Fermented foods and beverages are a heterogeneous class of products with a relevant worldwide significance for human economy, nutrition and health for millennia. A huge diversity of microorganisms is associated with the enormous variety in terms of raw materials, fermentative behavior and obtained products. In this wide microbiodiversity it is possible that the presence of microbial pathogens and toxic by-products of microbial origin, including mycotoxins, ethyl carbamate and biogenic amines, are aspects liable to reduce the safety of the consumed product. Together with other approaches (e.g., use of preservatives, respect of specific physico-chemical parameters), starter cultures technology has been conceived to successfully dominate indigenous microflora and to drive fermentation to foresee the desired attributes of the matrix, assuring quality and safety. Recent trends indicate a general return to spontaneous food fermentation. In this review, we point out the potential risks for human health associated with uncontrolled (uninoculated) food fermentation and we discuss biotechnological approaches susceptible to conciliate fermented food safety, with instances of an enhanced contribution of microbes associated to spontaneous fermentation.

The sparkling wine market has expanded in recent years, boosted by the increasing demand of the global market. As for other fermented beverages, technological yeasts and bacteria selected to design commercial starter cultures represent key levers to maximize product quality and safety. The increasing economic interest in the sector of sparkling wine has also implied a renewed interest in microbial resource management. In this review, after a brief introduction, we report an overview of the main characterization criteria in order to select Saccharomyces cerevisiae strains suitable for use as starter cultures for the production of base wines and to drive re-fermentation of base wines to obtain sparkling wines. Particular attention has been reserved to the technological characterization aspects of re-fermenting phenotypes. We also analysed the possible uses of selected non-Saccharomyces and malolactic strains in order to differentiate specific productions. Finally, we highlighted the main safety aspects related to microbes of enological interest and underlined some microbial-based biotechnological applications helpful to pursue product and process innovations. Overall, the sparkling wine industry may find a relevant benefit from the exploitation of the wide resources associated with vineyard/wine microbial diversity.

Biocontrol strategies for the limitation of undesired microbial developments in foods and beverages represent a keystone toward the goal of more sustainable food systems. Brettanomyces bruxellensis is a wine spoilage microorganism that produces several compounds that are detrimental for the organoleptic quality of the wine, including some classes of volatile phenols. To control the proliferation of this yeast, sulfur dioxide is commonly employed, but the efficiency of this compound depends on the B. bruxellensis strain; and it is subject to wine composition and may induce the entrance in a viable, but nonculturable state of yeasts. Moreover, it can also elicit allergic reactions in humans. In recent years, biological alternatives to sulfur dioxide such as the use of yeasts and lactic acid bacteria starter cultures as biocontrol agents are being investigated. The controlled inoculation of starter cultures allows secure, fast and complete alcoholic and malolactic fermentations, limiting the residual nutrients that B. bruxellensis utilizes to survive and grow in wine. The current study is focused on the assessment of the effect of autochthonous yeasts and bacterial strains from the Apulia Region on the development of B. bruxellensis in wine, in terms of both growth and volatile phenols’ production. The investigation evidences the positive role of indigenous mixed cultures in the control of this spoilage yeast, either co-inoculating different strains of Saccharomyces cerevisiae, S. cerevisiae/non-Saccharomyces or co-inoculating S. cerevisiae/Oenococcus oeni. Our findings expand the existing knowledge of the application of protechnological microbial diversity and of non-Saccharomyces as a biocontrol agent in oenology. We report a further demonstration of the interest in selecting indigenous strains as a strategic tool for winemakers interested in the improvement of regional wines.

For three consecutive years, an Italian winery in Apulia has dealt with sudden alcoholic stuck fermentation in the early stages of vinification process, i.e., typical defects addressable to bacterial spoilage. After a prescreening trial, we assessed, for the first time, the influence of the commercial fungicide preparation Ridomil Gold^® (Combi Pepite), containing Metalaxyl-M (4.85%) and Folpet (40%) as active principles, on the growth of several yeasts (Saccharomyces cerevisiae and non-Saccharomyces spp.) and lactic acid bacteria of oenological interest. We also tested, separately and in combination, the effects of Metalaxyl-M and Folpet molecules on microbial growth both in culture media and in grape must. We recalled the attention on Folpet negative effect on yeasts, extending its inhibitory spectrum on non-Saccharomyces (e.g., Candida spp.). Moreover, we highlighted a synergic effect of Metalaxyl-M and Folpet used together and a possible inhibitory role of the fungicide excipients. Interestingly, we identified the autochthonous S. cerevisiae strain E4 as moderately resistant to the Folpet toxicity. Our findings clearly indicate the urgent need for integrating the screening procedures for admission of pesticides for use on wine grape with trials testing their effects on the physiology of protechnological microbes.