Fresh concerns over possible Listeria contamination has prompted producer River Ranch Fresh Foods to issue a voluntary nation-wide recall for its bagged salad.
The bacteria Listeria monocytogenes can cause serious, potentially fatal infections in children, the elderly and others with weakened immune systems. A 28-state outbreak in 2011 - one of the deadliest on record - claimed 30 lives with 146 confirmed cases of the illness.
Routine random tests conducted by the Food & Drug Administration revealed the potential for contamination. Affected products are packaged under the brand names of River Ranch, Farm Stand, Hy-Vee, Marketside, Shurfresh, and The Farmer's Market.
In healthy adults, the bacteria can cause flu-like symptoms including fever, severe headache, stiffness, nausea, abdominal pain and diarrhea.
Thus far, no one has been reported sick in connection with any potentially contaminated salad, according to the company's official press release.