Aspergillus flavus is a toxigenic fungal colonizer of fruits and cereals and may produce one of the most important mycotoxins from a food safety perspective, aflatoxins. Therefore, its growth and mycotoxin production should be effectively avoided to protect consumers’ health. Among the safe and green antifungal strategies that can be applied in the field, biocontrol is a recent and emerging strategy that needs to be explored. Yeasts are normally good biocontrol candidates to minimize mold-related hazards and their modes of action are numerous, one of them being the production of volatile organic compounds (VOCs). To this end, the influence of VOCs produced by Hanseniaspora opuntiae L479 and Hanseniaspora uvarum L793 on growth, expression of the regulatory gene of the aflatoxin pathway (aflR) and mycotoxin production by A. flavus for 21 days was assessed. The results showed that both yeasts, despite producing different kinds of VOCs, had a similar effect on inhibiting growth, mycotoxin biosynthetic gene expression and phenotypic toxin production overall at the mid-incubation period when their synthesis was the greatest. Based on the results, both yeast strains, H. opuntiae L479 and H. uvarum L793, are potentially suitable as a biopreservative agents for inhibiting the growth of A. flavus and reducing aflatoxin accumulation.

Biocontrol is one of the most promising alternatives to synthetic fungicides for food preservation. Botrytis cinerea, Alternaria alternata, and Aspergillus section Nigri are the most concerning pathogens for grape development. However, frequently, other species, such as Penicillium glabrum in this study, are predominant in spoiled bunches. In this work, 54 native yeasts from vineyards were screened by direct confrontation in potato dextrose agar plates as antagonists against P. glabrum. Isolates of Pichia terricola, Aureobasidium pullulans, and Zygoascus meyerae were selected for their antagonist activity in vitro, plus isolates of Pichia kudriavzevii, Hormonema viticola, and Hanseniaspora uvarum were used as negative controls. However, in vivo, confrontations in wounded grapes showed disagreement with direct confrontation in vitro. P. terricola, P. kudriavzevii, H. viticola, Z. meyerae, and H. uvarum significantly reduced the incidence of P. glabrum on grapes. Nevertheless, P. terricola, H. viticola, and H. uvarum themselves spoiled the wounded grapes. Inhibitions were associated with different mechanisms such as the production of volatile organic compounds (VOCs), lytic enzymes, biofilm formation, and competition for nutrients. The isolates of P. kudriavzevii L18 (a producer of antifungal VOCs which completely inhibited the incidence of P. glabrum) and Z. meyerae L29 (with pectinase, chitinase and β-glucanase activity and biofilm formation which reduced 70% of the incidence of P. glabrum) are proposed as suitable biocontrol agents against P. glabrum.

The pre and postharvest disease named ‘aqueous spot’ is an emerging risk for sweet cherries growing in Jerte Valley (Cáceres, Spain). Early stages of the disease appear in the tree, but it is usually detected after harvesting, during the postharvest period. Symptoms include the appearance of skin discolouration and translucency in the shoulder areas. At the most advanced stages, a mycelium of white colour partially or completely covers the fruit. This manuscript provides a detailed description of the microbes involved in this disease, such as bacteria, yeasts, and moulds. Microbes of different cherry cultivars were studied during two consecutive seasons (2019 and 2020). The counts of bacteria and yeast in damaged tissues were higher (7.05 and 6.38 log10 CFU/g for total aerobic mesophilic microbes and yeasts, respectively) than sound tissues (6.08 and 5.19 log10 CFU/g, respectively). The Enterobacterales order dominated the bacteria population. Among yeasts, Yarrowia lipolytica, in 2019, and Metschnikowia pulcherrima and Metschnikowia viticola, in 2020, were consistently isolated from all samples. The presence of moulds was inconsistently detected at the early stage of this disease by plate counts. However, microscopic observations revealed the presence of hyphae in cherry flesh. Different pathogenic moulds were identified, although white mycelium, identified as Botrytis cinerea by molecular methods, was consistently isolated at later stages. Inoculation tests confirmed the involvement of white-mycelium B. cinerea in the development of this new postharvest disease in the Jerte Valley. Its combination with Enterobacterales enhanced the evolution of rotting, whereas the combination with yeasts decreased and delayed the symptoms. This work presents the first report of a consortia of microorganisms implicated in the development of ‘aqueous spot’, an emerging disease in sweet cherry cultivars in the Jerte Valley.

