Consumer preference for more environmentally responsible packaging, corporate sustainability goals, and tightening regulatory restrictions are driving an evolution in fresh produce packaging from plastic to paperboard alternatives.

Paperboard packaging offers a host of benefits at many stages of the value chain.

• Contributes to the circular economy: Unlike plastics produced from finite fossil fuel resources, paperboard packaging is made primarily from renewable, wood-based fiber.
• Highly recycled: Paperboard packaging is the most widely recycled material in the world, with a rate of around 80 percent in both the U.S. (EPA 2020) and Europe (Eurostat 2021).
• Reduces greenhouse gas emissions: In specific applications, paperboard materials have been shown to reduce carbon emissions compared to plastic counterparts—minimizing the environmental impact of packaging (Savvypack, 2021).
• Meets consumer preferences: Studies show that consumers perceive paperboard packaging as better for the environment. Here’s just one example.
• Branding potential: Paperboard’s versatility offers superb structural and graphic design potential for great on-shelf differentiation.

Despite these benefits, paperboard packaging must perform well to minimize food waste. UN data shows that roughly a third of all food produced globally goes uneaten, which has a huge carbon cost—every kilogram of food sent to landfill generates the same amount of carbon emissions as 25,000 plastic bottles.

Does paperboard packaging for fresh produce offer an equivalent shelf-life to plastic?

At Graphic Packaging, we developed the ProducePack™ range of paperboard solutions for fresh produce. One of these solutions is the ProducePack™ Punnet tray, a top-seal tray designed for applications like tomatoes, mushrooms, berries, and grapes.

One of the most frequently asked questions from customers is:

“Does your punnet tray offer the same shelf-life as my plastic punnet?”

Feedback from eight tomato growers who had performed shelf-life tests on the punnet tray confirmed that it did indeed offer equivalent shelf-life. Some even reported that the paperboard punnet offered better results than their plastic trays. It was important to confirm these findings with an independent test, so Washington State University were asked to help.

How the tests were carried out

The objective was to compare the shelf-life of grape and cherry tomatoes packed in plastic and paperboard punnet trays and each tray type was to be tested in ambient and chilled conditions.

The study analyzed 750 punnets of both grape and cherry tomatoes, with half of each packed in paperboard punnets and the other half in plastic punnets.

The packs were kept in a cooler for four days, before half were removed and kept at ambient temperature. The tomatoes were tested for internal temperature, softness, weight, wrinkling, and the presence of mold every other day.

Headline result: Significantly less mold growth occurred on tomatoes in the paperboard punnets

Mold growth

• Mold growth on cherry tomatoes in plastic was 61% higher than in paperboard in
• refrigerated conditions and 320% higher at room temperature.
• Mold growth occurred earlier in plastic punnets versus paperboard punnets.
• Overall, cherry tomatoes were more likely to exhibit mold growth than grape tomatoes, which exhibited minimal mold under either condition.

What Does It Mean?

The results confirmed that the paperboard punnet offers at least equivalent shelf-life for tomatoes, and offers superior results to plastic in some cases.

Although the relative humidity (RH) inside the punnets wasn’t measured, we can infer that the RH inside the paperboard punnets was lower than in the plastic punnets as they lost a greater amount of weight over the test period in all cases. It was concluded that the paperboard’s permeability, combined with the ventilation holes, allowed moisture and gases to escape, resulting in lower RH.

If you’d like to read the full study, you’ll find it here.