Effect of chemical treatments on ochratoxigenic fungi and common mycobiota of grapes (Vitis vinifera).
The effect of the application of two fungicides (cyprodinil alone and a mixture of cyprodinil and fludioxonil) on the mycoflora of grapes, especially ochratoxigenic fungi, was studied. Different doses and application times were analyzed. Grape mycobiota was isolated and identified, and the classification of black aspergilli was carried out. We found that 81.7% of the isolates belonged to Aspergillus niger aggregate and 18.3% to Aspergillus carbonarius. The ability to produce ochratoxin A (OTA) was studied on Czapek yeast extract agar (CYA) medium in 238 isolates. Most A. carbonarius (97.2%) produced detectable amounts of OTA, while only 2.9% of the A. niger aggregate were OTA producers. Most of the isolates (58%) produced less than 2.5 microg OTA per g of CYA. That, together with the highest levels of black aspergilli detected near harvest, proved the reported theory that they are primarily responsible for OTA in grapes. The fungicides studied had a significant effect on black aspergilli in three of the four vineyards sampled, as the natural increase of black aspergilli when approaching harvest was in general lower in all the fields treated with fungicides as compared to the control treatment. A mixture of cyprodinil (37.5%) and fludioxonil (25%) applied at veraison and 21 days before harvest was the most effective treatment to prevent black aspergilli in grapes, together with a single application of this mixture at veraison followed by an application of cyprodinil (50%) 21 days before harvest. No OTA was detected in musts (n=112) produced from either the control treatment or the treated grapes.
Bellí
Neus
N
Food Technology Department, CeRTA-UTPV, University of Lleida, Av. Alcalde Rovira Roure 191, 25198 Lleida, Spain.
Marín
Sonia
S
Argilés
Elionor
E
Ramos
Antonio J
AJ
Sanchis
Vicente
V
D001230:Aspergillus / Q000187:drug effects* / Q000302:isolation & purification / Q000378:metabolism*; D001234:Aspergillus niger / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D004149:Dioxoles / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005506:Food Contamination / Q000032:analysis / Q000517:prevention & control; D005516:Food Microbiology; D005659:Fungicides, Industrial / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D009793:Ochratoxins / Q000096:biosynthesis*; D011743:Pyrimidines / Q000494:pharmacology; D011758:Pyrroles / Q000494:pharmacology; D013997:Time Factors; D027843:Vitis / Q000737:chemistry / Q000382:microbiology*; D014920:Wine / Q000382:microbiology / Q000592:standards
D004149:Dioxoles; D005659:Fungicides, Industrial; D009793:Ochratoxins; D011743:Pyrimidines; D011758:Pyrroles; C025589:ochratoxin A; C108338:cyprodinil; C108339:fludioxonil