Food Safety Magazine February 2023

The story of the 1992–1993 Jack in the Box outbreak is well documented, but how E. coli O157:H7 first showed up on the radar is less known

By Andrew Kesler, Corporate Director of Supplier Compliance 

Thirty years ago in January saw the beginning of what became known as “The Crisis” at Jack in the Box restaurants, when hundreds of customers became seriously ill after eating hamburgers containing Escherichia coli O157:H7. This illness outbreak—at the time, the largest in U.S. history—would claim four young lives, leave many others with lifelong health impairments, sicken over 700 people, and nearly ruin Foodmaker Inc., the parent company of Jack in the Box.

Two years prior to this outbreak, in 1991, I spent my first Thanksgiving away from home at a Jack in the Box restaurant in Lompoc, California. At the time, I had no idea that Jack in the Box would become a defining part of my career in food safety or that I would even have a career in “food safety.” I would later join the quality assurance team at Jack in the Box, led by the late Dr. David Theno, a prominent food safety and process control consultant who was hired by Foodmaker to figure out why the outbreak occurred and to put systems in place to prevent another one from happening.

The story of this seminal illness outbreak is well documented, but how E. coli O157:H7, the deadly organism responsible for the 1992–1993 Jack in the Box outbreak, first showed up on the radar is less known. The story begins a decade earlier, in 1982, with another, much larger, fast food restaurant chain. It is important to examine this earlier outbreak (which was technically two outbreaks) to understand why the aftermath of the Jack in the Box outbreak was much different, as well as how it propelled huge changes in the meat industry and within large restaurant chains. The entire food industry became much stronger because of Dave Theno’s fundamental philosophy that there should be no competitive advantage in ensuring food safety.

The Centers for Disease Control and Prevention’s “We Were There” series offers a segment on E. coli O157:H7. It briefly discusses the 1982 outbreaks and the scientific work that followed, and it reviews the Jack in the Box outbreak and its impact at length. It is told from the perspective of the regulators and their conclusions on how this outbreak changed the industry. This article summarizes my personal observations based on over a decade of working at Jack in the Box and almost three decades of experience in the industry. Many of the projects I have worked on came about as a direct result of corrective actions and regulations borne from our collective journey with pathogenic E. coli.

Forty Years Ago

The 1982 E. coli outbreaks are not well known or discussed in nearly any historical account of E. coli O157:H7. The name of the restaurant chain involved is rarely associated with the outbreaks in the same way that Jack in the Box is forever linked to the 1992–1993 outbreak. In 2012, Bill Marler, the attorney who represented many of the victims of the Jack in the Box outbreak asked (rhetorically) on his blog: “What if, in 1982, McDonald’s had been named as the source of the 47 sickened by E. coli O157:H7-tainted hamburger in two states?”1 Would the Jack in the Box outbreak have occurred ten years later?” That is a nearly impossible question to answer, but the 1982 outbreaks did not make the national news, nor did they prompt the collective changes in food safety spurred by the Jack in the Box outbreak, in which four young children died.

On March 24, 1983, the New England Journal of Medicine published the article, “Hemorrhagic Colitis Associated with a Rare Escherichia Coli Serotype.”2 The article summarizes the investigation results from two outbreaks, one in Michigan and one in Oregon, which sickened “at least” 47 people in early 1982. The common food in the outbreaks was hamburger with three common ingredients from a single fast-food chain—beef patty, pickles, and rehydrated onions. While the report did not name the restaurant associated with the outbreak, only one fast-food chain at the time had restaurants in both Michigan and Oregon, cooked hamburger patties on flat grills, and used rehydrated onions.

One brief news article about the outbreaks, probably buried on the back pages of The Washington Post, was published on October 9, 1982. It linked McDonald’s to what was then a “rare intestinal illness… which may be linked to undercooked hamburgers.” Cristine Russell, writing for The Washington Post, remarked that the McDonald’s home office in Oak Brook, Illinois “…contended that the link with its hamburgers might be a statistical anomaly and said that the company’s required cooking procedures ‘ensure product safety.'”3 In defense, McDonald’s Vice Chairman, Edward Schmitt, made remarks about the small number of illnesses as “isolated incidents.” He further remarked that the chain had served almost two billion burgers since the illnesses occurred. In this context, with little known about E. coli‘s ability to make humans sick (and kill them), it is understandable to characterize this event as an “anomaly.”

