Cold chain science hinges on correct temperatures

By Jorge Izquierdo, Contributing Writer

For many produce products, the right storage and distribution temperature is critical to maximum shelf life and profits.

Packaging that ensures products are maintained under frozen, refrigerated or chilled conditions plays a major role in preventing premature spoilage and food waste, enhancing food safety, extending shelf life and enabling wider distribution.

The market for temperature- controlled, or cold chain, packaging is growing and expected to expand at an 8% compound annual growth rate through 2030, according to a report from researchandmarkets.com.

A MATERIAL MATTER

Long used for temperature- controlled packaging, expanded polystyrene (EPS) is a hygienic and moisture-resistant insulator. It is lightweight and has excellent temperature control, shock prevention and stacking strength. Unfortunately, EP has come under criticism because it is a hydrocarbon-based plastic and is often found in single-use applications, which are not widely accepted by current curbside recycling programs in the United States.

However, curbside recycling acceptance is growing as return programs create circularity for the material. In fact, the United Nations Environment Program recently recognized EPS transport packaging, such as temperature-controlled shippers, as a material that is recycled in practice and at scale.

In addition, it should be noted that life-cycle analyses, which consider energy use, greenhouse gas emissions, depletion of non-renewable resources, water consumption and other factors, show EPS scores better than polypropylene or fiber-based alternatives due to its lightweight and energy-efficient production.

EPS packaging can also provide better protection of vitamin C levels, according to Korean Food Research Institute research.

Nevertheless, concerns about the sustainability of EPS have prompted produce processors to seek alternatives. This often has taken the form of plastic-free packaging made from fiber-based substrates. However, any potential EPS replacement should be carefully tested to ensure its performance provides sufficient shelf-life protection.

Whatever materials are chosen, it’s imperative to communicate sustainability attributes to all stakeholders, particularly consumers, so they understand the positive attributes of the measures taken, according to Sustainability and Technology – the Future of Packaging and Processing, a report published in May 2023 by PMMI Business Intelligence, a division of PMMI, The Association for Packaging and Processing Technologies.

CONTROLLING THE VARIABLES

Selecting temperature-controlled packaging can be tricky because temperature requirements vary widely depending on whether the produce has been processed or is destined to be sold fresh. Fresh produce can be especially challenging because optimum conditions can range from near freezing to about 60° F, depending on the fruit or vegetable being shipped.

Further complicating the situation, shipping and storage times can vary widely depending on transport method (truck, rail, ship, air) and distance to destination.

Help with temperature-controlled package design and selection is available from packaging providers, testing labs and organizations like the International Safe Transit Association (ISTA), which launched an online course, Principles of Cold Chain Packaging (CC 101), in February 2024.

“Cold chain packaging is a critically important field that requires constant innovation and education. CC 101 is a great way to learn the fundamentals and stay updated on the latest trends and best practices,” A.J. Gruber, president and CEO of ISTA, said.

The course, an overview of cold chain packaging, covers topics including distribution environment hazards, heat transfer, temperature- sensitive products and aspects of cold chain including packaging solutions, system testing and quality control.

Interactive modules, quizzes, videos and case studies enhance the learning experience and provide practical examples of cold chain packaging applications. The course fee is $395 for ISTA members and $495 for non-members.

Smart technology, such as data loggers, also plays a role in temperature-controlled packaging. Such devices can monitor conditions inside the package and provide early alerts to temperature excursions. Temperature- controlled packaging may also be equipped with temperature-sensitive labels, which are printed with thermochromic ink that changes color if threshold temperatures are exceeded.

STUDIES IN SUCCESS

To move toward circularity, a few producers, especially food delivery services, have adopted reusable and/or compostable packaging. Georgia-based Fresh Harvest, an organic produce and grocery delivery service with about 4,000 subscribers in the Atlanta area, relies on returnable packaging, ice packs, foil insulation and compostable materials.

Compostable kraft paper protects sensitive products from the ice packs, and produce is now placed in compostable, transparent, premade bags instead of single-use plastic film. Customers may compost the materials or include them with the returnable components for recycling by CompostNow, a local composting operation.

The resulting compost is used in the Fresh Harvest garden and sold to other customers. The reusable bins have proven robust, with the first units, which date to 2012, still in use.

Fresh Del Monte has begun using reusable plastic containers (RPC) for bananas to reduce food waste, carbon emissions and operational costs. Designed to replace the single-use corrugated containers traditionally used to ship bananas, the containers are expected to make multiple trips each year, last for 15 years and reduce the carbon footprint of the packaging by 90%.

“By emphasizing the reuse of packaging materials, we aim to reduce our environmental footprint while promoting a circular economy of plastics,” said Hans Sauter, chief sustainability officer and senior vice president of R&D at Fresh Del Monte.

Sauter said RPC reduces greenhouse gas emissions and addresses fruit quality and pallet shipping density, helping to ensure supply chain sustainability.