The science, development, and commercialization of postharvest biocontrol products

• Alternatives technologies to chemical fungicides are needed.
• Commercialization of biocontrol products is limited.
• Multiple components interact in the biocontrol system.
• The relevance of −omic technologies on the science of biocontrol is reviewed.
• The potential use of natural and synthetic microbial consortia is discussed.

Postharvest biological control agents as a viable alternative to the use of synthetic chemicals have been the focus of considerable research for the last 30 years by many scientists and several commercial companies worldwide. Several antagonists of postharvest pathogens have been identified and tested in laboratory, semi-commercial, and commercial settings and were developed into commercial products. The discovery and development of these antagonists into a product followed a paradigm in which a single antagonist isolated from one commodity was also expected to be effective on other commodities that vary in their genetic background, physiology, postharvest handling, and susceptibility to pathogens. In most cases, product development was successfully achieved but their full commercial potential was not realized. The low success rate of postharvest biocontrol products has been attributed to several problems, including difficulties in mass production and formulation of the antagonist, the physiological status of the harvested commodity and its susceptibility to specific pathogens. All these factors played a major role in the reduced and inconsistent performance of the biocontrol product when used under commercial conditions. Although many studies have been conducted on the mode of action of postharvest microbial antagonists, our understanding is still very incomplete. In this regard, a systems approach, that takes into account all the components of the biocontrol system, may represent the best approach to investigating the network of interactions that exist. Very little is known about the overall diversity and composition of microbial communities on harvested produce and how these communities vary across produce types, their function, the factors that influence the composition of the microbiota after harvest and during storage, and the distribution of individual taxa. In light of the progress made in recent years in metagenomic technologies, this technology should be used to characterize the composition of microbial communities on fruit and vegetables. Information on the dynamics and diversity of microbiota may be useful to developing a new paradigm in postharvest biocontrol that is based on constructing synthetic microbial communities that provide superior control of pathogens.