Although McDonald’s publicly declared the outbreaks to be an anomaly, the company took action to investigate the microorganism and new cooking technologies to combat it—a very early example of large foodservice companies sponsoring and promoting significant food safety research in partnership with government and industry. After the 1982 outbreaks, McDonald’s hired then-University of Wisconsin microbiology professor Dr. Michael Doyle, who recommended new clamshell grills (among other actions) that would cook patties simultaneously on both sides and not open until the cook time was completed. The cook times and temperatures were researched thoroughly to ensure that harmful microorganisms were destroyed during the cooking process. Side note: I was an assistant manager at a McDonald’s restaurant in the late 1980s and helped install the new clamshell grills. It would be more than 30 years before I connected the dots behind why we switched to this equipment. At the time, I assumed it was to cook the patties faster and increase “speed of service.”

Still, the 1982 incident remained an obscure, back-page news article, and the controls implemented to ensure product safety were intended to solve the problem primarily through control steps in the restaurants. It would be an entirely different outcome ten years later, after four children died from undercooked hamburgers served by the nation’s fifth-largest fast-food chain. The news went national with the Jack in the Box logo all over it, which got the attention of the public, the industry, the regulators, and, most importantly, Washington, D.C. There was no keeping the Jack inside this box. 

Thirty Years Ago

Dave Theno told the story many times. To remind him of whom he actually worked for, regardless of the company logo on his paycheck, he carried in his wallet a picture of six-year-old Lauren Rudolph. He often showed the picture to people when explaining why he recommended a particular course of action to protect public health. “Lauren is who we are protecting. Lauren, and the children she represents, is who I report to,” he would say. She was the first victim of the Jack in the Box outbreak, and Dave got to know her family well through the ordeal.

The story of “The Crisis,” as it came to be known at Foodmaker, was expertly researched and told by Jeff Benedict in his 2011 book, Poisoned.4 The major parts of the outbreak had been explained before, but what the uncomfortable narrative teaches is how hemolytic uremic syndrome (HUS), an infection of the digestive tract caused by E. coli O157:H7, destroys the red blood cells in the body, causing extreme pain in the kidneys and other organs as they begin to fail. That such young children could die such painful deaths—just from eating a hamburger—was unimaginable to me. Riley Detwiler, one of the four young victims, did not even eat a hamburger. He merely came into contact with another child at a daycare center who had eaten contaminated beef—a testament to how virulent E. coli O157:H7 can be, even spreading through cross-contact among people.

By early 1993, the outbreak had become national news, with a newly elected president calling the parents of the victims and promising to do more to ensure safe food. Regulators and industry had become more willing to accept changes in how food was inspected. The relentless national media attention, combined with civil litigation resulting in multimillion-dollar settlements for the victims, created an environment that demanded significant change—on the part of industry and regulators.

The course of action Dave embarked on when he arrived at Foodmaker—first as a consultant, and then full-time as a Vice President—was to determine where in the process, from farm to fork, controls could be implemented and measured to ensure safe hamburgers. His goal was to give the leadership team specific metrics to monitor as an indicator of the health of their food safety program, so that they could take immediate action if the system went out of control.

Dave realized that fully cooking the hamburgers solved only half the problem. Knowing that the pathogenic organism can be transferred through bare-hand contact required an additional mitigation step to solve the other half of the problem. He implemented a “no bare-hand contact” rule with raw hamburger patties, which was unheard of at the time for any large restaurant chain. Training grill employees to use tongs, rather than their hands, to separate the frozen patties and then place them on the grill was no small feat, especially when it was common to place up to 12 patties on the grill at the same time.

In the restaurants, Dave implemented a mandatory “final flip and visual check” of each patty before pulling it off the grill to make sure the patty was not pink after the scheduled cooking time. (Unlike McDonald’s, which had plenty of cash to invest in clamshell grills, Foodmaker did not have such capital available at the time. It was uncertain if the company would even survive.) The combination of checking each patty and monitoring the temperatures of the grill surface and the internal patty several times each day ensured the cooking process was continuously in control.

“No bare-hand contact” and the “final flip and visual check” became the fundamental critical control points in what was the first HACCP program created for a restaurant; and these two steps were observed and documented by the restaurant’s management several times throughout the day. Procedures were also implemented to verify the cooking processes by measuring the temperature of the cooked patties several times per day. This became another critical control point in the restaurant HACCP program. Compliance with these steps in the process, along with many others, was now measured and became a metric for Jack in the Box’s operations teams to monitor the health of their restaurant chain’s food safety system.

Dave just as quickly turned his attention to the supply of hamburger patties, taking a methodical approach to implementing HACCP from feedlots and slaughter to the ground beef operations that produced the hamburger patties. Few “grinding operations” at the time were willing to implement a new microbial monitoring program to test both the incoming meat and the raw ground hamburger patties for E. coli O157:H7. However, Texas American and CTI Foods both signed on to adopt the new system; and by implementing the program, the industry as a whole learned much more about how pathogenic E. coli enters the supply and production system.

