Purpose ‐ Environmental conditions in a food manufacturing plant have a great impact on food safety and product quality. The purpose of this paper is to discuss the various components that make up the environment or contribute to the quality of the environment. Design/methodology/approach ‐ The paper examines the way in which the air quality in the factory environment is defined, and discusses the affect that staff flow, product flow and factory finishes has on the environmental conditions in the factory. Findings ‐ There is no clearly defined guideline which adequately covers the environmental control of food plants. Originality/value ‐ The concept of defining food plant environments by way of cleanroom classification is relatively new in the food industry.