Search

Consumers worldwide have become more and more concerned about the quality of fresh, fresh-cut fruits, and vegetables. Product quality is a complex issue: it encompasses visual characteristics, such as size, color, shape, and defects, all encompassed in general appearance; physical and chemical properties, such as texture, and mineral and vitamin contents; and flavor and other organoleptic characteristics. Thus, fruits and vegetables are also appreciated for their beneficial health effects in humans. Once produce is harvested, postharvest handling practices do not improve the quality attained in the field; they can only slow down the rate at which deterioration occurs. Appearance, freshness, and sensory qualities of a product can play a principal role in a consumer’s decision to purchase, and can influence their perception by other senses.

Postharvest decay caused by fungal pathogens is one of the most important factors causing economic losses for the worldwide industry of fresh horticultural produce. Despite the positive results of the use of conventional chemical fungicides, alternatives for decay control are needed because of increasing concerns related to their widespread and continued use. Low-toxicity chemical alternatives evaluated for control of postharvest diseases of temperate, subtropical and tropical fruit, and fruit-like vegetables are reviewed. These compounds should have acceptable antifungal activity with known and very low toxicological effects on mammals and minimal impact on the environment. In addition, they should be exempt from residue tolerances on agricultural commodities. Authorities confirm these characteristics by approving them as food additives or preservatives or as generally regarded as safe (GRAS) substances. Among these, the most important are inorganic or organic salts, e.g. carbonates, sorbates, benzoates, paraben salts, etc., and composite edible coatings formulated with antifungal ingredients. Hydrocolloids (polysaccharides such as cellulose derivatives, alginates, pectins, or gums, and various plant proteins) and food-grade lipids are the main components of the matrix of composite coatings. Interesting antifungal ingredients for edible coatings include GRAS salts, essential oils, and antagonistic microorganisms. Low-toxicity chemicals of natural origin include plant extracts and essential oils, antifungal peptides and small proteins, and coatings based on chitosan or plant gels like those from Aloe spp. Efficacy and overall performance, advantages, disadvantages, limitations, and potential combinations of these alternatives in hurdle technologies for postharvest decay control are discussed.

Publisher Summary The chapter describes the possibilities of using physical means and particularly heat treatments, to suppress the development of Aspergillus, Penicillium , and Alternaria species responsible for the accumulation of mycotoxins. Aspergillus molds are found worldwide. The genus includes over 150 species, some of which may infect fruits and vegetables and are capable of producing mycotoxins that adversely affect humans and animals health via consumption. These include alfatoxins and ochratoxin A, both of which are found to be carcinogenic. Penicillium expansum , the causal agent of the blue mold rot, is a common postharvest pathogen on apples and pears worldwide. Furthermore, Alternaria is a cosmopolitan fungus commonly isolated from plants, soil, food, and outdoor and indoor air environment. The genus Alternaria currently contains more than 50 species, among which, A. alternata is the most common one. Alternaria species are some of the most prodigious producers of toxic secondary metabolites, producing over 70 compounds of varying toxicity.