Natural Preservatives for Postharvest Spoilage Control: Efficacy, Mechanisms, and Industrial Scalability

Abstract

Postharvest losses consume a substantial fraction of global fruit and vegetable production—commonly cited in the range of 20–40% for disease-driven decay and up to 28–55% overall—with microbial spoilage by fungi such as Botrytis cinerea, Penicillium spp., Rhizopus stolonifer and Monilinia spp. as the dominant biological driver, and an estimated global economic burden of the order of US$150 billion annually. Reliance on synthetic fungicides is increasingly constrained by pathogen resistance, regulatory withdrawal and consumer resistance to chemical residues, motivating a shift toward natural preservatives. This review provides an integrated, critical assessment of natural preservatives for postharvest spoilage control across three linked dimensions: efficacy, mechanisms and industrial scalability. Five principal classes—essential oils, polyphenol-rich plant extracts, microbial biocontrol agents, generally-recognised-as-safe (GRAS) compounds, and edible coatings—are compared with respect to their activity against the major postharvest pathogens. Reported decay reductions frequently reach 60–93%: for example, thyme and oregano essential-oil dips can lower grey-mould lesions in strawberries by roughly 70–90%, antagonistic yeasts and bacteria reduce disease incidence by 60–85% through competition and volatile organic compounds, and natamycin achieves up to ~93% control of citrus green mould.
Mechanisms are shown to be multi-target—membrane disruption, enzyme and ATPase inhibition, reactive-oxygen-species induction, quorum-sensing and biofilm interference, nutrient and space competition, and elicitation of host defence—which underlies both broad-spectrum activity and a low propensity for resistance. Industrial translation is examined through registered commercial products (Bio-Save, Shemer, Nexy, BoniProtect, natamycin) and the barriers of cost, formulation stability, regulatory approval and supply-chain integration. Shelf-life extensions of two- to fourfold are documented across diverse commodities. The review concludes that natural preservatives are technically mature for several applications but require standardised efficacy testing, robust formulation, and clearer regulatory pathways to achieve wide commercial adoption.