Biofilm formation is a prevalent contamination source in the dairy processing industry. It enhances the tolerance of bacterial cells and elevates the risk of product spoilage. Moreover, biofilms can present significant challenges to dairy processing equipment, thereby threatening the safety and efficiency of operations. In the dairy product processing environment, biofilms typically appear as mixed biofilms. Compared to single-species biofilms, mixed biofilms are characterized by high diversity, complex spatial distribution, strong antibiotic resistance and high adaptability to environmental conditions. Consequently, it is essential to comprehensively understand the formation mechanisms and characteristics of mixed biofilms and develop effective control strategies. This review provides an overview of the formation of common microbial biofilms and their mixed biofilms during dairy processing, describes the cellular interactions and characteristics, and finally outlines current common biofilm control measures. All of these efforts aim to provide valuable insights for reducing risks associated with mixed biofilms in the dairy environment.