Impact of pre-harvest elicitors on the toxigenic mycobiota and mycotoxin risk in dried figs: A holistic safety assessment

Résumé fourni par la source

Pre-harvest fungal contamination of figs ( Ficus carica L.) poses a significant food safety risk due to mycotoxin production. While chemical elicitors are proposed as a sustainable control strategy, their impact on the autochthonous mycobiota and mycotoxin profiles during fig maturation and sun-drying is largely unknown. This study evaluated the effects of pre-harvest applications of γ-aminobutyric acid (GABA), oxalic acid (OA), and melatonin (MT) on the fungal community dynamics and 16 mycotoxins across five ripening and senescence stages of ‘Calabacita’ figs. Results showed a clear ecological succession from field fungi ( Cladosporium spp.) in unripe figs to xerotolerant storage fungi ( Aspergillus spp.) in dried figs. MT treatments demonstrated a protective effect, significantly reducing final moisture content to below the 26% safety threshold and limiting the prevalence of toxigenic species. In contrast, the 10 mM GABA treatment, despite reducing overall mould counts in some stages, selectively fostered a high-risk consortium of toxigenic fungi ( A. niger , Aspergillus section Flavi ) and their mycotoxins, leading to co-contamination with aflatoxins (AFB 1 , AFB 2 , AFG 1 ), cyclopiazonic acid (CPA), and O -methyl-sterigmatocystin (OM-STG). While MT shows promise as a pre-harvest strategy to enhance the microbiological safety of dried figs, the 10 mM GABA treatment proved detrimental. These findings highlight the critical need for a holistic risk assessment of elicitors, considering their unintended and sometimes paradoxical effects on the native mycobiota and the resulting mycotoxin risk.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.