A phenomenological model to infer the microbial growth: A case study for psychrotrophic pathogenic bacteria.

AIMS: The two-parameter (α and ß) Schiraldi's model reliably fits growth curves of psychrotrophic pathogens and suggests a different description of the latency phase. METHODS AND RESULTS: Data obtained at various temperatures and different starting cell densities for Aeromonas hydrophila, Listeria monocytogenes and Yersinia enterocolitica have been fitted with the Baranyi and Roberts' model and the new one. On average, the former showed higher standard error and R2 values (0.140 and 0.991) than the Schiraldi's one (0.079 and 0.983). Around 15℃, the increase of temperature showed a milder effect on the growth rate than that expected. Y. enterocolitica showed a practically null duration of the lag phase, no matter the value of the starting density, whereas A. hydrophila and L. monocytogenes revealed slower onset trends. CONCLUSIONS: Parameter ß defines the number of cell duplications and appears independent on temperature, while (ß/α)1/2 is proportional to the maximum specific growth rate. The α-1/2 versus temperature trend directly reflects the corresponding behaviour of the growth rate and does not require the use of Arrhenius plots. SIGNIFICANCE AND IMPACT OF THE STUDY: Values of the parameters α and ß, as well as the duration of the latency phase, allowed some considerations about the effect of storage temperature in terms of food safety, especially for psychrotrophic bacteria of concern.

Investigating the growth kinetics in sourdough microbial associations.

In this study we investigated the effect of the single strain in stabilization of type I sourdough microbial associations by crossing six different Fructilactobacillus sanfranciscensis with five Kazachstania humilis strains. Furthermore, we compared three predictive models, Zwitwering based on Gompertz's equation, Baranyi and Roberts' function and Schiraldi's function to evaluate which one best fitted the experimental data in determining the behaviour of co-cultivated microorganisms. Specific growth rates (µm) and lag time (λ) values for each mixed population were assessed. Results showed that the different F. sanfranciscensis strains significantly steer the growth kinetics within the pair and affect the ratio bacterial/yeast cells, as data analysis confirmed, whereas K. humilis accommodates to the bacterial strain. To compare the growth models, Root Mean Square (RMS) values were calculated for each predicted curve by implementing an algorithm based on an iterative process to minimize the deviation among observed and calculated data. Schiraldi's function performed better than the others, revealing, on average, the smallest RMS values and providing the best fitting for over 70% of co-cultivation experiments. Models prove to be consistent in predicting growth kinetics of microbial consortia too.

Tryptophan Derivatives by Saccharomyces cerevisiae EC1118: Evaluation, Optimization, and Production in a Soybean-Based Medium.

Given the pharmacological properti es and the potential role of kynurenic acid (KYNA) in human physiology and the pleiotropic activity of the neurohormone melatonin (MEL) involved in physiological and immunological functions and as regulator of antioxidant enzymes, this study aimed at evaluating the capability of Saccharomyces cerevisiae EC1118 to release tryptophan derivatives (dTRPs) from the kynurenine (KYN) and melatonin pathways. The setting up of the spectroscopic and chromatographic conditions for the quantification of the dTRPs in LC-MS/MS system, the optimization of dTRPs' production in fermentative and whole-cell biotransformation approaches and the production of dTRPs in a soybean-based cultural medium naturally enriched in tryptophan, as a case of study, were included in the experimental plan. Variable amounts of dTRPs, with a prevalence of metabolites of the KYN pathway, were detected. The LC-MS/MS analysis showed that the compound synthesized at highest concentration is KYNA that reached 9.146 ± 0.585 mg/L in fermentation trials in a chemically defined medium at 400 mg/L TRP. Further experiments in a soybean-based medium confirm KYNA as the main dTRPs, whereas the other dTRPs reached very lower concentrations. While detectable quantities of melatonin were never observed, two MEL isomers were successfully measured in laboratory media.

Transcriptomics unravels the adaptive molecular mechanisms of Brettanomyces bruxellensis under SO2 stress in wine condition.

