Many of the foods we eat are of microbial origin or contain constituents produced by microbial fermentation. This chapter considers the biotechnological problems associated with growing these producing strains, most of which are aerobic organisms, in large scale fermenters. It discusses how rational fermenter design is a crucial component in providing them with the physical environment for optimal desirable metabolite production, which with the filamentous fungi is often related to their morphological form. It also discusses how some of the problems in achieving this can be ameliorated by innovative fermenter configuration. Carefully selected examples are used to illustrate the practical application on an industrial scale of these philosophies and suggestions are made about how fermentation technology is likely to change in the future to satisfy the increasing demands for highly nutritious and safe foods for human consumption.