Oysters. Bacon. Ice cream. What reads like a decadent shopping list or Mad Men-era prix fixe menu is also an incomplete list of vectors of foodborne illness from the past decade.
Listeria monocytogenes – among the most lethal bacterial food poisoning pathogens nationally – tainted Brenham-based Blue Bell ice cream in 2015 and Boar’s Head bacon and deli meats in 2025. In 2022 Galveston Bay oysters sickened dozens of consumers with gastrointestinal illness. While that batch of oysters wasn’t contaminated by Vibrio, a bacterium that usually causes enteric symptoms but in its most severe form can be fatal or require limb amputation, in 2023 a Galveston County man who was immunosuppressed died of Vibrio after eating raw oysters.
Those are some of the more recent outbreaks of foodborne illness, but food contamination isn’t new. Prior to the Food and Drug Administration’s (FDA’s) establishment in 1906, “farmers were not uncommonly adulterating their milk with dirty water, pepper contained dirt, coffee contained ground bone, and cheddar cheese was colored by red lead,” said Charles J. Lerner, MD, a retired infectious diseases physician and hospital epidemiologist in San Antonio.
Even with FDA oversight curtailing those problems, “[foodborne illnesses] haven’t gone away,” the longtime consultant to the Texas Medical Association’s Committee on Infectious Diseases said. “They are continuing to be a problem.”
The Centers for Disease Control and Prevention (CDC) estimates each year some 48 million people get sick from a foodborne illness, more than 127,000 are hospitalized, and 3,000 die (tma.tips/FoodborneEstimates). The Texas Department of State Health Services (DSHS), which catalogs the statewide incidence of foodborne illnesses caused by various pathogens, notes the documented cases reflect underreporting, which the agency attributes in part to:
- Patients not being tested when they have a diarrheal illness;
- People who have only mild symptoms not visiting their physician; and
- Lack of medical care access, especially in rural areas or among immigrant communities.
Amid underreporting, overlapping symptoms, and factors that increase patients’ risk such as age and immunocompromised status, foodborne illness presents a web of clues for physicians to untangle. TMA members and health officials offer guidance below for decoding the cause of specific cases of illness and how to help public health authorities stall or contain outbreaks.
Norovirus vigilance
Norovirus, the most common agent of foodborne illness, “can be pretty much anywhere, even in comfortable environments like cruise ships,” said Vincent Fonseca, MD, MPH. The San Antonio preventive medicine specialist offers a simple fix. “Frequent handwashing is the best defense in these situations.”
CDC affirms Dr. Fonseca’s guidance – the agency telegraphed earlier this year that hand sanitizer alone does not work well against the virus (tma.tips/NorovirusPrevention).
One place norovirus, which Dr. Lerner calls “extraordinarily contagious,” isn’t found is in DSHS’ list of notifiable conditions. That exclusion dovetails with CDC’s policy, which doesn’t require state and local health departments to report norovirus cases, and, accordingly, most hospitals and health care providers don’t test for it, DSHS says. Despite a notification apparatus not being in place for norovirus statewide or nationally, it merits physicians’ attention as the leading cause of foodborne illness in the U.S. and being implicated in hundreds of deaths annually (tma.tips/NorovirusCDC).
The list of Texas’ notifiable conditions, a printable file available on the DSHS website, includes the most common foodborne illnesses, among other diseases, and reporting timelines. The online document links to a hub for disease reporting contacts at each county’s local or regional health department. (See “Report Card,” page 35.)
‘Even a single case’
Physicians provide crucial insight to public health teams when they promptly report any notifiable illness, let alone foodborne illness, says Janeana White, DO, deputy public health authority for the Houston Health Department.
“Timely and accurate reporting and having clear communication between the physician and public health are essential for identifying and stopping foodborne outbreaks before they can increase or escalate,” said Dr. White, a member of TMA’s Committee on Infectious Diseases. “A physician’s diagnosis can help prevent more people from getting sick.”
