Evaluating casing quality is a systematic process. The following "Fourteen Quality Criteria" provide a reasonable basis for distinguishing between inferior and superior products.

Barrier Properties: Refers to the casing's resistance to oxygen, water vapor, and aromas. Superior barrier properties grant sausages a longer shelf life, prevent returns due to spoilage, and help retain freshness and flavor.

Structural Rationality: A well-designed casing structure provides an ideal package for the sausage.

Film Strength: Good mechanical strength withstands the demands of various filling and clipping machines, thereby reducing film breakage during use.

Shrinkage Consistency: Indicates the uniformity of the shrinkage rate within the same roll or batch. Significant variation causes inconsistent lengths and diameters in sausages of the same specification, creating issues for packaging and sales.

Color Uniformity: For colored casings, even coloring enhances the sausage's visual appeal, making it more attractive to consumers.

Openability (Ease of Opening): Crucial for efficient filling. Poor openability makes mounting the casing on the horn and filling difficult, directly impacting operator efficiency.

Dimensional Accuracy: The deviation in folded diameter and thickness must be strictly controlled. Inaccuracies lead to uneven sausage diameters, and excessive thickness variation can cause bending and performance issues.

Film Transparency: For transparent casings, high clarity is vital for premium sausages. It allows consumers to see the meat texture clearly, boosting appeal and purchase desire.

Softness/Hardness Feel: A good hand feel facilitates use. Sausages have a fuller meat appearance after filling. For molded hams, a softer casing helps achieve well-defined, smooth shapes, whereas stiff casings can result in sharp edges and moisture release.

Film Gloss: A glossy appearance makes sausages bright and eye-catching on the shelf, easily attracting customers.

Meat Adhesion & Lamination:

(1) Adhesion to the meat reduces moisture purge, preventing deterioration in taste.

(2) Bonding strength between the different layers of the casing film ensures structural integrity and stable performance.

Interlayer Bonding Effect: (Note: This essentially repeats point 11.2. It can be considered consolidated). Refers to the adhesion between layers, ensuring a stable structure and consistent performance.

Roll Flatness: Reflects the uniformity of the film's thickness and is indicative of overall product quality.

Packaging Seal Integrity: The outer packaging must be tightly sealed to prevent moisture absorption and have sturdy boxes to protect the casings from damage.

Applying the casing might be the final step in sausage production, but overlooking its importance can cause significant problems. Therefore, selecting the right casing requires comprehensive consideration: choose high-quality casings with a good cost-performance ratio and ensure they are suited to your specific sausage requirements. Correct usage is also essential to allow the casings to perform effectively and deliver substantial economic benefits.