Analytical Testing Requirements for Food Contact Packaging Barrier Coatings
Aqueous barrier coatings on food contact paperboard require accredited migration, extraction, and permeation testing matching real food simulants and shelf temperatures.
Cramer Class Classification
Molecular Evaluation
Toxicological prioritization of chemical migrants from food-contact paperboard relies on a decision tree that evaluates molecular structures to estimate hazard levels. This systematic method defines the Cramer class classification, which assigns substances to one of three classes ranging from low to high anticipated toxicity. Class one contains simple chemical structures with low oral toxicity, while class three represents substances with structural features that suggest significant toxicity or lack of safety data.
Each step in the decision tree asks specific binary questions about functional groups and carbon chain length.
Threshold Determination
Exposure limits for non-evaluated substances in paper coatings correspond directly to the assigned category. Substances grouped into class one are permitted at higher migration thresholds than those in class three, where the threshold of toxicological concern is extremely restrictive. These exposure thresholds allow packaging laboratories to screen unknown or non-intentionally added substances without requiring full-scale animal studies.
Compliance Impact
Analytical testing of paperboard extractables uses these structural categories to determine whether a compound requires further toxicological clearance. When migration testing identifies a compound that falls under class three, the packaging converter must obtain specific clearance or reformulate the barrier coating. This prevents non-compliant materials from reaching the food-packaging supply chain.