Occurrence of Ochratoxin A–Producing Fungi in Raw Brazilian Coffee

Abstract

Ochratoxin A (OA)-producing fungi were identified in coffee at different stages of maturation. The toxin was quantified in coffee during terrace drying and in coffee stored in barns. By direct plating, a high level of contamination (100%) was found in the coffee beans studied, with the genus Aspergillus representing 33.2%, of which Aspergillus ochraceus and Aspergillus niger represented 10.3 and 22.9%, respectively, of the strains isolated from the coffee beans. The capacity to produce ochratoxin was determined in 155 strains of A. ochraceus and A. niger using both the agar plug method and extraction with chloroform, giving positive results for 88.1% of the A. ochraceus strains and 11.5% of the A. niger strains. Analysis for OA in the terrace and barn coffee samples showed that, independent of cultivar, year harvested, or production region, all except one of the samples analyzed showed mycotoxin levels below the limit suggested by the European Common Market (8 microg/kg), thus indicating that the problem is restricted and due to severe faults in harvesting and storage practices.

Incidence and distribution of filamentous fungi during fermentation, drying and storage of coffee (Coffea arabica L.) beans

“…These differences found in the number and diversity of fungi in the coffee beans could be related with the long period of fermentation and drying (15-25 days). This high frequency and diversity of fungi in green coffee samples analyzed at different stages of maturation and processing was also reported by Urbano et al (37) and Pardo et al (21). A high diversity of fungi species was observed in cherries collected from trees.…”

“…A. ochraceus was found only at the 20 th day of fermentation, not being detected during storage. Aspergillus species have been frequently reported in beans and stored grains of coffee (3,4,6,7,17,32,33,35,37). Besides compromising the quality of the product, the presence of Aspergillus may affect their safety due to production of secondary metabolites toxic to man and animals (mycotoxins).…”

Ecological conditions affecting mycotoxin production in cereals: a review

“…It has also been described as a potent nephrotoxin and teratogen, with immunotoxic properties in rats and possibly in humans. Ochratoxin A has been extensively documented as a global contaminant of a wide variety of foods including cereal products, nuts, spices and coffee (Zimmerli and Dick 1996;Urbano et al 2001). The highest amounts of ochratoxin A were obtained at 0.98 a w , regardless of the temperature level, with optimum ochratoxin A production occurring between 25-30 °C, depending on the isolates.…”

Obtenção de mutantes de Aspergillus carbonarius via transformação genética mediada por Agrobacterium tumefaciens

“…Em uma grande variedade de produtos agrícolas em várias regiões geográficas do mundo já foi detectada a ocratoxina A (URBANO et al, 2001). Muitos destes alimentos são grãos, como cevada, milho, centeio, trigo e aveia (JORGENSEN; JACOBSEN, 2002), além de estar presente em outros produtos incluindo café, especiarias, nozes, azeitonas, uvas, e figos (BATTILANI et al, 2003;BATISTA et al, 2003;BAYMAN et al, 2002;JORGENSEN, 1998).…”