DES MOINES, Iowa (AP) - A massive frozen foods recall involves millions of packages of fruits and vegetables that were shipped to all 50 U.S. states, Canada and Mexico.

Authorities who want to stem the listeria-linked illnesses and deaths worry it'll be difficult to get consumers to dig through their freezers and check for products they may have bought as far back as 2014.It's one of the largest food recalls in recent memory, with well over 400 products from CRF Frozen Foods in Pasco, Washington, sold under more than 40 different brand names at major retailers like Costco, Target, Trader Joe's and Safeway.Products include McCain, Simply Nature, Great Value and Season's Choice.So far, eight people have been sickened by listeria that's genetically similar to that found in CRF vegetables, and two have died, though listeria was not the primary cause of death.The initial recall started April 22, covering 11 frozen vegetable products. On May 2, CRF expanded it to include all of its frozen organic and traditional fruit and vegetable products manufactured or processed at its Washington plant since May 1, 2014.The CRF plant closed two weeks ago and Grabowski said the company is still trying to pinpoint the source of the contamination.Wise said his concern is that consumers check the online recall lists and discard the products from their freezers."Listeriosis always makes us worry because it's such a serious infection," he said. The CDC says listeria is most harmful to adults over 65 with weakened immune systems and pregnant women.The CDC continues to monitor state illness reports for any sign of additional cases, Wise said.Listeria causes an estimated 1,600 cases illnesses each year in the U.S., but just half are reported. About 18 percent of listeriosis patients die.FDA spokeswoman Lauren Sucher said it's important to follow label directions for cooking frozen foods and to check freezers thoroughly for the products listed on the FDA website.