EXTENSION REPORT

The Many Guises of a Deadly Pathogen

               Whoever would have imagined that a pathogen typically linked with undercooked ground beef would turn up in bags of raw spinach?  No doubt, very few.  Whatever the case, this unsettling discovery drives home the fact that E. coli 0157:H7 can show up in the most unlikely of places and under many different guises.

What accounts for occasional outbreaks of the pathogens in raw vegetables?   Lots of things, according to Dr. Jean Weese, an Alabama Cooperative Extension System food scientist and Auburn University professor of nutrition and food science.   E. coli can be spread from water used to irrigate produce in the field, especially if this water is drawn from surface water in which livestock or wildlife have defecated or waded.  Even products grown in soil where wild animals have defecated can harbor traces of E. coli and other pathogens.

Organically grown produce --- considered the most pristine of products by many Americans --- may be susceptible to E. coli in cases where manure is being used as a fertilizer, Weese says.  “When you raise things in manure, you’re going to be exposed to bacteria,” Weese says.  “E. coli lives in the intestines of animals, and there is always the risk it’s going to be passed along to produce.”

For a long time, many food scientists assumed that pathogens associated with animal waste were present only on the exterior of organically grown produces.  More recently, though, studies have shown that these pathogens actually can turn up inside the produce --- a fact uncovered in Weese’s own research.

In a study conducted with lettuce plants, Weese learned that potentially deadly E.coli pathogens from tainted soil can be taken up into the stem of plants only a few days after planting. This finding accounts for why Weese personally has taken a hard line on the routine consumption of raw, organically grown produce, especially in cases where children are involved.  “My recommendation is not to feed any child age 6 or younger raw, organically grown produce,” she says.  According to Weese, it is the reason why consumers must take responsibility for their own safety, especially when preparing raw foods in the home. 

The operative advice is to wash repeatedly, she says.  Unfortunately, this won’t help with organically grown produce, though it will be effective against other produce.  Indeed, every time you wash produce, you’re removing potentially harmful pathogens --- the reason why she advises washing produce, allowing it to drain and repeating the cycle once or twice.  Soaking, on the other hand, is self-defeating because it gives the bacteria a chance to get into every nook and cranny, which makes them even harder to remove.

Diligent washing is especially important within households where children, elderly and people with compromised immune systems live --- even people suffering from colds.  All of them are more susceptible to the pathogen’s effects.  E. coli O157:H7 causes diarrhea, often with bloody stools. Although most healthy adults can recover completely within a week, some people can develop a form of kidney failure called hemolytic uremic syndrome. This syndrome is most likely to occur in young children and the elderly, and it can lead to serious kidney damage and even death.

Most Americans first became acquainted with this deadly pathogen in 1993, when several people, mostly children, died from exposure to the pathogen after consuming undercooked ground beef at a chain restaurant in the Pacific Northwest. Hundreds of others survived the ordeal after enduring days of excruciatingly severe nausea, cramping and bloody diarrhea.  For more information on this and other Food Safety concerns please contact Amelia McGrew at (251) 574-8445.

Email address: mcgreaj@auburn.edu
Phone: (251) 574-8445

Issued in furtherance of Cooperative Extension work in agriculture and home economics, Acts of May 8 and June 30, 1914, and other related acts, in cooperation with the U.S. Department of Agriculture. The Alabama Cooperative Extension System (Alabama A&M University and Auburn University) offers educational programs, materials, and equal opportunity employment to all people without regard to race, color, national origin, religion, sex, age, veteran status, or disability.