A considerable amount of literature exists regarding design strategies and methodologies for large scale chemical engineering processes. However, the majority of the effort has focussed on petrochemical industries. Consequently, design strategies have been tailored to the specific requirements of these industries. Process design for food industries presents a number of unique challenges and problems, many of which cannot be addressed by existing petrochemical-based design methods. The principles of operation of most dairy processes are well known, but procedures for their design are not published in open literature. Large scale dairy design is often a mixture of heuristic and ad hoc methods, relying heavily on the experience of the designer. This thesis compares petrochemical and dairy processes, and considers points of similarity and difference. It was identified that petrochemical processes were typically centred around reactions, whilst dairy processes were mainly focused on separation and blending of selected components. For this reason, it was determined that petrochemical methodologies were not particularly relevant to the dairy process design. This study presents a new conceptual methodology for developing and assessing dairy process flow sheets. The methodology considers possibilities for integration of material, energy, water, time and the environment, between and within processes used in the dairy industry. It also considers opportunities and requirements for integration and provides the fundamental process understanding required when developing the new conceptual design methodology. The methodology is presented using four case studies covering small, medium and large scale processing operations. These case studies illustrate that the new methodology makes it possible to develop process designs in a more structured manner. More importantly, it enables integration opportunities for all process and product lines, particularly for medium and large-scale operations where a structured approach is required to systematically identify and assess integration possibilities. This thesis lays the foundation for dairy process design by introducing the evolution of conceptual process synthesis using a top-down framework to complement subsequent detailed design when required. This methodology represents a significant improvement over the current methods available for chemical process design in the dairy industry.