Recent Advances in Food Process Engineering

Non-thermal preservation technologies have matured individually, yet each retains a characteristic ceiling: high-pressure processing struggles with bacterial endospores, pulsed electric fields depend on matrix conductivity and cell size, cold plasma acts mainly at surfaces, ultrasound is energy-intensive at lethal intensities, and ultraviolet light is defeated by turbidity. Combining these processes is widely presented as the route past those ceilings, and the combination literature has expanded rapidly. This critical narrative review evaluates whether the evidence supports that expectation, and on what terms. Peer-reviewed literature published between January 2003 and 8 July 2026 was identified through structured searching of open scholarly indexes and citation registries, supplemented by backward and forward citation tracking, and was appraised for mechanistic coherence, methodological adequacy and engineering realism rather than assembled descriptively. The evidence indicates that reproducible enhancement is concentrated in pairings whose primary lethal targets differ and whose delivery constraints are complementary, particularly ultrasound with plasma-activated liquids, ultrasound with ultraviolet light, and ultraviolet or ultrasound pretreatment before high-pressure processing. Enhancement is far less consistent where two processes converge on the same target, and combinations that improve microbial lethality do not reliably improve nutritional or sensory outcomes; several rigorous comparisons report that a single optimised process outperforms its combination on quality endpoints. Three weaknesses recur across the field. Synergy is asserted without a declared additivity baseline; single-technology comparators are rarely matched for delivered energy or equivalent lethality; and sublethal injury is seldom quantified, so apparent enhancement may reflect enumeration artefacts rather than lethality. Engineering integration remains the binding constraint, because batch pressure vessels, continuous electrical treatment chambers and surface-limited plasma or photon sources impose incompatible residence times and throughput. Priorities are proposed for baseline-anchored synergy reporting, equivalent-lethality comparators, injury-aware enumeration, and pilot-scale demonstration of sequencing feasibility.