A large recall of frozen produce that may be contaminated with Listeria has many consumers wondering if they should be worried. So far eight people in three states have become sick, and officials believe that the problem originated at a certain frozen foods plant. Here's what you need to know.

Which products are affected? The recalled foods all come from CRF Frozen Foods of Pasco, Washington. That particular plant blanches, freezes, and packages produce for a wide range of retailers and brands all over the country, like Trader Joe's, Safeway and Columbia River Organics. All told, the recall affects over 350 different products sold under 42 brand names, including items like organic broccoli, stir-fry medleys and berries. All of the products have a sell-by or best-by date between April 26, 2016 and April 26, 2018. CRF Frozen Foods' press release on the recall has the exact list of all 358 products that may be contaminated.

What should I do if I bought one of the items affected? Don't eat it. Either throw it away or return it to the store where you bought it for a refund.

Is Listeria a big deal? Listeria monocytogenes bacteria can be deadly, especially in older people or those with weakened immune systems. In pregnant women, it can cause miscarriage or stillbirth.

How did this happen? Officials are not yet sure exactly how the listeria outbreak began, but the bacteria differs from others in that it can survive in cold temperatures, though heat does kill it. (Last year, Blue Bell Creamery had to issue a recall for ice cream contaminated with Listeria.) The bacteria is hardy and can live on processing plant equipment and contaminate everything that comes in contact with it. So one hypothetical scenario is that the produce was contaminated by contact with the bacteria after blanching and before packaging. From there, the contaminated food made its way to all 50 states and Canada.

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