BACKGROUND: Stone fruits are vulnerable to contamination by Penicillium expansum (PE), a patulin‐producing mould. The use of yeasts as biocontrol agents could be an effective strategy to combat this pathogen. This study evaluated the ability of Metschnikowia pulcherrima L672 (L672) and Pichia kudriavzevii L40 (L40) as biocontrol strategies on peach ( Romea ), black plum ( Black gold ), nectarine ( Nectavista ), and flat peach ( Flat Beauty ), analysing their impact on incidence and severity of PE damage, patulin production and the expression of the idh gene, a key gene of the patulin biosynthetic pathway. RESULTS: The results indicate that both yeasts reduced the incidence and severity of PE in the four stone fruit types studied, with a more pronounced effect observed for L672. This yeast reduced the presence of patulin in three of the stone fruits where patulin was produced by PE (nectarine, peach and black plum), while P. kudriavzevii L40 limited patulin production in peach by 90%. Regarding the study of the expression of the idh gene, L40 increased its expression compared to the control, although this effect varied among fruits. In contrast, L672 did not produce changes in gene expression in nectarines and black plums – fruits where patulin was not detected. CONCLUSION: The application of the yeasts L672 and L40 as biocontrol agents was shown to be an effective strategy to reduce the incidence and severity of PE and patulin production in stone fruits, with a greater effect of L672 in most cases. Furthermore, differences were observed in the regulation of the idh gene, suggesting that the efficacy of biocontrol in this aspect depends on both the yeast used and the type of fruit. © 2025 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

This study investigated the seasonal and spatial dynamics of off-flavour compounds—geosmin and 2-methylisoborneol (2-MIB)—in an intensive rainbow trout (Oncorhynchus mykiss) aquaculture system for human consumption in western Spain. Weekly water and fish flesh samples were collected over a 12-month period from three farms supplied by the River Tormes. Physicochemical parameters, determination of geosmin and 2-MIB by SPME-GC-MS, microbial counts, and microbial community composition were assessed alongside volatile compound concentrations. Geosmin and 2-MIB showed marked seasonal variation, with peak levels in water and fish flesh during spring and summer, correlating positively with temperature. Geosmin accumulation in fish was highest in the downstream farm, suggesting cumulative exposure effects. In contrast, 2-MIB was detected only in water and at lower concentrations. Microbial analyses revealed high bacterial and fungal diversity, including cyanobacterial taxa such as Phormidium setchellianum and Pseudoanabaena minima, known producers of geosmin and 2-MIB. These findings highlight the importance of water microbiota and environmental conditions in off-flavour development. Managing cyanobacterial populations and monitoring spatial-temporal variability are essential to mitigate the development of earthy or musty flavours and economic losses in aquaculture systems.

Using beneficial microorganisms along with sustainable strategies such as agronomic biofortification offers eco-friendly alternatives to combat climate change in ecosystems like dehesas. This study analyzes the combined effects of four wild Trichoderma spp. isolated from Extremadura, Spain (T. koningiopsis, two T. gamsii, and T. koningii, with negative and positive controls) and four Zn biofortification treatments (no Zn application; soil application of 5 mg of ZnSO₄·7H₂O per kg of soil, labeled soil Zn; two foliar applications of 5 mL 0.5% ZnSO₄·7H₂O, labeled foliar Zn; and soil + foliar combination, labeled SF) on Trifolium subterraneum performance. The combination of T. koningiopsis and T. gamsii with foliar Zn improved plant growth by up to 34.4%. Zinc accumulation was about 30% higher when T. gamsii and T. koningii were applied with SF, and their inoculation resulted in a 2.5-fold increase in ash. Trichoderma spp. affected nodulation differently; both T. gamsii inhibited nodulation by 24%, whereas neither T. koningiopsis nor T. koningii showed differences from the controls. These results highlight the potential of combining beneficial microorganisms with biofortification strategies to address nutrient deficiencies and improve agricultural sustainability. However, the complex interactions between both factors underscore the importance of strain selection and call for further research to optimize application strategies and elucidate underlying mechanisms.