Auburn, Feb. 4---Food safety experts have described it as "one tough bug."

Listeria, as the "bug" is commonly called, is a pathogen that is far more pervasive than other potentially deadly pathogens, such as E.coli O157:H7 and Salmonella.

"One thing that distinguishes Listeria from better-known disease-causing agents, such as E.coli and Salmonella, is that it can be found practically everywhere – in the air, on the ground, in water, in soil and even on people," says Dr. Jean Weese, an Alabama Cooperative Extension System food scientist.

Scientists have known this for a long time – about 60 years, in fact – but even now, they are not quite sure what to do about Listeria.

Indeed, until a few years ago, knowledge of the pathogen was limited largely to Weese and other experts within the food science community – not surprising, since outbreaks associated with the pathogen were rare.

Then, beginning in the 1980s, Listeria began leaving its calling card. In December, 1998, for example, several deaths from listeriosis prompted the recall of more than 45-million pounds of hot dogs and processed luncheon meats.

The pervasive nature of Listeria is a special concern to meat processors because of the various ways it can get into a plant, such as on the hooves, carcass and intestines of livestock animals.

Also, compared with other foodborne pathogens, Listeria is far more cold tolerant, which can increase the risk of cross-contamination while food is being prepared.

"This should be of special concern to consumers since this increases the risk of foods being contaminated by other food or from unhygienic handling during meal preparation," Weese says.

This, she says, explains why cold-cut meats are a major concern, since there is a greater likelihood these products may harbor Listeria by the time they reach the kitchen.

Still, even despite these risks, listeriosis poses little threat to the general population, and the likelihood of an individual developing Listeria after consuming contaminated food remains very small. On the other hand, for people with comprised immune systems or other medical conditions, the disease can be fatal.

Those at highest risk include AIDS, chemotherapy, and kidney disease patients, diabetes sufferers, pregnant women, infants and the elderly.

AIDS patients are especially prone to develop listeriosis. Studies have shown they are 300 times more likely to get the disease compared with people with normal immune systems.

Pregnant women are also an especially vulnerable group.

"Pregnant women need to be especially cautious about consuming foods that are associated with a high risk of listeriosis," Weese says, "because the disease can cause intrauterine infections of the fetus that can lead to spontaneous abortions and even stillbirth."

Many scientists, in fact, now believe the repeated miscarriages and infant deaths associated with Queen Anne’s pregnancies may have been caused by Listeria infections.

Flulike symptoms such as fever, muscle aches, nausea, diarrhea or a stiff neck are common symptoms associated with listeriosis.

While healthy people usually recover quickly and fully from exposure to Listeria, individuals with weakened immune systems often are not so lucky.

"With exposure, you’re not going to get the kidney damage and related complications associated with E.coli O157:H7," Weese says. "On the other hand, if you fail to seek treatment for listeriosis, you can develop a form of meningitis. You may even develop arthritic symptoms that linger for a lifetime."

The Centers for Disease Control reports that approximately 1,500 people become seriously ill from exposure to Listeria every year, while roughly 425 people eventually die from listeriosis. Listeria can be prevented by thoroughly cooking meats and washing raw vegetables before consuming them

People at high risk should be especially wary of foods such as smoked fish and mussels, oysters or raw seafood such as sashimi or sushi.

This also includes prepared or stored salads, such as coleslaw, and pre-cooked meat products, such as deli meats and pate, that require no additional cooking or heating before serving.