Sulfur dioxide is generally used as an antimicrobial in wine to counteract the activity of spoilage yeasts, including Brettanomyces bruxellensis. However, this chemical does not exert the same effectiveness on different B. bruxellensis yeasts since some strains can proliferate in the final product leading to a negative sensory profile due to 4-ethylguaiacol and 4-ethylphenol. Thus, the capability of deciphering the general molecular mechanisms characterizing this yeast species' response in presence of SO2 stress could be considered strategic for a better management of SO2 in winemaking. A RNA-Seq approach was used to investigate the gene expression of two strains of B. bruxellensis, AWRI 1499 and CBS 2499 having different genetic backgrounds, when exposed to a SO2 pulse. Results revealed that sulphites affected yeast culturability and metabolism, but not volatile phenol production suggesting that a phenotypical heterogeneity could be involved for the SO2 cell adaptation. The transcriptomics variation in response to SO2 stress confirmed the strain-related response in B. bruxellensis and the GO analysis of common differentially expressed genes showed that the detoxification process carried out by SSU1 gene can be considered as the principal specific adaptive response to counteract the SO2 presence. However, nonspecific mechanisms can be exploited by cells to assist the SO2 tolerance; namely, the metabolisms related to sugar alcohol (polyols) and oxidative stress, and structural compounds.

Production of melatonin and other tryptophan derivatives by Oenococcus oeni under winery and laboratory scale.

Malolactic fermentation (MLF) in Valtellina Superiore DOCG red wine was monitored in 4 cellars and the final products were analysed to determine the content of melatonin (MEL) and other tryptophan (TRP) derivatives, including tryptophan ethyl ester (TEE) and MEL isomers (MISs), and to isolate predominant O. oeni strains. MEL and TEE significantly increased in wines after MLF from two cellars out of four. Six strains were isolated during the MLF of red wines and under laboratory scale, in rich and synthetic wine cultural media, together with other four O. oeni strains able to trigger the MLF. Results showed that the presence of stressful growth factors, like ethanol and acid pH, has a pivotal role in triggering the release of TEE by oenococci. Indeed, all the strains became capable to produce also MEL and MISs, together with TEE. under harsh growth conditions, as in a synthetic wine medium. The production of these compounds was strain-dependent and a maximum amount of 0.0078 ±â€¯0.0023 ngT/mL (UMB472) and 619.85 ±â€¯196.16 ngT/mL (UMB436) of MEL and TEE was obtained, respectively. In particular, different MISs were detected under oenological and laboratory scale suggesting that other factors (i.e. technological and/or physico-chemical) could affect the synthesis of TRP derivatives.

LC-MS/MS-Based Profiling of Tryptophan-Related Metabolites in Healthy Plant Foods.

Food plants contain hundreds of bioactive phytochemicals arising from different secondary metabolic pathways. Among these, the metabolic route of the amino acid Tryptophan yields a large number of plant natural products with chemically and pharmacologically diverse properties. We propose the identifier "indolome" to collect all metabolites in the Tryptophan pathway. In addition, Tryptophan-rich plant sources can be used as substrates for the fermentation by yeast strains to produce pharmacologically active metabolites, such as Melatonin. To pursue this technological development, we have developed a UHPLC-MS/MS method to monitor 14 Tryptophan, Tryptamine, amino-benzoic, and pyridine metabolites. In addition, different extraction procedures to improve the recovery of Tryptophan and its derivatives from the vegetal matrix were tested. We investigated soybeans, pumpkin seeds, sesame seeds, and spirulina because of their botanical diversity and documented healthy effects. Four different extractions with different solvents and temperatures were tested, and water extraction at room temperature was chosen as the most suitable procedure to extract the whole Tryptophan metabolites pattern (called by us "indolome") in terms of ease, high efficiency, short time, low cost, and sustainability. In all plant matrices, Tryptophan was the most abundant indole compound, while the pattern of its metabolites was different in the diverse plants extracts. Overall, 5-OH Tryptamine and Kynurenine were the most abundant compounds, despite being 100-1000-fold lower than Tryptophan. Melatonin was undetected in all extracts, but sesame showed the presence of a Melatonin isomer. The results of this study highlight the variability in the occurrence of indole compounds among diverse food plants. The knowledge of Tryptophan metabolism in plants represents a relevant issue for human health and nutrition.

Cloning the putative gene of vinyl phenol reductase of Dekkera bruxellensis in Saccharomyces cerevisiae.

