Consumer Reports found that samples of some popular pre-washed greens sold in stores including lettuce, spinach and kale were tainted with a potentially deadly bacteria.
The new report tested 284 samples of fresh greens, many that were purchased at several common grocery store chains including Acme, Costco, Hannaford and Whole foods.
The report found that six samples were tainted with Listeria monocytogenes, a potentially life-threatening bacteria that causes foodborne illness, and the worst part of all: The bacteria can grow under refrigerator temperatures.
The report notes that these contaminated samples were pre-washed and unbagged greens and were purchased between June 3 and June 19, 2019 in Connecticut, New Jersey and New York.
According to the Centers for Disease Control and Prevention, an estimated 1,600 people get listeriosis each year resulting in about 260 deaths.
Some symptoms of listeria infection are headache, stiff neck, confusion, loss of balance and convulsions as well as fever and muscle aches.
Pregnant women and newborns, adults aged 65 or older, and people with weakened immune systems are most at risk, according to the CDC.
Of the six samples tainted with Listeria monocytogenes, Consumer Reports said that one had a strain genetically linked to at least two cases of listeriosis.
Consumer Reports also noted that their study is too small to draw any conclusions about a specific brand or retailer, but it is intended to highlight that more is needed to ensure consumer safety.
While the report links common everyday greens bought at various retailers, the CDC says that listeria outbreaks are often related to dairy products as well, tracing recent outbreaks to soft cheeses and ice cream.