By Barbara Young, Editor-In-Chief
Lisa White, research assistant
For years, the beef industry and the U.S. government have battled E. coli O 157:H7 â€” the most insidious among pathogens causing foodborne illnesses, to say nothing of its major threat to the viability of ground beef. This seems a Sisyphean effort given the spate of recalls in 2007, especially the one ultimately forcing Elizabeth, N.J.-based Topps Meat Company LLC, the largest U.S. manufacturer of frozen hamburger, to go out of business. Despite all that has been done to thwart this lethal pathogen since the Jack in the Box outbreak in 1992, the watershed event that placed regulatory and consumer focus on E. coli O157:H7 â€” cases involving contaminated ground beef continue to plague the marketplace.
This report reviews the scientific nature ofE. coli O157: H7 in ground beef along with beef-industry production procedures and best-practice pursuits by select grinders.
E. coli O157:H7 emergesIn his book, “Evolution of Escherichia coli O157: H7 and other Shiga toxin-producingE. colistrains,” Thomas S. Whittam links the emergence of the deadly pathogen to a 1982 outbreak of infectious disease. He writes that the abrupt appearance ofE. coli O157:H7 that year â€” tied to two outbreaks of severe bloody diarrheal syndrome in Oregon and Michigan linked to the consumption hamburgers â€” raised questions as to whether this organism had recently emerged as a pathogen or had always been present and had simply not been recognized. Seeking answers, researchers associated with national laboratories in the United States, Canada and the United Kingdom reviewed their records and their collections ofE. coli samples. They found archivedE. coli O157: H7 strains recovered from the stools of patients in those countries.
Escherichia coli O157:H7 is now a major cause of large-scale epidemics and thousands of sporadic cases of gastrointestinal illnesses in North America, Europe and Japan.
“A critical element in the emergence of this foodborne pathogen was the evolution of acid resistance, an attribute that promotes survival in acidic foods and results in efficient transmission with a low-ineffective dose,” Whittam writes.
Food-safety toolsTo be sure, identifying this relatively new pathogen is an essential first step in finding ways to prevent its harmful impact on human health and the beef products it victimizes. The meat industry, the government and the scientific community are looked to for solutions and remedies. Over the years, scientists and industry manufacturers have pointed to the benefits of various substances and systems including organic acid washes, chlorine dioxide, hot-fat trimming, pathogen detection, steam pasteurization, electron pasteurization, food-grade trisodium phosphate, rapid sanitation control and automated hand-washing among many other. Although much has been done, much more needs to be done, which is not lost on all concerned. “Measures to preventE. coli O157H:7 include lactic acid or acetic acid washes incorporated into specific steps of the process, such as the last step on the harvest floor, or the last step in grinding before packaging,” confirms Shane Dorrian, supervisor, Meat Science Lab, Animal Science Department, University of California, Davis campus. “These preventative measures have been expensive for the beef industry, but have proven to prevent or reduce contamination. The downside is the cost and the change this has on the flavor of the meat.”
Government initiativesRegulations to controlE. coli O157:H7 went into full gear in May of 1993, when then Secretary of Agriculture Mike Espy instructed USDA’s Food Safety and Inspection Service (FSIS) to begin the rulemaking process requiring meat and poultry establishments to develop and maintain a HACCP (hazard analysis critical control point) system. The concept was developed in the 1960s by the Pillsbury Co., while working with NASA (The National Aeronautics and Space Administration) and the U.S. Army to produce a food that could be used under zero gravity conditions by astronauts. The goal involved reaching as close as possible to 100-percent assurance that space-program food be free of bacterial or viral pathogen contamination, among other things.
By 1994,E. coli O157:H7 was declared an adulterant. That same year, FSIS mandated safe-handling labels for raw meat and instituted testing requirements.
A spike in recalls and illnesses blamed onE. coli O157:H7 in 2007, prompted FSIS to adopt new policies to minimize risks associated with the pathogen, including expanded ground-beef pathogen detection testing by more than 75 percent. A more sensitive test for detectingE. coli O157:H7 became available in 2008, which reportedly would likely turn up more positive results than in previous years.
Based on the new policies, when ground beef tests positive forE. coli O157:H7, plants will be under increased scrutiny by FSIS for 120 days thereafter: 16 samples for production rates of 1,000 pounds or more per day and eight for fewer that 1,000 pounds daily. This approach aims to rule out problems in plant processes. FSIS also began operating under new test-and-sample guidelines by changing its selection of plants to sample based on history, volume and past positive samples. Federal inspectors takes 50-60 samples per year from production sites to test forE. coli and Salmonella under HACCP.
Raw material preparationThe essential critical control points in a grinding operation involve the slaughter process and online production.
This phase begins with USDA inspectors’ observation of animals to determine if they are fit for slaughter. Fit animals are stunned by a captive bolt and bled. The removal of various parts follows this step. The carcass is eviscerated after the hide is removed completely. The animal is split down the spine, the spinal cord is removed and the carcass is washed and inspected. Carcasses are coated with an acetic acid spray as a final step.
“This step was only recently enforced by the USDA and FSIS due to recalls of beef contaminated with O157:H7,” Dorrian reports.
The stunning and bleeding process must be executed perfectly, he emphasizes, as the USDA inspector is empowered to file a non-compliance citation concerning the animal handling/humane slaughter step otherwise. Moreover, hides must also be removed perfectly, leaving behind no residual hair or fecal matter.
“The carcass will not move down the line until the inspector OKs the post-hide removal critical control point,” Dorrian reports.
Carcasses should chill a minimum of 24 hours in a high-air-velocity cooler at 38°F. The first essential step concerning plants that receive raw materials such as beef trimmings from other providers is to ensure that the temperature of the incoming material is below 45°F.
Any product received that is found to exceed this temperature shall be considered to possibly harbor bacteria, and must not be used, confirms Dorrian, adding that individual plants employ different standards for receiving materials, but the most common approach is to check the temperature and ensure that all vacuum-packed materials are still sealed.
Often the chuck, between the shoulder-blade and the neck, is used for stew meat or trimmings for ground beef. As Dorrian notes, however, any part of the carcass can be boned out to make ground beef. Jack in the Box Inc. uses the sirloin for its ground beef, for example.
A recent innovation in ground beef calls for using better wholesale cuts of beef, such as ground sirloin, Dorrian notes. “This simply enhances flavor and tenderness,” he adds. “Texture is very important for flavor and tenderness. A finer grind will be more palatable, but some processors have chosen to use a coarse grind to preserve the beef flavor and increase texture.”
Production toolsMetal detection is essential technology for grinders. Metal detectors, capable of removing foreign metal objects to prevent them from hitting the grinder or knife, are built into grinding systems. “That’s the utopia,” surmises Byron Williams of Alabama A&M University. “There are even devices that can be attached to grinders to remove bone or other contaminants. Inevitably small pieces of bone make it into the grinders. The name of the game is to remove as much contamination before getting into the grinder. Many facilities even have metal detection systems downstream post-packaging to ensure the integrity of the ground beef.”
Trevor Caviness, Caviness Beef Packing Ltd., Hereford, Texas, says necessary plant floor equipment for ground beef production includes a combo dumper, product inspection belt, first grinder, augers that take boneless beef to blender, augers taking product from blender to second grinder, auger going to pump, final packaging equipment, blender, second grinder and pump.