Cold Chain Performance: Comparing Corn Starch (CPLA) and Kraft Containers for Frozen Food Packaging
Evaluating Material Performance in Sub-Zero Environments
Frozen food packaging demands materials that can withstand sub-zero temperatures without becoming brittle or suffering freezer burn. CPLA cutlery and Kraft paper containers (especially those used for meal kits) offer distinct advantages and disadvantages in the cold chain, requiring careful selection based on whether the product is packaging or the food itself.
1. CPLA Cutlery in Frozen Environments
The strength of CPLA changes drastically when exposed to freezing temperatures.
Brittle Point: Most plastics and bio-plastics become brittle at sub-zero temperatures. CPLA, designed for stability up to 85°C, retains its structure, but its impact resistance drops significantly around 0°C.
Client Warning: CPLA cutlery should not be used to scoop frozen foods (like hard ice cream) directly from the freezer, as the utensil is prone to snapping due to its inherent rigidity under cold stress.
Best Application: CPLA cutlery is suitable for inclusion within frozen meal kits for later use, provided the food is fully thawed or heated before the utensil is used.
2. Kraft Paper Containers for Frozen Food
Kraft paper is widely used for frozen meals, but its success depends entirely on the specialized coating.
Moisture Barrier Imperative: Freezer burn occurs when moisture escapes and sublimates. Standard bio-lined Kraft paper is not sufficient. Specialized freezer-grade coatings (often high-density polyethylene or wax derivatives) are required to create a total moisture barrier and prevent the paper fiber from degrading from prolonged exposure to ice and cold.
Freezer-to-Oven Paperboard: We supply high-grade, thick-walled paperboard trays specifically designed to transition directly from the freezer into an oven (after the lid is removed). This provides maximum convenience for prepared meal clients.
Insulation: The fibrous nature of Kraft paper provides excellent insulation during the thawing phase, helping to slow down the temperature change.
3. The Cold-Chain Winner
When packaging the food itself, the Kraft Container (with freezer coating) is the superior choice due to its high moisture barrier and stability under temperature extremes.
4. Condensation Risk upon Thawing
Both materials face a final threat when removed from the freezer: condensation.
Post-Freezer Condensation: As the frozen package warms, condensation forms on the surface. CPLA is vulnerable to moisture absorption, and the paper container can temporarily lose strength.
Mitigation: We recommend placing the frozen Kraft container into a sealed plastic bag or secondary paper bag during the thawing process to control the condensation rate, preserving the container's structural integrity.
Conclusion
Choosing the right material for frozen food packaging requires understanding the specific demands of the cold chain. While CPLA cutlery serves well as an accessory in meal kits when used after thawing, Kraft paper containers with specialized freezer-grade coatings excel as primary food packaging due to their moisture barrier properties and temperature stability. By selecting materials based on their cold-chain performance characteristics, businesses can ensure product quality and customer satisfaction throughout the frozen food lifecycle.