Bacteria, yeasts and filamentous fungi were isolated during natural coffee processing. Bacteria w... more Bacteria, yeasts and filamentous fungi were isolated during natural coffee processing. Bacteria were isolated in greater numbers at the beginning of the fermentation, when the moisture of the coffee beans was around 68%. Gram-positive bacteria represented 85.5% of all bacteria isolated, and Bacillus was the predominant genus (51%). Gram-negative species of the genera Serratia, Enterobacter and Acinetobacter were also found. Approximately 22% of 940 randomly chosen isolates of microorganisms were yeasts. Debaryomyces (27%), Pichia (18.9%) and Candida (8.0%) were the most commonly found genera, and these three genera tended to appear more often as the fruit was fermented and dried. Aspergillus was the most abundant genus besides Penicillium, Fusarium and Cladosporium, with 42.6% of the total fungi isolates. The genera and species identified included members known to have pectinase and cellulase activities. Of the 10 organic acids analyzed and quantified in coffee beans, acetic and lactic acids may have been generated by microbial activity. Butyric acid was not detected in any sample. (R.F. Schwan).
Processed (green) coffee beans from Coffea arabica in Brazil were assessed for the presence of As... more Processed (green) coffee beans from Coffea arabica in Brazil were assessed for the presence of Aspergillus and Penicillium species both before and after surface sterilisation, the aflatoxigenic and ochratoxigenic potential of the isolates and ochratoxin A levels. Contamination by Aspergillus and Penicillium species was found on 96% and 42%, respectively, of 45 samples from 11 localities. After disinfection with 1% sodium hypochlorite, the levels fell to 47% and 24%, respectively. One hundred and eighty isolates were identified to species level and comprised Aspergillus sections Circumdati (10 species), Flavi (3), Nigri (3), Versicolores (4), while two were teleomorphic species. Eight species of Penicillium were isolated. Within section Circumdati, 75% of the isolates produced ochratoxin A and all except Aspergillus elegans and Aspergillus insulicola have previously been reported to produce ochratoxin A. One-third of the 18 isolates of Aspergillus flavus produced aflatoxin B 1 and B 2 . None of the isolates belonging to Aspergillus section Nigri or Penicillium produced ochratoxin A. Of the 40 bean samples analysed, 58% were infected with potentially ochratoxigenic fungi but only 22% of these were contaminated with ochratoxin A at levels that varied from 0.47 to 4.82 ng/g, with an average contamination level of 2.45 ng/g. D
The incidence of ochratoxin A was studied in different coffee (Coffea arabica L.) samples. A high... more The incidence of ochratoxin A was studied in different coffee (Coffea arabica L.) samples. A higher incidence of filamentous fungi was observed in the coffee swept from ground and floating coffee samples. The species Aspergillus ochraceus, Aspergillus sulphureus and Aspergillus sclerotiorum were ochratoxin A producing. In 128 (44%) samples ochratoxin A was not detected; however, in 89 samples (31%), ochratoxin A was detected at 0.1-5.0 lg/Kg levels. Other 25% samples presented contamination above 5.0 lg/Kg. This study showed that the fractions coffee swept from ground and floating coffee represents a serious risk of ochratoxin A contamination.
Bacteria, yeasts and filamentous fungi were isolated during natural coffee processing. Bacteria w... more Bacteria, yeasts and filamentous fungi were isolated during natural coffee processing. Bacteria were isolated in greater numbers at the beginning of the fermentation, when the moisture of the coffee beans was around 68%. Gram-positive bacteria represented 85.5% of all bacteria isolated, and Bacillus was the predominant genus (51%). Gram-negative species of the genera Serratia, Enterobacter and Acinetobacter were also found. Approximately 22% of 940 randomly chosen isolates of microorganisms were yeasts. Debaryomyces (27%), Pichia (18.9%) and Candida (8.0%) were the most commonly found genera, and these three genera tended to appear more often as the fruit was fermented and dried. Aspergillus was the most abundant genus besides Penicillium, Fusarium and Cladosporium, with 42.6% of the total fungi isolates. The genera and species identified included members known to have pectinase and cellulase activities. Of the 10 organic acids analyzed and quantified in coffee beans, acetic and lactic acids may have been generated by microbial activity. Butyric acid was not detected in any sample. (R.F. Schwan).
Processed (green) coffee beans from Coffea arabica in Brazil were assessed for the presence of As... more Processed (green) coffee beans from Coffea arabica in Brazil were assessed for the presence of Aspergillus and Penicillium species both before and after surface sterilisation, the aflatoxigenic and ochratoxigenic potential of the isolates and ochratoxin A levels. Contamination by Aspergillus and Penicillium species was found on 96% and 42%, respectively, of 45 samples from 11 localities. After disinfection with 1% sodium hypochlorite, the levels fell to 47% and 24%, respectively. One hundred and eighty isolates were identified to species level and comprised Aspergillus sections Circumdati (10 species), Flavi (3), Nigri (3), Versicolores (4), while two were teleomorphic species. Eight species of Penicillium were isolated. Within section Circumdati, 75% of the isolates produced ochratoxin A and all except Aspergillus elegans and Aspergillus insulicola have previously been reported to produce ochratoxin A. One-third of the 18 isolates of Aspergillus flavus produced aflatoxin B 1 and B 2 . None of the isolates belonging to Aspergillus section Nigri or Penicillium produced ochratoxin A. Of the 40 bean samples analysed, 58% were infected with potentially ochratoxigenic fungi but only 22% of these were contaminated with ochratoxin A at levels that varied from 0.47 to 4.82 ng/g, with an average contamination level of 2.45 ng/g. D
The incidence of ochratoxin A was studied in different coffee (Coffea arabica L.) samples. A high... more The incidence of ochratoxin A was studied in different coffee (Coffea arabica L.) samples. A higher incidence of filamentous fungi was observed in the coffee swept from ground and floating coffee samples. The species Aspergillus ochraceus, Aspergillus sulphureus and Aspergillus sclerotiorum were ochratoxin A producing. In 128 (44%) samples ochratoxin A was not detected; however, in 89 samples (31%), ochratoxin A was detected at 0.1-5.0 lg/Kg levels. Other 25% samples presented contamination above 5.0 lg/Kg. This study showed that the fractions coffee swept from ground and floating coffee represents a serious risk of ochratoxin A contamination.
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