IntraFish dove into listeria this week, from recalls and outbreaks to prevention methods and the zero tolerance policy.

But one question lingered: how listeria-free are smoked salmon products at US retail?

IntraFish partnered with IEH Laboratories & Consulting Group to test several smoked salmon samples taken from US supermarket shelves.

Mansour Samadpour, principal at IEH, previously worked with early detection of foodborne illnesses at the University of Washington.

“I started thinking maybe we can detect [these diseases] to prevent outbreaks, so I started IEH in 2001,” he told IntraFish.