Over time, additional slaughter and fabrication mitigation steps were employed to reduce microbial loads. While testing was used to exclude contaminated supply, the intention of the testing program was to learn and make continuous improvements to the controls within the process. Fundamental to the success of the testing program was defining and tracking “lots” within the process to allow for traceability and proper rotation. Microbial testing results of the beef supply became a defining metric for Jack in the Box’s leadership team.

One of the most meaningful actions Dave took was to openly share the testing program and controls with anyone in industry who was interested, including competing restaurant chains. He firmly believed that there was no competitive advantage in food safety. We have learned over time that an illness outbreak from one company can have negative impacts on an entire food industry segment—peanut butter, tomatoes, cantaloupes, and lettuce, to name a few.

Quality and Process Control through HACCP

Before joining Jack in the Box, Dave Theno had already pioneered the use of HACCP and its concepts to achieve microbial reduction through “process control.” Before Jack in the Box, Dave had built a very successful consulting business working with clients who wanted to implement process control through HACCP in their organizations. At the start of his career, he demonstrated that by identifying and monitoring key steps within the poultry slaughter process, the rate of Salmonella contamination in chilled carcasses could be reduced from 35 percent to around 1–2 percent. Even for processes where there is no “kill step,” such as slaughter, identifying the key steps within the process that can be controlled and measured, and then measuring them, helps achieve microbial reduction through data visibility and continuous process improvement. This is exactly what happened as a result of the microbial testing that was implemented for Jack in the Box’s ground beef supply. The data allowed for examination of processes further back in the supply chain and identified areas where additional microbiological control technologies would help reduce the overall level of E. coli. Consequently, over the three decades since the program was implemented, the U.S. ground beef supply has far less exposure to pathogenic E. coli, and illnesses associated with ground beef have been substantially reduced.

In the 1980s and early 1990s, not everyone at the U.S. Department of Agriculture (USDA) or in the industry was a proponent of controlling processes through the use of HACCP, even though the National Aeronautics and Space Administration (NASA) had successfully used it to ensure safe food for their astronauts in space. The traditional process of government inspectors visually inspecting and stamping every animal carcass to declare safety was entrenched and viewed by many in the meat industry and government as successful. After all, the HACCP detractors reasoned, the consumer was surely responsible enough to know to cook raw meat thoroughly before eating it. The HACCP proponents would correctly point out, however, that pathogenic microbial contamination cannot be observed through traditional visual inspection. A new system of controls during the slaughter and manufacturing processes was needed to enhance visual inspection. The Jack in the Box outbreak softened attitudes toward HACCP, creating a window of opportunity for change, and in July 1996, a final rule—Pathogen Reduction; Hazard Analysis and Critical Control Points (HACCP) Systems—was published in the Federal Register.5 It became known as USDA’s “Mega Reg.” Timothy Lytton’s 2019 book, Outbreak, provides additional insight into the history behind the development of this regulation.6

In 1996, I had just started my career in the food manufacturing industry as Quality and Process Control Engineer for Hormel Foods. At the time, Hormel used a Total Quality Control program in its manufacturing plants to ensure that its processes were in control and producing safe, consistent product. Each step of the process was clearly defined, and the program outlined how each step in the process was to be monitored, and by whom. Each page of the 60-plus-page document was approved and stamped by USDA’s Food Safety and Inspection Service (FSIS). Any changes, no matter how minor, needed to be reviewed and approved by USDA. Thus, USDA approved the program under which the plant operated, and routinely inspected the approved individual activities required by the program, essentially serving as quality control. If the program required pulling 60 cans of chili after the cooking process and incubating them, the USDA inspector would create a Process Deficiency Report (the predecessor of today’s Noncompliance Reports) if they counted only 59 in the incubator. The role of Quality and Process Control Engineers at Hormel was to ensure that the processes were continuously in control and to bring them back into control when necessary. The USDA inspector’s role was to inspect the plant and its processes and notify plant management when deficiencies in approved processes were observed.

The implementation of HACCP largely turned the development and monitoring of process control systems over to the manufacturing plants, theoretically reducing the burden on regulators. The plants developed their control programs using the principles of HACCP, and USDA’s new role was to ensure that the plant was executing its HACCP system—which was more of a quality assurance vs. quality control approach. At the time, I was tasked with writing the new plans and implementing them at the plant level. For the companies that employed Total Quality Control plans, the switch to HACCP was relatively easy since the controls in the process were already defined. For many smaller companies, however, implementing HACCP was a long and difficult journey.

The Jack in the Box outbreak propelled an entire industry into a new way of monitoring process controls within manufacturing plants and shifted USDA’s role in food manufacturing from control to oversight, a system that continues today.

Thirty Years Later

The story of E. coli O157:H7 cannot be told without discussing Dr. Dave Theno and his contributions to the safety of our nation’s food supply.

