Sterling Anthony, CPPCold supply chains protect the quality, safety, and efficacy of a diverse category of temperature-sensitive products. Examples include perishable foods and beverages, pharmaceuticals, biologics, chemicals, and flowers. Packaging is an indispensable logistical component of cold supply chain management. Leveraging packaging for cold supply chains requires an understanding of the options, along with the factors that bear on decision-making.
Cold chain packaging is classified as active or passive. The former is powered by electricity, refrigeration for example. The latter, which is the focus of this article, relies on insulation, in combination with such additions as ice, dry ice, and gel packs.
Tapes designed for cold chain use are used to seal boxes, under refrigerated or freezing conditions. The tapes remain flexible, without the stiffening that can cause conventional tapes to lift along the edges. Closure-security protects the insulating capabilities of a container.
Stretch wrap engineered for cold chain use provides high cling and good tear resistance. Conventional stretch wrap becomes brittle at low temperatures and the resulting loss of holding strength can compromise the stability of palletized loads. Cold chain stretch wrap is produced as a blown film, because of its superior performance over cast film.
Wax-impregnated corrugated cases combine insulation with structural strength and water resistance, for such applications as seafood, meats, and produce. Applied on the interior and exterior of the box, the wax coating protects the cases’ fibers from the weakening effects of melting ice and condensation. Such allows the cases to be stacked without threat of collapsing.
Expanded polystyrene (EPS) provides lightweight, inexpensive insulation, whether as a formed container or as a liner (e.g. inside a corrugated shipper). But EPS has low impact resistance and is easily damaged, which can compromise its insulation capabilities, and it is criticized by environmentalists. The industry’s responses stress that the material is 98% air and is recyclable but claims of being biodegradable or compostable are challengeable.
Typically, expanded polyethylene (EPE) is valued for its cushioning properties. However, it is a better insulator than is EPS, in addition to providing better impact resistance and better moisture resistance. But like all petroleum-derived materials, it’s attacked on grounds of sustainability.
Polyurethane foam (PUR) is superior to EPS and to EPE as an insulator, having a higher thermal resistance (R-value) than the other two. It also has good cushioning properties, whether in the form of inserts or whether injected.
Vacuum-insulated panels (VIPs) are thin structures that are placed inside containers for insulation and thermal resistance. Their construction consists of a core material, embedded inside a multi-layer barrier envelope, evacuated in a vacuum chamber, and sealed. Because of their thinness, the panels leave more utilizable space.
Other options that are promoted on sustainability are made of paper, cellulose, cotton, cornstarch, just to name several. They take the forms of inserts, liners, and panels. Their various claims include recyclable, biodegradable, compostable, and reusable.
While the preceding is not offered as an exhaustive list, it more than implies this question: How should a decision-maker choose the right cold chain packaging? The answer is: “With a stepwise systems approach, based on product-specific considerations.”
Step 1: Determine the temperature setting involved. Refrigerated temperatures, around 40°F, for example, impose temperature-control requirements that are different than those imposed by freezing temperatures of 32°F and below. The setting will need to be maintained continuously.
Step 2: Model the other logistical components—namely, transportation mode, warehousing/storage, and material handling. The three are performed under conditions of temperature (and humidity) that affect packaging’s insulation and control requirements. The trio also impose physical forces (e.g., vibration, shock, compression) that test the packaging’s resistance.
Step 3: Determine the time span during which temperature-control is needed. Is it a mere 24 hours? What about 48 hours? What about 72 hours or longer? The correlation between time and packaging is direct: the longer the time, the more enduring packaging’s temperature-control capabilities need to be.
Step 4: Identify plausible candidates. This is the point wherein solutions are formulated. The solutions can range from a singular choice from the previously discussed options to a customized combination therefrom.
Step 5: Calculate true costs. Options come with varying prices, making the challenge one of cost-optimization. It’s false economy for high-value products, such as vaccines and biologics (blood, plasma, tissues, organs), to be packaged in lower-priced packaging that permits product losses. It’s also false economy for lower-value products, such as certain produce, to be packaged in higher-priced packaging that yields no or negligible losses.
Step 6: Document and monitor. Technology exists that enables real-time visibility and accountability throughout the supply chain. Vested parties don’t need to wait for nor guess about information concerning the performance of their cold chain packaging. Sophisticated sensors and data loggers track temperature, humidity, and location. Want feedback down to the item-level and not just at pallet-load-level? There are smart labels that can provide it. High-tech documentation and monitoring provide the added advantage of facilitating compliance with federal regulations, such as those of the FDA and FSMA (Food Safety Modernization Act).
Sterling Anthony, CPP, consults in packaging, marketing, logistics, and human-factors. A former faculty member at the Michigan State University School of Packaging, his contact info is:100 Renaissance Center, Box-176, Detroit, MI 48243; 313/531-1875; [email protected]
Sterling Anthony, CPP
