A cap and rigid bottle converts an expressed milk syringe from an open system to a closed system. The cap is in fluid communication between a breast pump and breast cup. The rigid bottle is attached to the bottom of the cap and the syringe is captured inside the bottom under the cap in a sealed environment. The pump provides varying positive vacuum to the cap and through the cap to the breast cup. Milk is drawn by the vacuum into the cap and flows by gravity down into the syringe. A passage between the interior of the syringe and the interior of the bottle equalizes pressure and allows the syringe to fill while maintaining a closed system, allowing a piston in the syringe to remain stationary. The closed system protects a mother's milk being pumped into a milk collecting syringe from air born contaminants.