What is Listeria?

From www.about-listeria.com


Listeria monocytogenes (Listeria) is a pathogenic (disease-causing) bacterium that is food borne and causes an illness called listeriosis. It is frequently overlooked as a possible cause of illness due to its unique growth capabilities. First, it is somewhat difficult for laboratories to grow, and when they do so, Listeria can be confused with common harmless contaminants and disregarded. Second, most bacteria grow poorly when temperatures fall below 40°F, while Listeria survives in temperatures from below freezing (20°F) to body temperature and it grows best at 0°F to 50°F, including the temperature range that we use for refrigeration. As a result, Listeria may be transmitted in ready-to-eat foods that have been kept properly refrigerated. Its ability to grow in such diverse environments is just one of the many challenges presented by this dangerous bacterium.  It is estimated that Listeria causes approximately 1,600 cases of listeriosis annually, resulting in 415 deaths.


IN THE SANTA CRUZ SENTINEL

Monterey Mushrooms issues recall in several Northeastern states

By TOM RAGAN

        WATSONVILLE — Monterey Mushrooms is recalling 10,000 cases of fresh mushrooms because they may be contaminated with a sometimes-fatal bacteria, the Watsonville-based company announced.  The sliced white and Baby Bella mushrooms were distributed at retail stores and produce markets in Maryland, New Jersey, New York, North Carolina, Ohio, Pennsylvania and Virginia, according to Lisa Bridges, a spokeswoman at the company's marketing office in Knoxville, Tenn.

Listeria monocytogenes
(Listeria) is a foodborne disease-causing bacteria; the disease is called listeriosis. Listeria can invade the body through a normal and intact gastrointestinal tract. Once in the body, Listeria can travel through the blood stream but the bacteria are often found inside cells. Listeria also produces toxins that damage cells. Listeria invades and grows best in the central nervous system among immune compromised persons, causing meningitis and/or encephalitis (brain infection). In pregnant women, the fetus can become infected, leading to spontaneous abortion, stillbirths, or sepsis (blood infection) in infancy.

Approximately 2,500 cases of listeriosis are estimated to occur in the U.S. each year. About 200 in every 1000 cases result in death. Certain groups of individuals are at greater risk for listeriosis, including pregnant women (and their unborn children) and immunocompromised persons. Among infants, listeriosis occurs when the infection is transmitted from the mother, either through the placenta or during the birthing process. These host factors, along with the amount of bacteria ingested and the virulence of the strain, determine the risk of disease. Human cases of listeriosis are, for the most part, sporadic and treatable. Nonetheless, Listeria remains an important threat to public health, especially among those most susceptible to this disease.  For more information on Listeria at Marler Clark, see http://www.marlerclark.com/news-listeria.htm

From the National Science Foundation

Listeria Monocytogenes L. monocytogenes -- a rod-shaped bacterium that moves by means of flagella -- is a carrier of listeriosis, a general name given to the group of disorders caused by the organism, such as meningitis and encephalitis. This image was taken during research performed in the lab of professor Daniel Portnoy, Department of Molecular and Cell Biology, University of California, Berkeley. Dr. Portnoy's research focuses on understanding the molecular and cellular basis of microbial pathogenesis and the mechanisms used by the host to defend against infection. Specifically, the lab is focused on the interaction of the facultative intracellular bacterial pathogen L. monocytogenes and mammalian cells. This fascinating microorganism is able to enter cells, escape from a phagosome and grow rapidly in the cytosol. By exploiting a host system of actin-based motility, the bacteria move through the cytosol to the cell membrane and into pseudopod-like projections (listeriopods) that are ingested by neighboring cells. This mechanism allows pathogens to spread from one cell to another without ever leaving the host cytoplasm thereby avoiding the immune response. (Date of Image: 2000)

Credit: Justin Skoble and Dan Portnoy

Fresh mushrooms recalled because of possible contamination

Associated PressFriday, September 8, 2006 5:13 AMBALTIMORE -- A mushroom grower is recalling about 10,000 cases of fresh sliced white and baby portobello mushrooms because they may be contaminated with an organism that can cause fatal infections in some people, the company announced yesterday.Monterey Mushrooms of Watsonville, Calif. said the mushrooms were distributed from its plant in Temple, Pa., to Maryland, New Jersey, New York, North Carolina, Ohio, Pennsylvania and Virginia. The product was sold in 4 ounce, 6 ounce, 8 ounce, and 16 ounce foam containers and 10 ounce plastic bags with code dates 237 through 247.Monterey was notified of a positive test result for Listeria monocytogenes on its 6 ounce sliced Baby Bella product during a random product sampling by the Ohio State Department of Agriculture.Listeria can cause serious, sometimes fatal infections in young children, frail or elderly people, and others with weakened immune systems. Listeria infection can cause miscarriages and stillbirths among pregnant women. Healthy people may suffer short-term symptoms such as high fever, severe headache, stiffness, nausea, abdominal pain and diarrhea.No illnesses have been reported, Monterey said.Consumers who purchased the mushrooms are urged to return them to the place of purchase for a full refund.