Reusable devices experiencing repeated fatty food contact require demonstration that lipophilic substance migration remains controlled throughout device lifetime despite aggressive extraction conditions. Multiple-use migration testing with D2 simulant through repeated cycles demonstrates long-term safety with fatty food contact revealing whether oil exposure causes progressive material degradation or maintains stable migration levels. This extended testing reveals whether repeated oil extraction causes material swelling or degradation increasing migration, demonstrates eventual stabilization as extractable lipophilic substances deplete, or identifies concerning trends requiring use limitations or enhanced monitoring. Essential for reusable devices contacting fatty substances validating safety throughout intended use duration, equipment used with lipid-based nutritional formulations demonstrating maintained compliance, and regulatory submissions requiring proof that repeated oil exposure doesn't compromise migration safety. For reusable medical nutrition equipment processing high-fat enteral feeds, testing validates that repeated lipid contact doesn't progressively extract additives through swelling, cleaning between uses adequately removes absorbed oils preventing accumulation, and material integrity maintains acceptable migration despite potentially plasticizing oil exposure. The serial D2 extraction approach simulates extended device use under challenging conditions, reveals whether protective barriers resist oil penetration throughout lifetime, and demonstrates whether initial elevated migration stabilizes to lower levels through extractable depletion. Manufacturing validation confirms material selections withstand repeated oil exposure without excessive migration increases, processing produces materials with migration stability under aggressive conditions, and design life determination accounts for migration behavior under repeated fatty food contact scenarios.