Frozen vegetables are a staple in many diets, so a huge recall of them has us peering at the packages in our freezers.
On Tuesday evening, the U.S. Centers for Disease Control and Prevention announced and frozen vegetables and fruits are believed to be the cause.
More than 350 products like green beans, broccoli, peas and blueberries sold under 42 brands at U.S. and Canadian grocers including Safeway, Costco and Trader Joe鈥檚 have now been recalled.
Here are the four things to know about listeria and this massive recall:
Listeria is deadly.
Although than other foodborne pathogens like salmonella or E. coli, listeria is the most lethal.聽Most healthy immune systems can keep an infection at bay, but if the bug makes it into the bloodstream, it causes listeriosis and kills one in five victims.
Older adults, pregnant women, newborns and those with weakened immune systems are at higher risk of infection. People 65 and older are four times more likely to get sick from listeria than the general population, and pregnant women 鈥� who may not develop listeriosis themselves but whose babies could be threatened 鈥� are 10 times more likely.
So far, the CDC knows of eight people who have been sickened 鈥� six in California and one each in Washington and Maryland. The Washington and Maryland patients died, but listeria was not considered the ultimate cause of death. The patients were between 56 and 86 years old.
New tools led to this recall.
The outbreak making headlines today began in 2013 with one illness, followed by five in 2015 and two in 2016. It may seem as if this outbreak is unfolding in slow motion, but that is because the CDC has a new tool to track the bacteria鈥檚 spread: the sequenced genome of listeria.
While investigating a small cluster of 2016 illnesses, the CDC searched its database of previously sequenced listeria genomes and found matches from bacteria that sickened people in previous years.
CDC鈥檚 venture into whole-genome sequencing has allowed the agency to identify more listeria outbreaks, especially more that span longer periods of time. Last year, they announced two outbreaks that began in 2010.
Listeria gets around 鈥� and stays around.
The CDC said that frozen vegetables produced by CRF Frozen Foods in Pasco, Washington, are the 鈥渓ikely source鈥� of the illnesses.
Michael Doyle, professor of food microbiology at the University of Georgia and director of the school鈥檚 Center for Food Safety, said he thinks that 鈥渞esident鈥� listeria caused the outbreak. Rather than 鈥渢ransient鈥� bacteria that contaminates a food and moves through the processing system with it, resident bacteria establishes itself somewhere in the machinery and persists over several years.
鈥淭he organism鈥檚 quite hardy,鈥� he said.
Listeria has been known to plague ready-to-eat deli meats and soft cheeses made with unpasteurized milk, but it鈥檚 popped up in surprising foods in recent years.
Last year, recalled all of its ice cream products after 10 people were sickened by it. One reason listeria differs from other pathogens is that it can grow in cold temperatures.
In 2014, 35 people were sickened by , and officials determined that listeriosis contributed to at least three of the seven deaths reported.
And was behind the largest listeria outbreak in U.S. history which sickened 147 people in 2011 and killed 33.
It鈥檚 time for a freezer check.
CRF has recalled all organic and traditionally grown frozen vegetable and fruit products processed at its Pasco facility since May 2014 and suspended operations there last week.
Check the UPC codes and 鈥淏est By鈥� dates on the vegetable packages in your freezer against .聽If they match, you can return the recalled food to the store for a refund or simply discard it.
Either way, don鈥檛 eat the recalled foods.聽Listeria can be killed with proper cooking, but unless you鈥檙e going to use a thermometer to make sure those聽fruits聽and vegetables reach 165 degrees F, it鈥檚 best not to risk it.
If you did eat them and have symptoms such as fever, stiff neck, confusion, loss of balance and convulsions seek medical care. Sometimes listeriosis symptoms develop up to two months after eating contaminated food, but they usually start within several days.
This story was produced by , which publishes , a service of the .