Wikipedia's Thiamine / antagonists section: >Thiamine in foods can be degraded in a variety of ways. Sulfites, which are added to foods usually as a preservati

Wikipedia's Thiamine / antagonists section: >Thiamine in foods can be degraded in a variety of ways. Sulfites, which are added to foods usually as a preservative,[34] will attack thiamine at the methylene bridge in the structure, cleaving the pyrimidine ring from the thiazole ring.[13] The rate of this reaction is increased under acidic conditions. Thiamine is degraded by thermolabile thiaminases (present in raw fish and shellfish[12]). Some thiaminases are produced by bacteria. Bacterial thiaminases are cell surface enzymes that must dissociate from the membrane before being activated; the dissociation can occur in ruminants under acidotic conditions. Rumen bacteria also reduce sulfate to sulfite, therefore high dietary intakes of sulfate can have thiamine-antagonistic activities. Is this perhaps due to sulfate pollution (bunker oil?) and acidification of the oceans?