Expressed in cc/m²/day, OTR is the single most important spec for product stability. A lower OTR means less oxygen permeates the film, directly extending shelf life and preventing discoloration and rancidity in sensitive products like cooked ham.
Plastic casings are designed to shrink at specific temperatures (e.g., 80°C+). The shrinkage ratio (e.g., 20%) determines how tightly the casing conforms to the product. Correct specification eliminates wrinkles and voids, maximizing yield and presentation.
Measured in MPa or kPa, this indicates the casing’s ability to withstand internal pressure during stuffing and cooking without failing. High strength is vital for large-diameter products and high-speed processing.
A large cooked ham requires a high-shrink, very low OTR casing. A cheese block may need a medium-shrink, high-moisture barrier film. Always start with the product’s processing steps and desired shelf life.
Different polymer blends (e.g., polyamide/ethylene-vinyl alcohol/polyethylene) create different performance profiles. Your supplier selects the laminate structure to achieve the targeted OTR, shrinkage, and mechanical strength.
The casing diameter must match your stuffing horn and desired finished product size, accounting for shrinkage. “Layflat width” is the key purchasing dimension for flat casings.
Always obtain a Technical Data Sheet (TDS) from your supplier. Learn to read the key values for OTR, shrinkage, and strength, and ask questions if specifications are unclear or seem mismatched to your application.
Lab specs are a guide; real-world validation is crucial. Test samples under your exact conditions—stuffing pressure, cooking cycle, chilling—to confirm the casing performs as needed for yield, peelability, and final appearance.
Leverage their expertise. Share your product details and challenges. A good technician can translate your needs into precise casing specifications and recommend a grade that optimizes performance and cost.
