991147 Deadly E. Coli Bug May Affect Half of CattleNovember 15, 1999
Washington - A deadly strain of E. coli bacteria is far more common in U.S. cattle than previously thought, and may be found in half the animals that are made into ground beef, steaks and other cuts, a senior U.S. Agriculture Department official said.
The surprisingly high rate of E. coli 0157:H7, detected by more sensitive testing techniques used since September, has prompted the USDA to take the unusual step of re-evaluating how it regulates the foodborne disease.
The bacteria can cause kidney failure and death among children or the elderly who eat contaminated ground beef.
But among cattle, E. coli 0157:H7 lives harmlessly in the digestive tract. The bug migrates when animals are slaughtered and skinned, moving from internal organs and hides to flesh.
Tom Billy, administrator of the USDA's Food Safety and Inspection Service, said in an interview that agency scientists were still analyzing data but decided to alert the industry about the unexpected preliminary results.
USDA regulations to protect consumers from E. coli 0157:H7 contamination were based on 1994 data showing the bug occurred in one of every 2,000 or so carcasses at the slaughter plant.
The prevalence could be much more common and as high as one in every two carcasses, Billy said. If that's true, it changes significantly the options available to us to achieve the zero tolerance.
USDA regulations allow zero tolerance of E. coli 0157:H7. If tests detect the pathogen in raw ground beef, that batch is considered adulterated and is usually destroyed. Companies can process the meat at high temperatures to kill the bacteria, then use it in cooked foods such as canned chili.
We are not changing the zero tolerance policy. That will remain in effect. That will not change, he said.
The USDA is drafting some options that may include changes in testing procedures, and will publish them next month. A public hearing will be held in mid-January, Billy said.
The new data was criticized as misleading by cattlemen.
There is no evidence the prevalence of this organism has changed at all since we began studying it in the early 1990s, said Gary Weber of the National Cattlemens Beef Association.
The USDA data reflects only whether cattle have been exposed to the bug at some point in their lives -- not that they are carrying it at the time of slaughter, Weber said. Actual infection rates are less than one-half percent of cows, based on testing by meat grinders and processors, he said.
The new data also raises the issue of whether farmers and ranchers need to do more to prevent E. coli in their herds.
The bacteria is found more often on the hides of feedlot cattle, the USDA said. Feedlot cattle are typically fattened in a confined area just before going to slaughter.
The animals spread E. coli 0157:H7 by defecating and drooling in shared water troughs.
Consumer groups say on-farm prevention is essential.
We'd like to see development of some kind of vaccine or competitive exclusion product for cattle that will eliminate this strain of bacteria from the gut of the animals, said Caroline Smith DeWaal, a food safety expert with the Center for Science in the Public Interest.
The U.S. meat industry is also examining the issue.
The American Meat Institute, an industry trade group, has funded research to measure how much E. coli is left on an animal hide after slaughter. The researchers are also trying to determine whether various chemical dips, steam vacuuming or other treatments of hides are best to kill the bacteria.
With E. coli more common in raw meat, processors are likely to embrace irradiation technology that can kill the bacteria.
Several companies are looking very hard at irradiation right now, said Mike Doyle, a University of Georgia researcher. The economics are an important factor. How much are we willing to pay for ground beef, and how much are we willing to throw out as adulterated?
The USDA's long-delayed regulations for irradiation use in plants will be issued by the end of December, Billy said.
The USDA monitors E. coli 0157:H7 in ground beef by taking 8,000 samples annually at slaughter plants and grocery stores.
A recent outbreak of the bug at a New York fair killed an elderly man and a three-year-old girl, and sickened more than 600 others. Investigators have theorized a water well may have been contaminated by nearby dairy cow barns.
Nationwide, an estimated 52 Americans die annually from from E. coli 0157:H7 and 60,000 others fall ill from the bug.