Chinese National Food Contact Plastic Declaration File Inspection Workflow
Chinese food contact plastic declaration files require accredited GB standard migration reports, complete additive SML tracking, and strict lot traceability.
Repeat-Use Exposure Testing
Meaning
Specialized compliance testing regime evaluates chemical migration from reusable plastic articles across multiple consecutive exposure cycles to ensure chemical extraction declines or stabilizes over time. Required under European food contact framework regulations for multi-use items like food containers and reusable water bottles, repeat-use exposure testing subjects a single sample to three sequential migration periods using fresh food simulant for each cycle. Compliance requires that chemical migration in the third test period does not exceed regulatory limits and does not exceed levels measured in the second period.
The protocol applies exclusively to multi-use items and excludes single-use packaging.
Cycle Sequence
Successive exposure periods simulate repeated washing and food contact throughout product service life. Executing repeat-use exposure testing involves maintaining constant temperature and contact time across all three testing stages. A decreasing trend in specific migration from the first to the third exposure period demonstrates structural stability of polymer additives.
Rising migration values in later cycles indicate matrix degradation or additive hydrolysis during service.
Additive Depletion
Surface depletion of antioxidants and plasticizers occurs as extractable molecules leach out during initial contact cycles. Analytical results from repeat-use exposure testing show whether surface layer migration reaches steady-state equilibrium. High initial migration that fails to decrease suggests inadequate chemical bonding of additives within the polymer matrix.
Material formulations failing third-cycle test criteria cannot receive clearance for repeated food contact applications.
Degradation Assessment
Thermal and mechanical stress during repeated dishwasher cleaning alters polymer surface morphology. Conducting repeat-use exposure testing verifies that environmental stress cracking does not accelerate chemical leaching over extended usage periods.