Occurrence of ochratoxigenic fungi and ochratoxin A in grapes from a Tunisian vineyard.
The occurrence of ochratoxin A (OTA) and the identification of the ochratoxigenic microbiota in Tunisian grapes were studied for the first time. Black aspergilli were the dominant genus among the filamentous fungi isolated from grapes and were the only potential OTA-producing fungi found. The most abundant species were member of Aspergillus niger aggregate (63%) and Aspergillus carbonarius (36%). Uniseriate aspergilli were rarely present (1%). Of the A. carbonarius isolates, 97% were OTA positive but only 3% of the A. niger aggregate isolates were OTA positive. During grape maturation, the frequency of black aspergilli increased due to increase of the numbers of A. carbonarius. Musts (n=24) obtained from grapes collected at the different sampling times were analyzed for their OTA content. Up to 37% of the musts contained OTA at levels varying between 0.59 and 2.57 microg/l. The amounts of OTA in musts increased as grapes matured. These results indicate that A. carbonarius is the main cause of OTA contamination of Tunisian grapes.
Lasram
Salma
S
Laboratoire de Physiologie Moléculaire de la Vigne, Centre de Biotechnologie à la Technopole de Borj Cédria, BP.901, Hammam-Lif 2050, Tunisia.
Bellí
Neus
N
Chebil
Samir
S
Nahla
Zghonda
Z
Ahmed
Mliki
M
Sanchis
Vicente
V
Ghorbel
Abdelwahed
A
D001230:Aspergillus / Q000145:classification / Q000302:isolation & purification*; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D009793:Ochratoxins / Q000032:analysis*; D010802:Phylogeny; D013045:Species Specificity; D014416:Tunisia; D027843:Vitis / Q000737:chemistry* / Q000382:microbiology*; D014920:Wine / Q000032:analysis
D009793:Ochratoxins; C025589:ochratoxin A