A California producer has issued a recall for bagged lettuces after listeria was found during a routine check.
The lettuces were distributed nationwide and under the brand names River Ranch, Farm Stand, Hy-Vee, Marketside, Shurfresh and The Farmer's Market.
Recalled bags have either "Best By" dates between 12MAY2012 – 22MAY2012 or Julian dates between 116 – 125.
Listeria monocytogenes can cause potentially fatal infections in the young, old, infirm and those with weakened immune systems. Pregnant women are especially vulnerable, as listeria can cause stillbirths and miscarriages.
No illnesses have yet been linked to this outbreak.