The state of being free from disease-causing microorganisms, and the set of methods used to achieve and maintain it. In food processing, asepsis means sterilizing the product, the packaging, and the filling environment separately, then bringing them together without recontamination, the principle behind aseptic cartons of milk and juice that keep for months unrefrigerated. In surgery and medicine it means sterile instruments, disinfected skin, and barriers against airborne microbes. The concept transformed both fields: before aseptic technique, canned food spoiled unpredictably and surgery killed through infection. Maintaining asepsis demands validated sterilization, controlled environments, and disciplined handling, since a single lapse reintroduces the microbes the entire system was built to exclude.