Minimal manipulation:

(minor processing including purification, centrifugation, washing, preservation, storage)-the Food and Drug Administration (FDA) argues that it has the authority to regulate anything beyond minimal manipulation and homologous use:

• For structural tissue, processing that does not alter the original relevant characteristics of the tissue relating to the tissue’s utility for reconstruction, repair, or replacement
• For cells or nonstructural tissues, processing that does not alter the relevant biological characteristics of cells or tissues