Patagonian Antagonist Yeasts for Food Biopreservation

Abstract

Worldwide, microbial growth destroys large amounts of various products, causing yield losses in the agronomical and biotechnological industries. Traditionally, biocides have been used to manage these problems, but different disadvantages such as the establishment of resistant strains and the suppression of natural competitors have made alternatives such as biological control necessary. After harvest, many fruits are kept in cold storage to prolong their availability and shelf life. Often, this requires the application of a chemical fungicide to prevent postharvest decay from decay fungi. An alternative approach for preventing postharvest fungal decay during storage could be based on the treatment of the commodity with antagonistic yeasts. In this regard, the use of cold­adapted yeasts may offer a distinct advantage. Numerous cold­adapted yeasts species have been isolated from artificial cold environments, as well as cold­stored fruits. Recently, we isolated and identified epiphytic yeasts during the cold postharvest storage of pears and fine fruits from packinghouses in Argentinean Patagonia, and we tested their efficacy in controlling the Postharvest diseases of different fruits caused by several pathogens. Additionally, killer yeasts as producers of mycocins or killer toxins that can neutralize the activities of spoilage yeasts in wines represent an interesting biocontrol strategy.Several screening studies focused to determine the occurrence of killer yeasts in winemaking environments have been carried out, and they have demonstrated the presence of killer phenotypes in yeasts from wines, cellar surfaces, and winery equipment. In previous studies carried out in our laboratory, most yeasts isolated from spontaneously fermenting grape musts evidenced killer character. These studies provide an exceptional source of potential antagonist yeasts to be used in biocontrol of undesired microorganisms in wine.Nonetheless, it is necessary to continue to identify new potential microorganisms and to develop a better understanding of the biology of yeast biocontrol systems to increase the potential of postharvest biocontrol as a viable alternative to synthetic postharvest fungicides and chemical Preservatives against wine spoilage yeast.