my point is about selling proposition of that probiotic - production of ethanol which i'd not expect to be long term healthy on its own merits, even without formate.
Various metabolic processes in the body already produce methanol and ethanol. Now as to the relative quantities involved, I have no idea what can be produced by bacteria in the mouth.
Yeah, that is the big question here... how much is being produced. Also, how variable is the product from batch to batch? Could one batch be producing byproducts at much higher quantities than another batch?