Recent Advances in Food Process Engineering

Precision fermentation uses engineered microorganisms to manufacture defined food ingredients, but successful expression does not establish industrial feasibility or environmental advantage. This critical narrative review examines the coupled biological, engineering and assessment decisions that determine whether fermentation-derived ingredients become functional, affordable and resource-efficient products. The scope centres on recombinant dairy and egg proteins, with oligosaccharides, sweet proteins, haem proteins and tailored lipids used to expose differences between product classes. Accessible scholarly literature was selected through topic-specific searches, citation tracing and bibliographic verification, and appraised according to experimental scale, product characterisation, process completeness and the transparency of economic and environmental assumptions. The evidence supports microbial production of several functional food proteins, while showing that secretion, post-translational modification and recovery can remain limiting even when total expression improves. Large-scale performance depends on oxygen delivery, heat removal, broth rheology, feeding gradients and population stability; laboratory titre alone therefore provides an incomplete basis for investment. Downstream processing must reconcile impurity control with retained functionality, because maximising purity can increase losses, water consumption and cost without improving the intended application. Environmental assessments identify electricity, carbon substrates, utilities and allocation choices as major determinants, with some fermentation scenarios outperforming agricultural comparators and others offering similar or higher burdens. These findings do not support a universal sustainability ranking. The review develops an integrated decision framework based on saleable functional output, demonstrated process robustness and comparison with an explicitly defined incumbent ingredient. Immediate priorities include paired fermentation–recovery experiments, representative scale-down testing, transparent process inventories and food-matrix validation. Precision fermentation is best understood as a set of product-specific manufacturing routes whose contribution to sustainable food production must be demonstrated across the complete process chain.