Cellular agriculture has become a popular method nowadays for producing alternative proteins. Although the technology is quite advanced, it still faces complex challenges, e.g., strain selection, downstream processing optimisation, safety and regulation, and consumer acceptance. In particular, the current downstream processing mode is adapting the purification process of pharmaceutical products, which have a high purity and are sold at a high price. This method is not feasible to be applied to food protein production. Therefore, developing scalable downstream processing plays a crucial role. It should consider not only process efficiency but also scalability. Then, the protein can be produced at an affordable price in mass production. In the current project, we explore downstream processing options that are applicable to recombinant milk proteins and single-cell protein production.