Vinylphenol reductase of Dekkera bruxellensis, the characteristic enzyme liable for "Brett" sensory modification of wine, has been recently recognized to belong to the short chain dehydrogenases/reductases family. Indeed, a preliminary biochemical characterisation has conferred to the purified protein a dual significance acting as superoxide dismutase and as a NADH-dependent reductase. The present study aimed for providing a certain identification of the enzyme by cloning the VPR gene in S. cerevisiae, a species not producing ethyl phenols. Transformed clones of S. cerevisiae resulted capable of expressing a biologically active form of the heterologous protein, proving its role in the conversion of 4-vinyl guaiacol to 4-ethyl guaiacol. A VPR specific protein activity of 9 ± 0.6 mU/mg was found in crude extracts of S. cerevisiae recombinant strain. This result was confirmed in activity trials carried out with the protein purified from transformant cells of S. cerevisiae by a his-tag purification approach; in particular, VPR-enriched fractions showed a specific activity of 1.83 ± 0.03 U/mg at pH 6.0. Furthermore, in agreement with literature, the purified protein behaves like a SOD, with a calculated specific activity of approximatively 3.41 U/mg. The comparative genetic analysis of the partial VPR gene sequences from 17 different D. bruxellesis strains suggested that the observed polymorphism (2.3%) and the allelic heterozygosity state of the gene do not justify the well described strain-dependent character in producing volatile phenols of this species. Actually, no correlation exists between genotype membership of the analysed strains and their capability to release off-flavours. This work adds valuable knowledge to the study of D. bruxellensis wine spoilage and prepare the ground for interesting future industrial applications.

The vintage effect overcomes the terroir effect: a three year survey on the wine yeast biodiversity in Franciacorta and Oltrepò Pavese, two northern Italian vine-growing areas.

A three year survey on the dominant yeast populations in samples of air, must and wine in different vineyards and cellars of two northern Italian vine-growing territories (six sites in Franciacorta and eight sites in Oltrepò Pavese areas) was carried out. A total of 505 isolates were ascribed to 31 different species by RFLP analysis of the ITS1-5.8SrRNA-ITS2 region and partial sequence analysis of the 26S rRNA gene. The most commonly found species were Saccharomyces cerevisiae (frequency, F' = 58.7%; incidence, I' = 53.5%), Hanseniaspora uvarum (F' = 14.3%; I' = 5.3%), Metschnikowia fructicola (F' = 11.1%; I' = 5.0%) and Torulaspora delbrueckii (F' = 10.3%; I' = 3.8%). Among 270 S. cerevisiae new isolates, 156 (57.8%) revealed a different genetic pattern through polymorphism analysis of the interdelta regions by capillary electrophoresis, while 47 isolates (17.4 %) were clones of starter cultures. By considering the Shannon-Wiener index and results of principal component analysis (PCA) analyses, the year of isolation (vintage) proved to be a factor that significantly affected the biodiversity of the yeast species, whereas the geographical site (terroir) was not. Seventy-five per cent of S. cerevisiae isolates gathered in a unique cluster at a similarity level of 82%, while the remaining 25% were separated into minor groups without any evident relationship between δ-PCR profile and territory, year or source of isolation. However, in six cases a similar strain appeared at the harvesting time both in Franciacorta and Oltrepò Pavese areas, whereas surprisingly no strain was reisolated in the same vineyard or cellar for consecutive years.

Yeast contribution to melatonin, melatonin isomers and tryptophan ethyl ester during alcoholic fermentation of grape musts.

Melatonin (MEL) has been found in some medicinal and food plants, including grapevine, a commodity of particular interest for the production of wine, a beverage of economic relevance. It has also been suggested that MEL in wine may, at least in part, contribute to the health-promoting properties attributed to this beverage and, possibly, to other traditional Mediterranean foodstuffs. After a preliminary screening of 9 yeast strains in laboratory medium, three selected strains (Saccharomyces cerevisiae EC1118, Torulaspora delbrueckii CBS1146(T) and Zygosaccharomyces bailii ATCC36947(T) ) were inoculated in experimental musts obtained from 2 white (Moscato and Chardonnay) and 2 red (Croatina and Merlot) grape varieties. The production of MEL, melatonin isomers (MIs) and tryptophan ethyl ester (TEE) was monitored during the alcoholic fermentation. The screening showed that the three investigated strains produced the highest concentrations of MEL and two MIs in optimal growth conditions. However, MEL and MIs were not produced in oenological conditions, but the three strains synthesized high concentrations of a new MI and TEE in musts.

Cold exposure affects carbohydrates and lipid metabolism, and induces Hog1p phosphorylation in Dekkera bruxellensis strain CBS 2499.

