Colloidal silver complex as an alternative to sulphur dioxide in winemaking

The use of sulphur dioxide in the food industry has come increasingly into question because it can lead to pseudo-allergies. The aim of this work was to study the effectiveness of a colloidal silver complex (CSC) as an antiseptic instead of SO2 in both white and red winemaking. We show that the CSC at doses of 1 g/kg of grape is an effective antiseptic, able to control acetic acid and lactic acid bacteria development, allowing the growth of Saccharomyces cerevisiae at rates similar to those observed with SO2, up to sugars were exhausted. Silver concentration in finished white and red wines, 18.4 μg/L and 6.5 μg/L, respectively, was well below the legal limits. Wine composition was slightly affected, but CSC wines had a lower alcoholic degree and acetaldehyde content than SO2 wines. CSC is a promising antiseptic for wine industry, although a major drawback, its lack of antioxidant activity, should be considered.