Over the last few years, the U.S. import market has seen errant products from China - from toys to party favors.  Now, it appears that the food industry is subject to warnings and recalls.

Pine Nuts - an integral ingredient to pesto, are expensive.  Like most products, you get what you pay for.  Recently, the Chinese have entered the Pine Nut market, exporting a cheaper-variety that is leaving some unsuspecting eaters with what's being called "Pine Mouth" or "PNS".  Everything they eat afterwards tastes tinny;  Even the air that they breathe in has this taste trait.  This symptom has been known to last up to 9 weeks.

PNS has been identified as an emerging problem in the Journal of Medical Toxicology, and is being actively investigated by the U.K. food standards agency, and European Union food safety groups.

A January 2011 report in the Journal of Toxicology suggests that taste disturbances following consumption of pine nuts is related to a species from southern China, the Pinus armandii (white pine).

Chinese white pine, until recently, was harvested only for lumber, resin or turpentine. It is a relative newcomer to the billion-dollar-a-year global pine nut market.

U.S. suppliers are taking note and making changes to their product lines.

Food industry baffled by cause of tinny-tasting ‘pine mouth’.