Dekkera bruxellensis is a yeast known to affect the quality of wine and beer. This species, due to its high ethanol and acid tolerance, has been reported also to compete with Saccharomyces cerevisiae in distilleries producing fuel ethanol. In order to understand how this species responds when exposed to low temperatures, some mechanisms like synthesis and accumulation of intracellular metabolites, changes in lipid composition and activation of the HOG-MAPK pathway were investigated in the genome sequenced strain CBS 2499. We show that cold stress caused intracellular accumulation of glycogen, but did not induce accumulation of trehalose and glycerol. The cellular fatty acid composition changed after the temperature downshift, and a significant increase of palmitoleic acid was observed. RT-PCR analysis revealed that OLE1 encoding for Δ9-fatty acid desaturase was up-regulated, whereas TPS1 and INO1 didn't show changes in their expression. In D. bruxellensis Hog1p was activated by phosphorylation, as described in S. cerevisiae, highlighting a conserved role of the HOG-MAP kinase signaling pathway in cold stress response.

Candida milleri species reveals intraspecific genetic and metabolic polymorphisms.

Candida milleri, together with Candida humilis, is the most representative yeast species found in type I sourdough ecosystems. In this work, comparison of the ITS region and the D1/D2 domain of 26S rDNA gene partial sequences, karyotyping, mtDNA-RFLP analysis, Intron Splice Site dispersion (ISS-PCR) and (GTG)5 microsatellite analyses, assimilation test of different carbohydrates, and metabolome assessment by FT-IR analysis, were investigated in seventeen strains isolated from four different companies as well as in type strains CBS6897(T) and CBS5658(T). Most isolates were ascribed to C. milleri, even if a strong relatedness was confirmed with C. humilis as well, particularly for three strains. Genetic characterization showed a high degree of intraspecific polymorphism since 12 different genotypes were discriminated. The number of chromosomes varied from 9 to 13 and their size ranged from less than 0.3 to over 2 Mbp. Phenotypic traits let to recognize 9 different profiles of carbon sources assimilation. FT-IR spectra from yeast cells cultivated in different media and collected at different growth phases revealed a diversity of behaviour among strains in accordance with the results of PCR-based fingerprinting. A clear evidence of the polymorphic status of C. milleri species is provided thus representing an important feature for the development of technological applications in bakery industries.

Assessment of the Brettanomyces bruxellensis metabolome during sulphur dioxide exposure.

Brettanomyces bruxellensis displays a high degree of genotypic and phenotypic polymorphism and is the main yeast species involved in wine spoilage. The innate resistance of 108 B. bruxellensis strains to the antimicrobial agent SO2 used in winemaking was investigated. Nineteen strains (17.6%) were sensitive to SO2 , failing to grow at the lowest concentration tested (0.1 mg L(-1) molecular SO2). Twenty-nine strains (26.8%) grew at 0.1 mg L(-1), 42 strains (38.9%) grew at 0.2 mg L(-1) , and 16 strains (14.8%) were able to grow as high as 0.4 mg L(-1) mol. SO2. Two strains able to grow in the presence of 0.6 mg L(-1) mol. SO2 were further studied by GCMS-TOF analysis to define the metabolic response to SO2 treatment. Two hundred and fifty-three intracellular metabolites were detected. The main effect observed was a decrease in cytoplasmic levels of polyols and an increase in levels of some amino acids, alanine, glutamic acid, glycine, proline, 5-oxoproline, serine and valine, which were significantly accumulated in the presence of SO2. No alteration in the pentose phosphate pathway was observed, suggesting NADPH usage could be diverted to other pathways. Finally, a change in metabolites involved in the glycerophospholipid pathway (glycerol-3-phosphate and myo-inositol) was also found.

Shaping Future Foods through Fermentation of Side Streams: Microbial, Chemical, and Physical Characteristics of Fermented Blends from Sunflower Seed Press Cake and Cheese Whey.

The current food system suffers from the inefficient use of resources, including the generation of side streams of low economic value that still contain nutritional components. One potential approach to reach a more sustainable food system is to reintroduce such side streams into a circular value chain and valorise them in novel food products, preferably in an unrefined or minimally refined manner. Blending side streams from different industries might be a suitable way to improve the nutritional value of the final matrix. In this study, sunflower seed press cake and cheese whey were combined to obtain matrices containing valuable proteins, structuring polysaccharides, as well as lactose and minerals facilitating fermentation with three different co-cultures of lactic acid bacteria and yeasts. Fermentation for 48 h at 26 °C decreased the pH from ~6.3 to ~4.7 and enhanced the storage stability of the blends with no effect on their rheological properties and microstructure. This research demonstrates the potential of fermentation as a mean to stabilise side stream blends while only minimally affecting their physical appearance.

