Ochratoxigenic fungi associated with green coffee beans (Coffea arabica L.) in conventional and organic cultivation in Brazil

Abstract

The genera Aspergillus comprises species that produce mycotoxins such as aflatoxins, ochratoxins and patulin. These are cosmopolitan species, natural contaminants of agricultural products. In coffee grains, the most important Aspergillus species in terms of the risk of presenting mycotoxins belong to the genera Aspergillus Section Circumdati and Section Nigri. The purpose of this study was to assess the occurrence of isolated ochratoxigenic fungi of coffee grains from organic and conventional cultivation from the South of Minas Gerais, Brazil, as well as to evaluate which farming system presents higher contamination risk by ochratoxin A (OTA) produced by fungi. Thirty samples of coffee grains (Coffea arabica L.) were analysed, being 20 of them of conventional coffee grains and 10 of them organic. The microbiological analysis was done with the Direct Plating Technique in a Dichloran Rose Bengal Chloramphenicol Agar (DRBC) media. The identification was done based on the macro and micro morphological characteristics and on the toxigenic potential with the Plug Agar technique. From the 30 samples analysed, 480 filamentous fungi of the genera Aspergillus of the Circumdati and Nigri Sections were isolated. The ochratoxigenic species identified were: Aspergillus auricoumus, A. ochraceus, A. ostianus, A. niger and A. niger Aggregate. The most frequent species which produces ochratoxin A among the isolated ones was A. ochraceus, corresponding to 89.55%. There was no significant difference regarding the presence of ochratoxigenic A. ochreceus between the conventional and organic cultivation systems, which suggests that the contamination risk is similar for both cultivation systems.

Evaluation of the effects of temperature on processed coffee beans in the presence of fungi and ochratoxin A

“…However, A. ochraceus were not identified in the samples from the Southern region of Minas Gerais. These results differ from those reported by Rezende, Borges, Cirilo, Prado, and Batista () and Batista and Chalfoun () for coffee from the Southern region of the state of Minas Gerais. Rezende et al () reported the incidence of 35.20% A. ochraceus , whereas Batista and Chalfoun () reported 91.81% A. ochraceus in different coffee fractions.…”

“…These results differ from those reported by Rezende, Borges, Cirilo, Prado, and Batista () and Batista and Chalfoun () for coffee from the Southern region of the state of Minas Gerais. Rezende et al () reported the incidence of 35.20% A. ochraceus , whereas Batista and Chalfoun () reported 91.81% A. ochraceus in different coffee fractions. This decrease in the incidence of potentially ochratoxigenic species in this region may be related to the adoption by the producers of preventive measures during the drying and storage stages (Caixeta, Guimarães, & Malta, ).…”

“…In processed green coffee beans, Rezende et al () observed a 27.29% incidence of Aspergillus species of section Circumdatti and 29.25% of section Nigri . However, Batista and Chalfoun () found higher numbers of Aspergillus species of the Circumdatti section (41%) when compared with those of the Nigri section (25%) in processed coffee beans.…”

“…The results obtained by Equation for the growth of A. carbonarius using the current temperatures show that the Cerrado region is the closest to the ideal growth conditions, corroborating the results of the procedures performed in the laboratory, where A. carbonarius was isolated only in beans from the Cerrado region. A. carbonarius is not very common in coffee in a directed study with conventional and organic coffee beans found no A. carbonarius isolates (Rezende et al, ).…”

Association of Mycoflora with Coffee (Coffea arabica L.) Beans at Limmu Coffee Plantation, Southwestern Ethiopia

“…The contamination of coffee beans by fungi affects both the quality in terms of flavor and aroma of the beverage and presents a safety risk to the final product due to the production of toxic secondary metabolites, the mycotoxins, which can be harmful to consumers at certain concentrations (Bennett and Klich, 2003;Vilela et al, 2010;Rezende et al, 2013). Plant Pathol.…”