A UBC researcher has found the potentially deadly listeria bacterium in ready-to-eat seafood in stores around the Lower Mainland – but in concentrations that aren't a health threat for most people.

Although the levels of the bacteria didn't exceed federal guidelines, the strains present are alarming, said food microbiologist Kevin Allen at the University of British Columbia.

The researchers tested 40 products, including smoked tuna, lox, candied salmon and fish jerky from seven large grocery chains and 10 smaller retailers, which he did not identify. Twenty per cent of the food they tested contained listeria and 5 per cent of those products had the more dangerous form of listeria monocytogenes – a strain linked to the 2008 Canadian listeriosis outbreak in which 23 people died after eating contaminated deli meats.

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Mr. Allen says those particularly vulnerable to food-borne illness, including pregnant women and people with compromised immune systems, should avoid such seafood.