Oyster fraud is about more than just getting duped out of a couple bucks. By law, oysters must carry a tag that includes information on the grower or harvester, origin, harvest date, and more. There’s a reason why strong traceability requirements are in place: For the most part, we eat oysters raw. They’re a high-risk food. The CDC found that incidence of vibrio infection, associated with eating raw shellfish, was 43 percent higher in 2012 than it was from 2006 to 2008.

and then there’s oyster poaching:

“If it’s a poached oyster, they’re probably not doing any paperwork on it,” says Steve Vilnit of the Maryland Department of Natural Resources Fisheries Service, paperwork that would include traceable information such as history of temperature controls and harvest location.

“If they’re taking oysters from an area not deemed for consumption—like marinas or sewage areas—someone could get very sick on that,” he says.

Jon Rowley (quoted in the article) and others recommend asking to see the shipping tag to confirm origin, harvest site, and shipping date. (Coastodian.org shares an image of what these tags look like and the information contained thereon.) But this advice seems to beg the question: If someone’s intent on passing off shellfish as something other/better than what it is, what would keep them from forging or modifying a tag, or otherwise giving the consumer wrong information.