ALABAMA A&M and AUBURN UNIVERSITIES

AUBURN, MAY 21---There’s been quite a bit of hysteria over listeria recently – and for good reason: while there’s plenty of reason to be concerned about the pathogen, no one is quite sure what to do about it.

Until recently, outbreaks of listeriosis had been rare, and knowledge about the pathogen had been limited to a handful of food scientists and others in the academic community.
Then, in December 1998, the public was acquainted with the pathogen after a number of deaths from listeriosis prompted the recall of 45 million pounds of hot dogs and processed luncheon meats.

Unlike other well-known, food-related pathogens, such as E.coli 0157:H7, listeria can be found virtually everywhere in the environment: in the air, in the ground and even on people. While the majority of listeria is harmless, one especially virulent strain, listeria monocytogenes, can cause a variety of problems resulting in death in some cases.

“It can cause things as drastic as miscarriages, birth defects and even death among people who suffer from immune deficiencies, such as AIDS sufferers,” says Dr. Jean Weese, an Alabama Cooperative Extension System food scientist.  “Miscarriages are the most common effect caused from exposure to listeria but, tragically, this often occurs without many women knowing the cause.”

Another characteristic distinguishing listeria from other food pathogens is it’s extremely cold tolerant.

“This should be of special concern to consumers since this increases the likelihood of cross contamination, which occurs when contaminated products come in contact with uncontaminated ones,” Weese says.

Also, since listeria is airborne, meat remaining uncooked throughout the processing cycle is especially vulnerable to exposure.  This is especially true for cold cuts such as luncheon meats.

“The irony to all this is listeria can be easily eliminated through cooking,” Weese says.  “But since luncheon meats typically aren’t cooked prior to consumption, they are a major source of contamination.”

In the aftermath of last December’s tragedy, state and federal authorities are taking steps to reduce risks of listeria exposure, especially in processing plants. A new DNA test already has been adopted that will allow federal authorities to trace listeria outbreaks in processed foods to their ultimate source.

State and federal authorities also are coordinating efforts so information about listeria outbreaks can be processed more quickly.

Regulators also are considering making microbial testing mandatory in processing plants, requiring labeling for all cold cuts and franks, and spearheading a consumer-education program.

Processors also are exploring new techniques for sanitizing plants.  Some experts suspect sanitation breakdowns may be one of the root causes of listeria-related problems.
Weese, in her dual capacity as an Auburn University researcher, is pursuing several research grants to explore different sanitizing methods.

“We’re already looking at several chemical washes that may be effective in reducing the growth of listeria,” Weese says.  “There are lots of people looking at ways to control listeria.  The problem is  there’s no sure solution at this point.”

One such “solution” could be the myriad of chemicals and gases given off as flavor and odors in some plants, many of which are deadly to bacteria, Weese says.

Weese also has received some funding from the American Meat Institute to explore how irradiation can be used to kill the pathogen in cold cuts.

SOURCE:  DR. JEAN WEESE, Extension food scientist, Alabama Cooperative Extension System, (334) 844-3269.