Aseptic processing minimises the chance that donor tissue can be contaminated during preparation. Aseptic processing involves specific, validates protocols which include mechanically agitating the tissue to remove blood, lipids and cells; cleaning them with detergents, antibiotics, antifungals or chemical disinfectants; and cutting/shaping them in a clean room. These protocols are validated through biological testing of the tissue and environmental testing of the equipment and packaging. While aseptically processed allografts are prepared and tested in ways which reduce microorganism presence, aseptic processing cannot be labelled as sterile and can only yield a Sterility Assurance Level (SAL) of 10-3; denoting a 1 in 1,000 chance of graft contamination.