Closing the Lid on Clamshell Produce Packaging for Good

By Mike Terry
Posted In : produce, produce packaging, sustainable produce packaging, tray sealing and forming, produce packaging trends, tray sealing, clamshell packaging
Clamshell Salad Package

Since its invention in the 1970s, clamshell packaging has provided just the right amount of protection, preservation, and perforation for smaller varieties of produce. They serve up a feast for the senses and allow respiration to present and maintain fresh, healthy-looking fruits, vegetables, and specialty greens.

But the reign of king clamshell may be coming to an end.

Produce packaging is experiencing a major shakeup as many modern consumers and retailers close the lid on the plastic packaging format for good, choosing more sustainable options, such as tray seal packaging, for their produce.

“We’ve seen a significant move away from clamshell packaging towards tray sealing and forming, dictated by producers and retailers,” said Carlo Bergonzi, Tray Sealing Product Manager for Harpak-ULMA Packaging. “Tray sealing and forming replaces the rigid snap lid feature of the clamshell with a flexible film seal. This transition offers various advantages to traditional packaging right away.”

What advantages could be so significant as to unseat a packaging institution that has been the go-to for decades?

15% Reduction in Packaging Materials

From the onset, applying a flexible film seal instead of the rigid clamshell lid creates packaging that is better for the planet and your bottom line. A reduction in materials means reduced costs, sustainability savings, and several steps forward in achieving aggressive sustainability goals set by most retailers for 2025 and beyond.

Tray Sealed Mixed Greens

Optimal Marketing and Brand Messaging

Opting for tray sealing vs. traditional clamshell packaging for produce helps your brand create and contribute to the circular economy by improving sustainable material recycling and making less waste. You’re also creating a relatable and desirable platform for your message to better reach modern eco-conscious consumers.

From a production perspective, tray sealing also offers improved opportunities for better package design, peel and reseal capabilities, and improved product shelf life and preservation.

“There is just less, said Bergonzi. “The material cost per package for tray sealing and forming is less. You are using less from a recyclability and sustainability standpoint. And the film seal allows for registered features – artwork, peel reseal film, die cuts, and so much more.”

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Early in the 1990s, produce giant Driscoll’s all but introduced plastic clamshell packaging for produce like raspberries, blueberries, strawberries, and cherry tomatoes. Clamshell’s perforated design allowed more airflow and better respiration to keep items fresher for longer, achieving maximum freshness when refrigerated.

More than just function though, Driscoll’s was focused on sustainability from the onset, directing their suppliers to create their clamshell packaging from 80% rPET from recycled bottles (including 40% pre-consumer content, 30% rPET from bottles, and 21% virgin plastic).

However, the process was not an easy one and none of their materials came from other thermoformed plastic clamshells – an ongoing and significant sustainability concern with plastic clamshell packaging.

Driscoll’s recognized this gap and the lost opportunities in thermoform-to-thermoform recycling and decided to collaborate with suppliers, materials recovery facilities (MRFs), and The Alliance for PET Thermoform Recycling, to remove those barriers.

The fruits of their efforts? A 9% rate of rPET thermoform packaging in their clamshell packaging (whereas before, it was 0%).

Their success has become a model for other challenging material-specific recycling streams. But that was just the beginning.

Today, Driscoll’s pilots new packaging alternatives to clamshell packaging – including corrugated cardboard containers and sustainable tray sealing – to optimize product preservation, prevent food waste, and minimize environmental impact by reducing plastics by up to 30%.

Is Driscoll’s continued altruistic transformation simply a yen to be as green and sustainable as they can be for 2023 and beyond?

Not entirely.

Along with the wasteful design of clamshell packaging, Driscoll’s realized there are significant benefits related to tray handling and transportation of products from the field to the packaging facility that can be gained when transitioning from a traditional snap-snap-close clamshell to a tray sealed package.

