Critical area and critical surfaces

Critical area – an area designed to maintain sterility of sterile materials. Sterilized product, containers, closures, and equipment may be exposed in critical areas such as the grade A area or a closed system.

Critical surfaces – Surfaces that may come into contact with, or directly affect, a sterilized product or its containers or closures. Critical surfaces are rendered sterile prior to the start of the manufacturing operation, and sterility is maintained throughout processing.