The root causes of the Jack in the Box outbreak largely shaped many of Dave’s philosophies about food safety. Manage risk as far back in the supply chain as possible, implement microbiological testing programs when the data can be meaningful in driving continuous process improvement, design solid processes, and ensure they are in control from “farm to fork.” The learnings from his early career work in process control measurement remain universal. Every process, even processes without steps to reduce or eliminate harmful bacteria, can be measured at key steps. That measurement data can be used to monitor process control and continuous process improvement.

Lastly, “you get what you demonstrate you want.” This means that, as a leader, your employees will deliver on what is important to you—not necessarily what you say, but what you demonstrate is important through your actions, what you measure, and how you publicly acknowledge and reward employee performance. Those actions are important concepts in today’s ongoing discussion about creating food safety cultures within organizations. As an operations vice president, if your first question to your plant management team is about order fill rates, production line efficiencies, or labor costs, then you have clearly established what is first and foremost on your mind. If your first question is about environmental monitoring results, critical control point compliance, or reported customer complaints, then you are demonstrating that food safety is your top priority. Plant management is able to keep track of all these metrics, of course, but the order in which you ask about them communicates your priorities as leader. Those priorities will become your team’s priorities.

At a memorial service for Dave Theno in 2016, Bill Marler, the attorney who sued Foodmaker and won substantial settlements on behalf of his clients, spoke about Dave and his legacy. For any other person, it might have been odd to have the attorney who sued the company you worked for attend your memorial service, but not so for Dave. In the years following the outbreak, he maintained open communication with Bill Marler. Not in the sense of “keep your enemies close,” but because their collective goal, even working on opposite sides of the fence, was the same: make the food supply as safe as it can be. Dave truly lived by his words that he was working for Lauren Rudolph and everyone she represented.

Dave was a well-respected thought leader in food safety, known by regulators, industry, and litigation attorneys alike. He trained a generation of food safety leaders to continue working toward a safer food supply by applying science and common sense to process control and decision-making through data analysis. His larger-than-life personality also helped elevate the role and visibility of food safety as a profession. When I began my career in food manufacturing in the 1990s, it was in the quality control department; food safety departments did not yet exist. Today, we continue to see more food manufacturers with a dedicated, experienced executive to lead an independent food safety function. The most progressive companies have this position on the top line of their organizational chart—along with sales, marketing, operations, research and development, supply chain, human resources, legal, and finance. The role is not buried beneath someone else’s responsibilities, such as operations or supply chain.

For those of us in the business of making and serving food for human consumption (and especially those of us with “food safety” in our job titles), we should all carry a picture of Lauren Rudolph as a reminder of whom we ultimately work for and represent. Had she not eaten a hamburger, Lauren would have turned 37 this year; and Riley Detwiler, who did not eat a hamburger but died anyway, would have turned 32.


1.   Marler, Bill. “What if in 1982 McDonalds had been named as the source of forty-seven sickened by E. coli O157:H7-tainted hamburger in two states?” Marler Blog. February 8, 2012.

2.   Riley, L. W., R. S. Remis, S. D. Helgerson, et al. “Hemorrhagic colitis associated with a rare Escherichia coli serotype.” New England Journal of Medicine 308, no. 12 (March 24, 1983): 681–685.

3.   Russell, Cristine. “Underdone Burgers Probed in Outbreak Of Intestinal Illness.” The Washington Post. October 9, 1982.

4.   Benedict, Jeff. Poisoned: The True Story of the Deadly E. Coli Outbreak That Changed the Way Americans Eat. Inspire Books: May 1, 2011.

5.   Office of the Federal Register. Pathogen Reduction; Hazard Analysis and Critical Control Point (HACCP) Systems. 61 FR 38806. July 25, 1996.

6.   Lytton, Timothy. Outbreak: Foodborne Illness and the Struggle for Food Safety. Chicago, Illinois: University of Chicago Press (April 16, 2019).

Andrew Kesler worked for Dr. David Theno at Jack in the Box, and later as part of Dave’s food safety consulting company, Gray Dog Partners, which he founded with his wife, Jill, after retiring from Jack in the Box as Chief Food Safety Officer. Dave’s life work was food safety, which he expertly pursued to the very end. Andrew Kesler serves as Corporate Director of Supplier Compliance for America’s leading producer of salads and fresh, healthy foods. Previously, he managed supplier food safety programs for McDonald’s, Jack in the Box, and Qdoba restaurants. He also provided supplier management support to Subway and other clients as part of Dave Theno’s Gray Dog Partners food safety consulting team. Mr. Kesler began his career in food manufacturing at Hormel Foods after serving in the U.S. Air Force.