The Riboflavin Metabolism in Four Saccharomyces cerevisiae Wine Strains: Assessment in Oenological Condition and Potential Implications with the Light-Struck Taste.

Riboflavin (RF), or vitamin B2, is an essential compound for yeast growth and a precursor of the flavin coenzymes, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), involved in redox and non-redox processes. RF is a photosensitive compound involved in the light-struck taste (LST), a fault causing the formation of off-flavors that can develop when the wine is exposed to light in the presence of methionine (Met), as well. As both RF and Met can be associated with detrimental changes in wines, a better comprehension of its yeast-mediated production is relevant to predict the maintenance of the desired character of the wine. This study aims at assessing the production of flavin derivatives (FDs) and Met by S. cerevisiae oenological starters under laboratory conditions. The results showed the presence of extra- and intracellular FDs, and Met is a strain-dependent characteristic being also affected by the initial content of RF in the medium. This finding was confirmed when the winemaking was carried out in a relevant environment. Our results evidenced the important impact of the yeast strain on the content of RF and its derivatives.

Valorisation of Bovine Sweet Whey and Sunflower Press Cake Blend through Controlled Fermentation as Platform for Innovative Food Materials.

The current environmental challenge is pushing food systems towards more sustainable models of production that require reorganizing of processes by re-using side products still containing nutrients. This work aimed at valorising a mix of bovine sweet whey and sunflower press cake, through targeted fermentation. After preliminary screening based on growth rate, final pH, lactose/galactose assimilation, phytase activity, six Lactic Acid Bacteria strains (Lacticaseibacillus casei, L. paracasei (2), Lactococcus lactis, Lentilactobacillus parakefiri and Leuconostoc pseudomesenteroides) and three yeasts (Kluyveromyces lactis, K. marxianus and Torulaspora delbrueckii) were co-cultivated in pairs in microcosms (1-part ground press cake: 4-parts whey). All tested microorganisms were able to grow and acidify the blend: the LAB counts increased during the incubation (26 °C for 48 h) of +2.80 log CFU/g, whereas yeasts counts were of +1.98 log CFU/g, with significant differences among the different associations (p < 0.01). Mould counts were always <3 log CFU/g. Interestingly, the bacterial contaminants count significantly varied in samples with different pairs of strains (p < 0.001). Acidification level, acetic acid and ethanol contents were the limiting factors affecting the growth of spoilage micro-organisms. Best performances were attained in microcosms inoculated with L. lactis or L. paracasei and K. lactis or K. marxianus.

Culturable Yeast Diversity of Grape Berries from Vitis vinifera ssp. sylvestris (Gmelin) Hegi.

Vitis vinifera L. ssp. sylvestris (Gmelin) Hegi is recognized as the dioecious parental generation of today's cultivars. Climatic change and the arrival of pathogens and pests in Europe led it to be included on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species in 1997. The present work focused on the study of culturable yeast occurrence and diversity of grape berries collected from wild vines. Sampling was performed in 29 locations of Azerbaijan, Georgia, Italy, Romania, and Spain. In total, 3431 yeast colonies were isolated and identified as belonging to 49 species, including Saccharomyces cerevisiae, by 26S rDNA D1/D2 domains and ITS region sequencing. Isolates of S. cerevisiae were also analyzed by SSR-PCR obtaining 185 different genotypes. Classical ecology indices were used to obtain the richness (S), the biodiversity (H'), and the dominance (D) of the species studied. This study highlights the biodiversity potential of natural environments that still represent a fascinating source of solutions to common problems in winemaking.

Identifying the Main Drivers in Microbial Diversity for Cabernet Sauvignon Cultivars from Europe to South Africa: Evidence for a Cultivar-Specific Microbial Fingerprint.