“The punnets are more easily done without the clamshell in terms of logistics and packing before they’re even closed,” said Bergonzi.

Driscoll’s discovered that clamshell packaging may be practical and utilitarian for produce operations to a degree. However, they also saw the product through the packaging. They knew improving on such a simplified design in a time of shifting market change, like now, could take their brand further with a new generation of customers.


As a producer, you are always on the hunt for produce packaging that offers you the best chance to stand out on store shelves. You need to separate yourself from your competitors and optimize production, while also providing your customers with the most convenience, value, and produce preservation possible.

Navigating these processes and striving towards modern produce packaging goals can be a daunting challenge today. Yet adhering to traditional clamshell packaging for produce can make those goals almost impossible to achieve tomorrow.

Opting for innovation like tray sealing and forming and other forward-thinking packaging processes allows you to gain advantages you need for success in a changing market and packaging landscape. Reduced packaging materials and production costs, improved sustainability, and dynamic marketing are just the start.


Unlike the mono PET plastics of the traditional clamshell, tray sealing and forming gives you a variety of sustainable packaging formats – made from recyclable plastics, fiber, and paper – that reduce overall non-recyclable plastics in production and landfill volume. Using these materials is better for the planet, popular with consumers, and offers another essential benefit unique to the application: reducing carbon footprint via improved shipping logistics.

Platformer Plus

Tray sealing and forming technology allows you to create pre-formed trays in-house, making shipments denser as you transport flat blanks or roll stock. Denser shipments mean reduced freight costs and lower carbon emissions when transporting tray materials due to a dramatic reduction of the number of trucks on the road.

“Trays created on specialized forming equipment give you the same characteristics that a preformed tray would,” said Bergonzi. “However, unlike purchasing preformed trays, you’re able to utilize all the benefits of roll stock – reducing carbon footprint and the number of required trucks for shipping by a factor of EIGHT.”


The dramatic differences between traditional clamshell packaging and tray sealing and forming, and the drawbacks of the former, don’t end at sustainable materials or shipping. They can even be seen among the tooling and components of the machinery itself.

Whereas clamshell packaging is formed strictly on an industrial thermoformer with a packaging mold, advanced tray sealing and forming utilizes sophisticated equipment, tooling, and dies for maximum versatility and speed to market when creating custom packaging.

From an investment standpoint, a tray sealer is the more flexible asset, as minimal change parts in the tooling allow for sealing of a variety of different, sustainable, and alternative materials such as:

  • PET trays
  • Paper trays
  • Fiber trays
  • Molded fiber trays with liner
  • Pressed fiber skin trays with coating
  • And more

FlexibilityThis flexibility advantage is essential, as producers cite tooling changeover as one of the leading causes of production expense and downtime. Tooling can run as much as 6% top-line costs and accounts for more than 28 minutes of downtime on average at each packaging interval.

Versatile all in one tray seal tooling, reduces this time significantly, saving hundreds of thousands in annual tooling and production costs and providing optimal agility for your produce packaging.


Traditional clamshell packaging is made from varying grades of thermoformed polyethylene terephthalate (PET). While fully recyclable, the plastic recycling process is different from that of other, more standardized plastic bottles. Therefore, recycling clamshell packaging is more difficult to complete on a larger scale.

Additionally, recycling clamshell packaging is unavailable without considerable consumer buy in and effort to clean, wash, and adequately sort it at designated facilities. Even when clamshell recycling is possible, the process also depends heavily on the resources and recycling infrastructure of the geographic location.

Conversely, with renewable tray sealing and forming materials without a liner, namely PaperSeal, pulp fiber, or press board, you have more sustainable options that do not rely on end-user compliance. There is no washing or cleaning of the packaging. You simply remove the liner and recycle or compost the tray. These sustainability advantages align with the needs of the contemporary market and consumer trends and can help you achieve broader, eco-conscious commercial goals.


