Browsing by Author "Guehi, Tagro"

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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, 2024-03-01) López Rodrígue, 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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    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.