NEW YORK (AP) — U.S. health officials are warning the public not to eat certain brands of packaged salads, which they say are linked to two small, long-running listeria outbreaks in which three people died.

One outbreak is linked to packaged salads produced by Fresh Express and another has been tied to packaged salads produced by Dole. The outbreaks are caused by different strains of listeria bacteria and there’s no known link between them, the Centers for Disease Control and Prevention reported Thursday.

In the outbreak linked to Fresh Express, ten people in eight states were identified in the outbreak between 2016 and late October of this year. All were hospitalized and one person, in Pennsylvania, died.

This week, Fresh Express recalled several brands of packaged salad products with product codes Z324 through Z350. The CDC is telling people not to eat, sell, or serve any recalled products.

A separate outbreak caused by a different strain was found on two Dole packaged salads. In that outbreak, 16 people in 13 states infected with the listeria strain have been reported between August 2014 and mid-October of this year. That includes 12 who were hospitalized and two — in Michigan and Wisconsin — who died.

Dole recalled several brands of packaged salads this week with “best if used by” dates from Nov. 30 to Jan. 8.

It’s not known where the listeria originated in either outbreak, but it’s a hardy bacteria that can linger on surfaces in production facilities or other places, officials say.

Listeria symptoms usually start one to four weeks after eating contaminated food, but can start as soon as the same day.

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