Postharvest treatments with GRAS salts to control fresh fruit decay

Abstract

Control of postharvest diseases of fresh fruits has relied for many years on the continuous use of conventional chemical fungicides. However, nonpolluting alternatives are increasingly needed because of human health and environmental issues related to the generation of chemical residues. Low-toxicity chemicals classified as food preservatives or as generally recognized as safe (GRAS) compounds have known and very low toxicological effects on mammals and minimal impact on the environment. Among them, inorganic or organic salts such as carbonates, sorbates, benzoates, silicates, etc., show significant advantages for potential commercial use, such as their availability, low cost, and general high solubility in water. Typically, these substances are first evaluated in vitro against target pathogens that cause important postharvest diseases. Selected salts and concentrations are then assayed as aqueous solutions in in vivo tests with target fresh fruit. Laboratory and small-scale experiments are conducted with fruit artificially inoculated with pathogens, whereas naturally infected fruit are used for large-scale, semicommercial, or commercial trials. Another approach that is increasingly gaining importance is evaluating GRAS salts as antifungal ingredients of novel synthetic edible coatings. These coatings could replace the fungicide-amended commercial waxes applied to many fruit commodities and could be used for organic or “zero-residue” fresh fruit production systems.