Migration testing measures how much of a material moves from the food-contact surface into a food simulant under defined time and temperature conditions. It is the core of food-contact proof for both FDA and LFGB.

The report checks overall migration limits and, where relevant, specific-element limits such as lead and cadmium. The simulant and conditions are chosen to mimic the intended use, whether that is water, an acidic drink, or a fatty liquid.

Element	What the report shows
Overall migration	Total material transferred into the simulant
Specific elements	Limits for lead, cadmium, and similar elements

Because results depend on the material, the surface area, and the contact conditions, a report is valid only for the configuration tested. Changing a gasket, a coating, or a lid resin can invalidate the earlier result.

Practical takeaway: Ask for migration test reports that name your exact material combination and intended liquid type, not a generic factory report.