Advances in Food Mycology

Black Aspergillus Species in Australian Vineyards 159
Harvested bunches were chilled at 4°C prior to crushing. After
crushing, eight samples of must from each toxin level were collected in
order to establish the initial total OA present in the berries. Samples
were also collected throughout the vinification process as described
below.
During white vinification, the must was pressed, after which potassium
metabisulphite was added to give 50 ppm SO 2 in the juice.
Pectinase was added in the form of Pomolase AC50 (0.05 ml/l
juice; Enzyme Solutions, Victoria, Australia) or Pectinase (0.5 g/l
juice; Fermtech, Queensland, Australia). The juice was overlaid with
nitrogen or carbon dioxide, and refrigerated at 4°C for at least 24 h to
precipitate solids. In 2002, the juice was divided into four replicate
ferments at each toxin level before clarification; this division occurred
after clarification in 2003. The pH was adjusted to approximately 3.3
by the addition of tartaric acid to give a titratable acidity of 6.5-7.0
g/l. The clarified juice was siphoned into bottles filled with nitrogen or
carbon dioxide and fitted with stoppers and air traps. The yeast QA23
(Lallemand, Toulouse, France) was rehydrated and added at a rate
equivalent to 0.2 g dry yeast/l juice. Diammonium phosphate was
added at 0.5 g/l juice. The fermentation temperature was 19°C in 2002
and 15°C in 2003. Diammonium phosphate was added during fermentation
as required and after fermentation was completed, the wine
was racked. Potassium metabisulphite was added at a rate equivalent
to 50 ppm SO 2 to stabilise the wine and prevent further fermentation.
Bentonite (0.5 g/l; Fermtech, Queensland, Australia) and Liquifine
(2002: 1 ml/l; 2003: 0.6 ml/l; Winery Supplies, Victoria, Australia) were
added, and the bottles placed at 19°C (2002) or 15°C (2003) to allow
precipitation of solids. A second racking was performed for all bottles,
and potassium metabisulphite was added to bring the free SO 2 to 20
ppm. The bottles were placed at < 4°C for cold stabilisation for > 30
days. The wine was filtered into 375 ml glass bottles with cork
closures.
During red vinification, the must was divided into 4 replicate fermentations
at each toxin level. Potassium metabisulphite was added to
give 50 ppm SO 2 in the must, diammonium phosphate was added at
0.5 g/l must, and tartaric acid was added to bring the titratable acidity
to 6.5 g/l. The yeast D254 (Lallemand, Toulouse, France) was rehydrated
and added at approximately 0.3 g/l must. The cap was plunged
2-3 times daily. The must was pressed after 4 days of fermentation at
room temperature in 2002, and after 6 days of fermentation at approximately
20°C in 2003. Fermentation was finished in bottles at room
temperature. During the first racking, 50 ppm SO 2 was added, after