The vegetables may be contaminated withListeria monocytogenes, a bacterium which can cause serious and sometimes fatal infections in young children, the elderly, pregnant women, and others with weakened immune systems. Symptoms include high fever, severe headache, stiffness, nausea, abdominal pain, and diarrhea; Listeria can cause miscarriages, stillbirths, and fetal infection among pregnant women. No illnesses have yet been reported.