Microbial diversity in vineyards and in grapes has generated significant scientific interest. From a biotechnological perspective, vineyard and grape biodiversity has been shown to impact soil, vine, and grape health and to determine the fermentation microbiome and the final character of wine. Thus, an understanding of the drivers that are responsible for the differences in vineyard and grape microbiota is required. The impact of soil and climate, as well as of viticultural practices in geographically delimited areas, have been reported. However, the limited scale makes the identification of generally applicable drivers of microbial biodiversity and of specific microbial fingerprints challenging. The comparison and meta-analysis of different datasets is furthermore complicated by differences in sampling and in methodology. Here we present data from a wide-ranging coordinated approach, using standardized sampling and data generation and analysis, involving four countries with different climates and viticultural traditions. The data confirm the existence of a grape core microbial consortium, but also provide evidence for country-specific microbiota and suggest the existence of a cultivar-specific microbial fingerprint for Cabernet Sauvignon grape. This study puts in evidence new insight of the grape microbial community in two continents and the importance of both location and cultivar for the definition of the grape microbiome.

Validation of a Standard Protocol to Assess the Fermentative and Chemical Properties of Saccharomyces cerevisiae Wine Strains.

This paper reports on a common experiment performed by 17 Research Units of the Italian Group of Microbiology of Vine and Wine (GMVV), which belongs to the Scientific Society SIMTREA, with the aim to validate a protocol for the characterization of wine strains of Saccharomyces cerevisiae. For this purpose, two commercial S. cerevisiae strains (EC 1118 and AWRI796) were used to carry out inter-laboratory-scale comparative fermentations using both synthetic medium and grape musts and applying the same protocol to obtain reproducible, replicable, and statistically valid results. Ethanol yield, production of acetic acid, glycerol, higher alcohols, and other volatile compounds were assessed. Moreover, the Fourier transform infrared spectroscopy was also applied to define the metabolomic fingerprint of yeast cells from each experimental trial. Data were standardized as unit of compounds or yield per gram of sugar (glucose and fructose) consumed throughout fermentation, and analyzed through parametric and non-parametric tests, and multivariate approaches (cluster analysis, two-way joining, and principal component analysis). The results of experiments carried out by using synthetic must showed that it was possible to gain comparable results from three different laboratories by using the same strains. Then, the use of the standardized protocol on different grape musts allowed pointing out the goodness and the reproducibility of the method; it showed the main traits of the two yeast strains and allowed reducing variability amongst independent batches (biological replicates) to acceptable levels. In conclusion, the findings of this collaborative study contributed to the validation of a protocol in a specific synthetic medium and in grape must and showed how data should be treated to gain reproducible and robust results, which could allow direct comparison of the experimental data obtained during the characterization of wine yeasts carried out by different research laboratories.

Application of Bacteriophages on Shiga Toxin-Producing Escherichia coli (STEC) Biofilm.

Shiga toxin-producing Escherichia coli are pathogenic bacteria able to form biofilms both on abiotic surfaces and on food, thus increasing risks for food consumers. Moreover, biofilms are difficult to remove and more resistant to antimicrobial agents compared to planktonic cells. Bacteriophages, natural predators of bacteria, can be used as an alternative to prevent biofilm formation or to remove pre-formed biofilm. In this work, four STEC able to produce biofilm were selected among 31 different strains and tested against single bacteriophages and two-phage cocktails. Results showed that our phages were able to reduce biofilm formation by 43.46% both when used as single phage preparation and as a cocktail formulation. Since one of the two cocktails had a slightly better performance, it was used to remove pre-existing biofilms. In this case, the phages were unable to destroy the biofilms and reduce the number of bacterial cells. Our data confirm that preventing biofilm formation in a food plant is better than trying to remove a preformed biofilm and the continuous presence of bacteriophages in the process environment could reduce the number of bacteria able to form biofilms and therefore improve the food safety.

The Role of Yeasts as Biocontrol Agents for Pathogenic Fungi on Postharvest Grapes: A Review.

In view of the growing concern about the impact of synthetic fungicides on human health and the environment, several government bodies have decided to ban them. As a result, a great number of studies have been carried out in recent decades with the aim of finding a biological alternative to inhibit the growth of fungal pathogens. In order to avoid the large losses of fruit and vegetables that these pathogens cause every year, the biological alternative's efficacy should be the same as that of a chemical pesticide. In this review, the main studies discussed concern Saccharomyces and non-Saccharomyces yeasts as potential antagonists against phytopathogenic fungi of the genera Penicillium and Aspergillus and the species Botrytis cinerea on table grapes, wine grapes, and raisins.