I have been following this tragic tale since right after Christmas in a series of three posts (1, 2, 3). I was somewhat surprised when Linda Bock of the Worcester Telegram wrote in yesterdays paper that Whittier Farms “voluntarily” stopped production of milk after it had learned that two men over 70 had died, one 87 year old man was still hospitalized and one young woman lost her baby. One wonders how “voluntary” the recall really was? Listeria monocytogenes is a very nasty bug in milk – it clearly can be deadly.

Cornell University, speaking specifically about milk, reported that Listeria monocytogenes can be found in soil and water and has been isolated from a large number of environmental sources. Listeria monocytogenes is destroyed by pasteurization, but if food products are contaminated after pasteurization, Listeria monocytogenes, can grow at refrigerator temperatures.

According to the FDA, Listeria typically causes illness in pregnant adults, newborns, the elderly, and patients with compromised immune systems, but healthy adults and children may also become infected. Symptoms of Listeriosis include flu-like symptoms, fever, muscle aches, stiff neck, headache, septicemia, meningitis, miscarriage, stillbirth, premature delivery, abortion, or death. The CDC reports that in the United States, an estimated 2,500 persons become seriously ill with listeriosis each year. Of these, 500 die. Unfortunatley, is doubtful that fetal deaths are counted in that number.

In June of 2006 researchers at the University of California at Berkeley published disturbing data on “Listeriosis’s path to miscarriage traced to placental infection.” Their research showed that the bacteria may invade the placenta, where – protected from the body’s immune system – they proliferate rapidly before pouring out to infect organs such as the liver and spleen. The illness they cause often results in miscarriage or infection of the fetus.

Listeria infections in the elderly are also common and can be deadly as well. Not surprisingly, inflammation and atrophy of the gastric mucosa escalates with age. Because stomach acids play an important role in limiting the number of bacteria that enter the small intestine, the low gastric acidity common in the elderly, especially those with gastric ulcer disease, increases the likelihood of infection when bacteria is ingested in food or drink. In addition, underlying (co-morbid) conditions contribute to the morbidity and mortality of infection in the elderly. These conditions make the elderly susceptible to certain complications of an infectious diarrheal illness like electrolyte imbalance, dehydration, and shock. And, finally, as people age the immune system is compromised. It leads to an inappropriate, inefficient, and sometimes detrimental immune response, and its effect on health often manifests most apparently during intense stress (e.g., surgery, sepsis, multiple organ failure, malnutrition, dehydration).