TCA Cork Taint and How did Trichloroanisole get in my Wine?

Trichloroanisole is found produced by fungus, often on
corks. 

Ever bought a bottle of over-price old wine and found that the bottle was spoiled? The fungus growing on the cork produces trichloro-anisole which wine-jocks say smells like wet dog or damp basement.

This brings up several issues: why arn't the corks sterilized? And where does the chlorine come from to make the trichloro-anisole? And most importantly, how poisonous is trichloro-anisole?

Why are natural corks sterilized? I am sure people try but cork is even worse than wood for sterilization. Cork might be quant, but it isn't a very good material, and probably should not regarded as food grade. Old fashion traditionalists need to grow up.

Some say that the source is chlorine-containing air pollutants on the trees that grow the cork. It is more likely that it is due to the wood preservative trichloro-phenol that is used with wood barrels. Another source of chlorine is from the use of bleach and related oxidizers as cleaning agents.

Chlorine bleach reacts with wine residue and living microbes to make chlorinated byproducts -- some of which may be carcinogenic. You need to rinse a lot after using bleach, and dirt that reacts with bleach may be hard to see -- but still could contain chlorinated compounds that are harmful. Trichloro-anisole is not carcinogenic however -- so don't worry.

The alternative to chlorine bleach is sulfite containing materials, and these make a familiar rotten eggs smell if over used. Not as dangerous as trichloro-anisole, but less appetizing too. The best is using ozone but that is not practical at home, or is barely practical. More on that later. Another non-toxic sterilization agent is hydrogen peroxide.