An article in the Los Angeles Times reports that Gallo has confirmed that
traces of TCA have been found in wines bottled at its processing facility in
Sonoma. 90 different Gallo wines totaling nearly 2 million cases a year are
bottled there under such labels as Rancho Zabaco, Frei Brothers, Gallo of
Sonoma and Louis Martini. The chemical is not a health risk but can produce
an unpleasant off-taste in the wine.

TCA is the abbreviation for trichloroanisole, a chemical byproduct of the
interaction between mold and chlorine, which is used as a cleaning solution
and to bleach corks and oak barrels. Contaminated corks are often a source
of TCA in bottled wine. One of the mysteries of the Gallo contamination is
that the winery stopped using chlorine as a cleaning agent years ago

The Times article also mentions that Gallo which produces about a third of
California's wine, is the world's second largest wine producer.

I had thought that Gallo was the largest wine company . I was surprised to
find out elsewhere that the world's largest wine company is Constellation
Brands, a name totally unfamiliar to me although I did recognize its wine
brands.