Black Aspergillus species as ochratoxin A producers in Portuguese wine grapes

Abstract

To evaluate the incidence of fungi producing ochratoxin A (OA) in Portuguese wine grapes, a survey was conducted in 11 vineyards, from four winemaking regions each with distinct climatic conditions. From setting to the harvesting period, a total of 1,650 berries were sampled by plating methods. Out of 370 aspergilli and 301 Penicillium strains isolated, 14% of the aspergilli were OA-producing strains. None of the penicillia were OA-producing strains. The black aspergilli were predominant (90%). All Aspergillus strains were tested in vitro for OA production and all were preserved in the Micoteca da Universidade do Minho (MUM) culture collection. Most of the Aspergillus carbonarius (97%) and 4% of the Aspergillus niger aggregate strains were OA producers. Almost all ochratoxigenic strains were isolated at harvest time, mainly in the regions with a Mediterranean climate. In the vineyards sampled, the percentage of colonized berries with ochratoxigenic strains was up to 38%. The vineyards from the region with Atlantic influences, with high rainfall, exhibited the lowest occurrence of Aspergillus and ochratoxigenic strains, 0% to 10% and 0% to 2% colonized berries, respectively. Data obtained here supports the hypothesis that A. carbonarius and occasionally A. niger, are the main producers of OA in grapes. In this study, the highest incidence of these fungi occurred in vineyards with a Mediterranean climate.

Molecular detection of ochratoxigenic Aspergillus species isolated from coffee beans in Saudi Arabia

“…It has been suggested that A. carbonarius could be the major cause of OTA production in grapes and derivatives (Cabañes et al, 2002) mainly in the Mediterranean region (Serra et al, 2003), and that A. ochraceus could be the main source of OTA in coffee (Logrieco et al, 2003;Taniwaki et al, 2003). The aim of the present study was to identify the contaminate species of Aspergillus found inside of coffee beans.…”

“…Such studies involve RFLPs of both nuclear and mitochondrial DNA, polymerase chain reaction (PCR)-based methods and phylogenetic analysis (Abarca et al, 2004;Geiser et al, 2007;Perrone et al, 2007;Samson et al, 2007). Furthermore, some black Aspergillus species have been described recently, for instance A. brasiliensis (Varga et al, 2007), A. ibericus (Serra et al, 2003), A. uvarum (Perrone et al, 2008), andA. vadensis (de Vries et al, 2005).…”

Detection and Genotoxicity of Ochratoxin A (OTA) in Raisins

“…The mycoflora of raisins was determined as described (Serra, 2003). A total of 10 raisins of each sample were planted in the medium Dichloran RoseBengal chloramphenicol (Oxoid CM727) and were incubated at 25 ° C in darkness for 1 week.…”

Wine Contamination with Ochratoxins: A Review

“…japonicus is also occasionally isolated from grapes, but its production ability in vitro has not been demonstrated yet [12,15,17,24]. A. uvarum is also an uniseriate species that is included in Aspergillus section Nigri that has been reported to occur in grapes in Mediterranean countries but any isolate has been described as OTA producer [34].…”