The media is finally catching on to the outbreak of Listeriosis associated with cantaloupes that commenced on July 31, 2011. As of September 26, CDC reports that there have been a total of 72 persons from 18 states infected with the four outbreak-associated strains of Listeria monocytogenes. There have also been 13 deaths. Fortunately for us, no cases have been reported in Ohio.
So what is Listeria monocytogenes, what are the symptoms, and why can it be so dangerous? Listeria monocytogenes is a Gram-positive rod-shaped bacterium. It is commonly found in soil and water and typically infects foods of animal origin like meats and dairy products. The bacteria can be easily killed by cooking and pasteurization, but there are a lot of processed and raw foods where Listeria will thrive. Particular food favorites include deli meats, hot dogs, raw milk and cheeses. It’s unusual for produce to be a source of an outbreak but it has happened in the past. Looking at past stats, on average from 1998-2008, there have been 2.4 outbreaks per year reported to CDC. The largest outbreak occurred in 2002, when 54 illnesses, 8 deaths, and 3 fetal deaths in 9 states were found to be associated with consumption of contaminated turkey deli meat. Now the current outbreak seems to be associated with contaminated cantaloupes from a particular farm in Colorado.
Listeriosis can affect anybody eating contaminated product but the most susceptible are older adults, pregnant women, newborns, and adults with weakened immune systems. Usually symptoms will be mild like fever, myalgias, diarrhea and other GI complaints. However, for the elderly and the immunocompromised there can be septicemia and meningoencephalitis. For the pregnant female, manifestations can include miscarriage, stillbirth, premature delivery, or neonatal sepsis.
The key to not getting Listeriosis is prevention. Rinse raw produce, such as fruits and vegetables, thoroughly under running tap water before eating. Dry the produce with a clean cloth or paper towel before cutting them up. Thoroughly cook raw meat and poultry. Heat hot dogs, deli meats, and cold cuts until they are steaming hot just before serving. Avoid drinking raw (unpasteurized) milk. Also don’t eat fresh soft cheeses that have unpasteurized milk in them, like queso fresco. Finally, how many of us check the temperatures of th refrigerator? Make sure that your refrigerator is at or below 40 degrees F and your freezer is at or below 0 degrees F. Use a refrigerator thermometer for accuracy.
However, should a person contract the disease, the mainstay therapy continues to be antibiotics like ampicillin, trimethoprim-sulfamethoxazole and gentamicin.