Impact of non-selective fungicides on growth and production of ochratoxin A by Aspergillus ochraceus and A. carbonarius in barley-based medium

Eva M. Mateo (1) , Francisco M. Valle-Algarra (2) , Misericordia Jiménez (3) , Rufino Mateo Castro (4)

1 Dpt. Microbiology and Ecology
2 Dpt. Analytical Chemistry
3 Microbioloby and Ecology
4 Departamento de Química Analítica

The aim of the present study was to assess the influence of the non-selective fungicides mancozeb, copper oxychloride and sulfur on the growth and capability for producing ochratoxin A (OTA) of ochratoxigenic isolates of Aspergillus carbonarius and A. ochraceus in barley-based medium. Lag phases and growth rates were determined for each fungicide at different doses, at 15 ºC and 25 ºC and at 0.97 aw. Mancozeb at 40 mg L-1 inhibited fungal growth and provided lag phases > 24 days at 10-20 mg L-1 and 15 ºC. OTA was observed only at 25 ºC and doses <10 mg L-1. At 15 ºC, copper oxychloride proved inhibitory at 800 mg L-1 while at 25 ºC growth was not delayed and only high doses decreased OTA levels. Sulfur was inhibitory or provided large lag phases at 5-8 g L-1 (at 15 ºC) while at 25 ºC growth took place even at 8 g L-1 although OTA levels were low or undetectable. The antifungal activity decreased in the order mancozeb > copper oxychloride > sulfur and was lower at 25 ºC than at 15ºC. OTA accumulation was affected by the fungicide, dose, temperature and time. The efficacy of these fungicides on the growth of A. carbonarius and A. ochraceus and OTA production in barley-based medium is assessed for the first time.

Mots clés: Life Sciences

Eva M. Mateo, Francisco M. Valle-Algarra, Misericordia Jiménez, Rufino Mateo Castro. Impact of non-selective fungicides on growth and production of ochratoxin A by Aspergillus ochraceus and A. carbonarius in barley-based medium. Food Additives and Contaminants, 2010, pp.1. ⟨10.1080/19440049.2010.529621⟩. ⟨hal-00647402⟩