Browsing by Author "Schorr-Galindo, Sabine"

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    Biocontrol activities of yeasts or lactic acid bacteria isolated from Robusta coffee against Aspergillus carbonarius growth and ochratoxin A production in vitro
    (Elsevier, 2024-04-16) López Rodríguez, Claudia; Strub, Caroline; Fontana, Angélique; Verheecke-Vaessen, Carol; Durand, Noël; Beugré, Corinne; Guehi, Tagro; Medina, Angel; Schorr-Galindo, Sabine
    Biocontrol Agents (BCAs) can be an eco-friendly alternative to fungicides to reduce the contamination with mycotoxigenic fungi on coffee. In the present study, different strains of bacteria and yeasts were isolated from Ivorian Robusta coffee. Their ability to reduce fungal growth and Ochratoxin A (OTA) production during their confrontation against Aspergillus carbonarius was screened on solid media. Some strains were able to reduce growth and OTA production by 85 % and 90 % and were molecularly identified as two yeasts, Rhodosporidiobolus ruineniae and Meyerozyma caribbica. Subsequent tests on liquid media with A. carbonarius or solely with OTA revealed adhesion of R. ruineniae to the mycelium of A. carbonarius through Scanning Electron Microscopy, and an OTA adsorption efficiency of 50 %. For M. caribbica potential degradation of OTA after 24 h incubation was observed. Both yeasts could be potential BCAs good candidates for Ivorian Robusta coffee protection against A. carbonarius and OTA contamination.
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    Biocontrol of ochratoxigenic fungi by endogenous lactic acid bacteria and yeasts from ivorian robusta coffee in the context of climate change
    (Cranfield University, 2023-09) López Rodríguez, Claudia; Medina, Angel; Schorr-Galindo, Sabine; Verheecke-Vaessen, Carol; Fontana, Angelique; Strub, Caroline
    This doctoral research delves into the innovative domain of biocontrol strategies targeting mycotoxigenic fungi in the context of climate change. Focusing on Ivorian coffee, a vital economic and agricultural commodity, the study explores the potential of indigenous lactic acid bacteria (LAB) and yeasts as biocontrol agents. Mycotoxins, toxic secondary metabolites produced by fungi, pose significant health risks and economic losses. As climate change amplifies the proliferation of mycotoxigenic fungi, the demand for sustainable and eco-friendly interventions intensifies. The research encompasses comprehensive isolation, identification, and characterization of LAB and yeasts from Ivorian coffee, evaluating their antagonistic properties against mycotoxigenic fungi. Furthermore, the study elucidates the mechanisms underlying the biocontrol activity, shedding light on how these microorganisms mitigate mycotoxin contamination. This research is pivotal in the pursuit of climate-resilient strategies for mycotoxin management, contributing to both food safety and agricultural sustainability.
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    Effect of post-harvest management practices on the mycobiome and ochratoxin A contamination of differently processed Robusta coffees from Ivory Coast
    (Elsevier, 2023-09-15) López Rodríguez, Claudia; Strub, Caroline; Chochois, Vincent; Verheecke-Vaessen, Carol; Durand, Noël; Jourdan, Christophe; Fontana, Angélique; Guehi, Tagro; Medina, Angel; Schorr-Galindo, Sabine
    Ochratoxin A (OTA) is a secondary metabolite produced primarily by the genus Aspergillus sp. sections Circumdati and Nigri. It can accumulate in coffee at post-harvest stage. In the present study five different dry processed coffees were sampled from Ivory Coast at harvesting and after drying. The OTA was detected in all the samples, from 3.62 μg/kg of coffee just after harvest to a higher-level of contamination in the dried coffee, between 11.04 and 760.24 μg/kg of coffee. Metabarcoding was used to further study the changes in the mycobiota. The alpha and beta diversity analysis revealed the presence of unique and more diverse fungal communities on the coffee after drying compared to fresh harvested coffee. Specially, coffee dried for a longer period showed a higher diversity. Fungal species such as Hypopichia sp. or Bernettozyma sp., were replaced in the top ten abundant species after drying by species such as Kurtzmaniella sp., Meyerozyma sp. and Fusarium sp. The increasing abundance of the ochratoxigenic fungi, A. carbonarius was correlated to the increased concentration of OTA on coffee. The construction of the negative correlation network shows that some yeasts could be good candidates for the biocontrol of A. carbonarius. The combination of DNA metabarcoding and OTA quantification was effective at deciphering the post-harvest origin of the OTA contamination. Overall, this study highlights the changes in the mycobiota under different drying conditions. Future perspectives include developing actions of prevention and control of the contamination with OTA during the post-harvest stages.
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    Reduction in ochratoxin a occurrence in coffee: from good practices to biocontrol agents
    (MDPI , 2024-08-01) López-Rodríguez, Claudia; Verheecke-Vaessen, Carol; Strub, Caroline; Fontana, Angélique; Schorr-Galindo, Sabine; Medina, Angel
    Ochratoxin A (OTA) is a mycotoxin mainly produced by Aspergillus section Circumdati and section Nigri across the coffee chain. OTA is nephrotoxic and is a threat to human health. This review summarizes current knowledge on how to reduce OTA concentration in coffee from farm to cup. After a brief introduction to the OTA occurrence in coffee, current good management practices are introduced. The core of this review focuses on biocontrol and microbial decontamination by lactic acid bacteria, yeasts and fungi, and their associated enzymes currently reported in the literature. Special attention is given to publications closest to in vivo applications of biocontrol agents and microbial OTA adsorption or degradation agents. Finally, this review provides an opinion on which future techniques to promote within the coffee supply chain.
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    Resilience to climate change by biocontrol yeasts against Ochratoxin A production in Robusta coffee
    (MDPI, 2025-03-01) López-Rodríguez, Claudia; Verheecke-Vaessen, Carol; Strub, Caroline; Fontana, Angélique; Guehi, Tagro; Schorr-Galindo, Sabine; Medina, Angel
    Aspergillus carbonarius is the main producer of Ochratoxin A (OTA) in coffee. In the last few years, there has been an increasing interest in using yeast isolates as Biocontrol Agents to prevent OTA production in coffee cherries during the primary postharvest processing. Little is known about how climate change abiotic conditions of increased temperature (+2–4 °C), elevated CO2 (existing levels of 400 vs. 1000 ppm), and increased drought stress will impact biocontrol resilience. This study examined the effect of a three-way interaction between temperature (27, 30, and 33 °C) x water activity (aw) (0.90 and 0.95 aw) x CO2 level (400 vs. 1000 ppm) on the growth and OTA production of A. carbonarius and the resilience of three yeast strains’ biocontrol capacity on fresh coffee cherries. High aw (0.95), CO2, and temperature levels increased the production of OTA by A. carbonarius. All the yeast biocontrol strains significantly reduced A. carbonarius growth by at least 20% and OTA production by up to 85%. From the three strains used, the Meyerozyma caribbica strain (Y4) showed the best resilience to climate change, since it reduced both growth (50%) and OTA production (70%) under future scenarios of CO2 and aw at all temperatures tested, and should be the one selected for pilot scale experiments in Ivory Coast.