Fermented foods are part of many traditional diets and consist of a great variety of food products having exotic sensory properties and/or nutritional plus medicinal values. Technically such products are the result of enzymatic conversions of different plant and animal tissues or their derivatives caused by the so-called spontaneous growth of microorganisms or growth of one or more appropriately selected and curated strains of microorganism (s). Increasing scientific evidence of their health benefits is inspiring new fermentation process development using novel starter cultures (e.g., probiotic microorganisms), matrices (different animal and plant materials), bioreactor systems (e.g., in a tank), and specific fermentation conditions (e.g., non-isothermal temperature). Maintaining safety and consistent quality parameters in every batch of fermented food is a challenge for its commercial processing. This chapter aims to discuss starter culture development, fermentation process design and optimization, post-fermentation processing, and packaging plus shelf life assessment of fermented products. A blend of scientific and engineering principles of food and dairy fermentation will facilitate new fermented product development.