Second Edition, June 2025 -This document is a guideline for the hygienic design and cleaning of disc stack centrifuges used in the food and pharmaceutical industries. It describes the requirements, implementation and design principles for different types of disc stack centrifuges used for the separation of liquid fractions or the removal of solids from products. Specific terms for disc stack centrifuges are defined. The requirements for the materials and surface finishes in use as product contact surfaces are also specified. Recommendations for the avoidance of gaps, dead spaces, metal/metal contacts and other elements that can make cleaning more difficult are listed. Instructions on how to perform CIP (Cleaning in Place) cleaning of disc stack centrifuges are given. The importance of centrifugal force for desludging and cleaning the bowl is explained. Finally, specifications are given for validating the hygiene requirements and measures are outlined for carrying out a cleaning test to check the cleaning capability of the machine under normal operating conditions.