March 23, 2010
by Bryan Salvage
CHICAGO — The beef industry continues to explore solutions to the threat posed to the food supply by E. coli O157:H7. Developing technologies to detect and control the growth of the pathogen was the topic of discussion at a presentation during the North American Meat Processors Association’s 2010 Meat Industry Management Conference, held last weekend in Chicago.
Eliminating a microbial pathogen from a raw product is a daunting task, said Dr. James Marsden, senior science advisor for N.A.M.P. and Regent’s Distinguished Professor, Kansas State University.
Although challenges still exist, progress has been made since then and the beef industry can do more in battling this pathogen in the future.
One major challenge for beef processors and grinders is pathogens enter their process in raw materials. “Processors have to rely on upstream interventions, testing of trimmings and the few available processing interventions to reduce their risk,” Dr. Marsden said.
Recent industry concerns include an increase in incidence of E. coli O157:H7 in raw ground beef and an increase in foodborne illnesses associated with beef.
In the quest to control of E. coli O157:H7, recent developments include:
* U.S.D.A conditional approval of a vaccine for cattle—Epitopix LLC.
* Development of a potentially significant new pre-harvest intervention—a bacteriophage that is specific for E. coli O157:H7.
* Research on additional pre-harvest interventions, including sodium chlorate and probiotics.
* Improved systems for controlling environmental vectors of contamination during and after the slaughter process, including the Environmental Management System (E.M.S.).
* Improved slaughter interventions—i.e., peracetic acid and bromous acid.
* Post-chill carcass contamination technologies—carcass pasteurization.
* Technologies to prevent recontamination of clean carcasses from environmental vectors—i.e., drains, air, holding pens.
* High hydrostatic pressure for treatment of beef trimmings.
* U.V./advanced oxidation technologies for subprimals and trimmings.
* Development of chemical antimicrobial treatments for processing applications.
* Improved sampling and testing systems for trimmings—N-60.
* Combining effective interventions to achieve a >3 log reduction on trimmings.
Research on vaccines has shown a 98% reduction of E. coli O157 fecal contamination, Dr. Marsden said. “A vaccine for cattle would also reduce environmental sources of E. coli O157:H7 that have been implicated in foodborne disease outbreaks from lettuce, spinach and other non-meat foods,” he added.
Bacteriophage is an E. coli O157: H7-specific phage that is sprayed on the hides of cattle before slaughter. “Cost is approximately 75 cents to 95 cents per head. It is already being used at some commercial slaughter plants and the results are impressive,” Dr. Marsden relayed.
Although sodium chlorate produces a cytotoxic effect on E. coli O157:H7 and is relatively inexpensive, it is not yet approved. Meanwhile probiotics are based on competitive exclusion. Research is underway on probiotics specific for E. coli O157:H7.
Carcass interventions are important in battling this pathogen and include washing live cattle prior to slaughter, high-pressure washing before hide removal, chemical and thermal carcass pasteurization technologies, improved environmental control during the slaughter process—ozone and vaporized hydrogen peroxide based technologies; carcass spacing technologies to facilitate proper cooling and reduce opportunity for outgrowth; and carcass pasteurization—advanced oxidation and chemical antimicrobials, Dr. Marsden said.
In conclusion, Dr. Marsden presented the following blueprint for an integrated process to successfully battle E. coli O157:H7:
* Vaccine or bacteriophage—Reduces incidence of E. coli O157:H7 in cattle.
* Washing live cattle prior to slaughter.
* Enhanced slaughter interventions.
* Post-chill carcass pasteurization.
* Technologies to reduce surface contamination on trimmings prior to grinding—U.V., P.A.A., bromous acid, Sanova.
* N-60 testing. For trimmings destined for ground beef and finished product testing to verify process control.
* Pasteurization using high-hydrostatic pressure or electron-beam treatment.
* Validated cooking procedures in restaurants.
* Consumer education on safe food handling and cooking.
“The net effect of this integrated process is a major reduction in risk associated with E. coli O157:H7 in beef products,” Dr. Marsden concluded.