Chemical Migration Test Protocols for Modified Dispersion Coated Packaging
Chemical migration testing for dispersion coated board requires single-sided extraction cells and post-crease migration proofs to account for score-line breaks.
TTC Approach
Toxicological Threshold
Risk assessment frameworks establish acceptable human exposure thresholds for uncharacterized chemical substances based on structural chemical classifications. Utilization of the TTC approach allows safety assessors to evaluate non-intentionally added substances migrating from paperboard packaging when toxicity data is absent. The methodology groups chemical structures into Cramer classes to assign conservative human exposure thresholds below which toxicological risks remain negligible.
Genotoxic structural alerts require extremely low exposure limits.
Exposure Assessment
Evaluating packaging migrants using the TTC approach requires combining quantitative migration data with estimated daily dietary consumption figures. Structural evaluation classifies target compounds into low, intermediate or high toxicity classes based on functional groups and molecular reactivity. For Cramer Class I substances like simple aliphatic compounds, the human exposure threshold reaches 1800 micrograms per person per day.
High-concern Cramer Class III compounds with complex or reactive structures carry a much lower threshold of 90 micrograms per person per day. Substances bearing DNA-reactive genotoxic structural alerts face a stringent threshold of 1.5 micrograms per person per day. If calculated dietary exposure falls below the corresponding threshold, further expensive bio-assay testing is deemed unnecessary.
The methodology does not apply to organophosphates or heavy metals.
Safety Evaluation
Regulatory authorities accept conservative exposure thresholds to streamline safety evaluations for trace non-target migrants in food contact materials. Applying the TTC approach enables paper manufacturers to demonstrate compliance for trace packaging impurities without conducting full animal toxicity studies. Risk management dossiers incorporate threshold calculations to validate the safety of recycled paperboard for food packaging applications.
Analytical sensitivity must detect migrants at concentrations below applicable threshold limits.