Plastic punnets have perforations and the plastic seal film from tray sealing acts as a simple dust cover to protect produce from contamination. While the plastic mono materials used in tray sealing do not need to meet any specific barrier requirements, they do provide improved flexibility and allows recycled packaging materials for optimized sustainability.

In addition to protection, plastic tray sealing and forming integrates cutting-edge technological improvements to reduce plastic packaging materials. This innovative technology for pre-cutting lidding film offers a modern packaging system which produces ZERO percent scrap.

“When you need a preformed tray for produce packaging, utilizing tray sealing and forming equipment allows you to reduce materials and carbon footprint in transport, said Bergonzi. “You are creating the preformed tray with the turned down flange, but with additional benefits such as denser packaging, fewer shipments, lower carbon emissions, and cost reduction.”


Alternatively, tray sealing also offers a variety of sustainable fiber and paper-based options for produce packaging as well. Innovations in paper-based tray sealing, like those showcased at the IFFA Conference in May 2022, and being released in 2023, are in constant development and allow for a broad range of exciting, sustainable features, including:

  • State-of-the-art leak-proof one-piece sealing flange with unique thickness and no discontinuities
  • Identical flange design tooling for paper and plastic trays
  • Flexibility in tray design and shape, including curved, round, and oval
  • Wide range of choices for board and films for chilled and heat treatment applications
  • Diverse format applications for MAP, skin packing, heat seal only, and more

Salad in PaperSeal Packaging

Moreover, unlike clamshell packaging, almost all fibrous paper-based packaging creates minimal environmental impact. Paper-based tray seal packaging with custom formatting reduces packaging plastics by up to 90%. Producers can add attractive curves to their packaging, offering essential features for graphic and non-graphic packaging needs, while providing unmatched sustainability.


It is true that tray sealing and forming processes have complex folding, printing, and manufacturing processes that creates higher associated costs than traditional clamshell packaging. As a result, tray sealing and forming’s sophistication requires a greater investment in equipment and materials overall.

However, you must consider many pricing factors and savings sources when comparing modern tray sealing applications and traditional clamshell packaging.

For example, tray sealing and forming can cost more, as it is more sustainable. However, diving deeper you will find it is almost comparable to plastics. You must account for the rising costs of materials due to inflation and the costs of certain resins involved in modern plastic production.

“Plastic pricing is, has been over the past year, and will continue to be very dynamic, said Bergonzi. “It is very much a moving target, but I would expect to pay more for a very sustainable package.”

Yet volume is going to scale, whether the materials involved are recycled plastics, paper, or plastic clamshell packaging. Anytime you have more volume, you get economies of scale on the materials.

If you have a successful sustainable package, and more customers purchase your product based on the new global shift toward sustainable packaging, it can offset the material costs of that sustainable packaging. In other words, material cost savings at higher volume can offset premium and sustainable package material upcharges as well as equipment costs.

With reduced cost margins, it will be easier for you to integrate sustainable packaging into your production and earn more customers based on the modern need for eco-friendly packaging alternatives.


Is the move away from clamshell produce packaging a foregone conclusion in the age of maximum sustainability?

Time, and retailers, will tell.

Many of today’s leading produce providers require improved tamper evidence from hermetic film seals in the wake of COVID-19. Others cite clamshell’s poor packaging performance in the field, precipitating a fundamental shift toward more secure, versatile packaging choices.

Most are strictly focusing on sustainability goals for the future. They have gone so far as to join alliances for sustainability and have publicly proclaimed lofty goals by 2030. They now must live up to those pledges for their customers and their brand. Tray sealing and forming for produce is becoming an integral part of that effort.

“It is a combination of elements, but the demand is there,” said Bergonzi. “The good news is when moving to a film seal from traditional clamshell packaging, most of the production line can be left unchanged. Sufficient footprint is required in the facility, but the tray sealing and forming equipment can be placed in-line with existing denesting, loading, and conveyance systems with minimal impact on the production line.”


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