Detection and quantification of Aspergillus ochraceus in green coffee by PCR.
OBJECTIVE
The aim of this study was to detect and quantify DNA of the ochratoxinogenic fungus Aspergillus ochraceus in green coffee and to compare the results with the ochratoxin A content of naturally contaminated samples.


RESULTS
A DNA extraction protocol based on a combination of ultrasonification and a commercial kit was tested for the recovery of fungal DNA. PCR and real-time PCR protocols were established for the detection of A. ochraceus. Sensitivity of the PCR was checked by the addition of inoculated green coffee and pure fungal DNA to uncontaminated green coffee samples. The A. ochraceus DNA content of 30 naturally contaminated green coffee samples was determined and compared with the ochratoxin A concentrations.


CONCLUSIONS
Aspergillus ochraceus can be rapidly and specifically detected in green coffee by PCR. A positive correlation between the ochratoxin A content and the DNA quantity was established.


CONCLUSIONS
This work offers a quick alternative to the conventional mycological detection and quantification of A. ochraceus in green coffee.
Schmidt
H
H
TU München, Lehrstuhl für Technische Mikrobiologie, Freising, Germany.
Bannier
M
M
Vogel
R F
RF
Niessen
L
L
D001235:Aspergillus ochraceus / Q000235:genetics / Q000302:isolation & purification*; D040503:Coffea / Q000737:chemistry / Q000382:microbiology*; D015169:Colony Count, Microbial / Q000379:methods; D004271:DNA, Fungal / Q000032:analysis / Q000302:isolation & purification; D005506:Food Contamination; D005516:Food Microbiology; D009793:Ochratoxins / Q000032:analysis; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity
D004271:DNA, Fungal; D009793:Ochratoxins; C025589:ochratoxin A