executed seal is stable and repeatable, enabling the entire distribution system to be fully automated.

2. High level of protection for delicate fruit
   A rigid tray closed with a layer of film protects delicate blueberries and soft fruit — strawberries, raspberries, blackberries — from bruising throughout the supply chain.

3. Material flexibility
   Tray sealing technology allows work with a variety of materials — APET, mono-material films, paper — without the need for major changes to the packaging line. Trays can also be made from different materials and in different sizes. This flexibility enables producers to respond quickly to changing market trends.
4. Automation and peak-season performance
   Tray sealing lines can be integrated in parallel configurations, maintaining throughput even during peak season. When the sealing process is well integrated with automated packaging, the number of unplanned stoppages decreases significantly — which has a direct impact on profitability during short harvest windows.

Who is tray sealing technology for?

Punnet sealing is most worthwhile for:

• soft fruit (strawberries, raspberries, blueberries, grapes, blackberries) sold to retail chains,
• producers and packaging companies focused on export, where retail chains require specific packaging formats and product shelf life,
• volumes that justify automation — particularly where production needs to scale up during peak season,
• plastic reduction — tray sealing enables a gradual transition to recycled materials and mono-material films without redesigning the entire line.

When is tray sealing in fruit packaging not the best solution?

Tray sealing has many advantages, but also a few limitations that potential investors should keep in mind. For the purchase of a sealer and tooling to be cost-effective, a company must have sufficient sales volume. For small fruit producers, investing in an top tray sealer will not be financially viable. It is also worth remembering that innovative, automatic tray sealers are sophisticated machines, and their integration, configuration and operation require trained personnel — all to avoid stoppages and errors that translate into product losses.

Want to find out whether purchasing an automatic tray sealer is the right step for your business? Fill in the form below and arrange a no-obligation consultation with one of our advisors.

FAQ — Tray sealing of fruit

What is tray sealing of fruit? Tray sealing of fruit is a packaging method that involves closing fruit in a tray with heat-sealed film applied by a sealer under heat and pressure. It replaces traditional plastic lids and is becoming the standard for packaging soft fruit in modern retail.

What variants of tray sealing are used for fruit? Among all, the three variants are frequently used for fruit: atmospheric systems without gas modification (film with appropriate permeability and a ventilated tray), MAP (Modified Atmosphere Packaging) in MAP-F and MAP-V versions, and Vacuum Skin Packaging (VSP), in which the film tightly wraps the product after the air has been removed.

Why do retail chains choose tray sealing over traditional lids? For three reasons: tray sealing reduces plastic consumption by approx. 33%, the heat seal guarantees airtight and tamper-evident closure — something a lid cannot provide — and the transparent film allows consumers to assess the quality of the fruit before purchase.

Which fruits are best suited to tray sealing? Tray sealing works best for soft fruit requiring mechanical protection: strawberries, raspberries, blueberries, blackberries and grapes. The rigid tray protects them from bruising throughout the supply chain, while the airtight film prevents moisture loss and contamination.

What are the main advantages of tray sealing for fruit producers? Tray sealing provides reliable and repeatable closure, high mechanical protection for delicate fruit, material flexibility (APET, mono-material films, paper, fibre trays) and the ability to integrate into parallel lines — enabling throughput to be maintained even at peak harvest season.

When is tray sealing not cost-effective? Tray sealing is not cost-effective for small producers selling directly with a short supply chain, where low volumes do not justify the cost of the machine and tooling. Automatic tray sealers also require trained personnel for integration and operation.