“Even a single case of a certain pathogen, like E. coli or listeria or salmonella, can be the first sign of a larger outbreak, so prompt reporting protects both the individual patient and the broader community,” Dr. White said.
While international travel increases the risk of contracting a foodborne illness, typically due to differing food safety standards abroad, Dr. White says, she cites listeriosis as a case study of how outbreaks of reportable illnesses often take root in foods we regularly consume stateside.
“From 2011 to 2020, the average number of cases reported in Texas of listeriosis [was] about 40 per year, ranging from 19-65. But when we look at recent outbreaks in Texas, they involved certain types of cheeses, they included diced celery, whole cantaloupe, caramel apples, and ice cream products,” she said. “So these infections aren’t necessarily involving someone who traveled somewhere else; sometimes it’s the food that has been brought back when we traveled or that has been imported.”
“A physician’s clinical suspicion goes a long way in protecting individuals’ and the community’s health,” Dr. White added.
Information gathering and serious symptoms
Anything that impairs a patient’s immune system can put them at greater risk for severe illness from food poisoning, Dr. Lerner notes. This can include patients who receive chemotherapy or have an organ transplant, patients with certain autoimmune diseases, patients who live with HIV, and something as seemingly innocuous as taking antacids, which impair the gastrointestinal tract’s ability to destroy pathogens by reducing gastric acidity.
Dr. Fonseca, a consultant on TMA’s Council on Science and Public Health, outlines a shortlist of information for physicians to probe into when foodborne illness is a concern:
- Travel history;
- Close contacts with similar symptoms;
- Group settings (e.g., restaurants, workplaces, and social gatherings where people share food);
- Consumption of produce; and
- Consumption of raw or undercooked foods or foods that are handled a lot after cooking.
Nausea, vomiting, diarrhea, and abdominal cramping commonly occur in episodes of foodborne illness, Dr. Fonseca says, and he recommends physicians be especially watchful for cases where patients experience bloody diarrhea or fever, symptoms he says suggest bacterial agents of illness. He advises getting a food and drink history from affected patients of at least three days and up to seven days.
“If there are neurologic symptoms, these suggest toxins,” Dr. Fonseca told Texas Medicine. “In this case, the food and drink history should focus on the past 24 hours, and botulism or listeria meningitis are possible.”
And albeit rare, adult and infant botulism – which can be linked to home-pickled or home-canned foods – command the highest level of reporting urgency on the state’s list of notifiable conditions, alongside anthrax, measles, plague, polio, rabies, smallpox, and viral hemorrhagic fevers.
Trust as an antidote
While timely reporting by physicians can help state and local epidemiologists connect disparate strands of an outbreak – when strains of an illness from South Texas and North Texas match, for example – Dr. White says there’s another good reason for physicians to stay informed about foodborne illness symptoms and treatment protocols.
“There’s a [National Institutes of Health] study that shows around 62% of patients highly trust their physician for all health-related information, including issues around food safety,” she said (tma.tips/FoodSafetyTrust). “Because patients trust their physicians, they’re more likely to work with the physician for food safety information.”
That trust might soon become all the more critical. Federal cuts in staff and funding to agencies including CDC, FDA, and the U.S. Department of Agriculture “could have a ripple effect on state and local health departments that could potentially impact our foodborne illness teams, our ability to evaluate outbreak investigations,” Dr. White said, warning “any delay in investigating could prolong an exposure, worsening the risk of [it] becoming more widespread and the risk of worsening severity.”
Dr. Lerner cites the public health methods and strategies that stifled historical outbreaks.
“We don’t have the kinds of outbreaks of diarrhea that we used to have. If you go back in history and look at what epidemics were: typhoid epidemics [with] mortality rates up to 35%; cholera epidemics [with] mortality rates up to 60%. We don’t see that anymore, because of clean water standards and the elimination of open sewers.”
Vigilance is key to maintaining the progress that has been made, Dr. Lerner says.
“These are biologic systems, and you can’t do anything but be watchful and waiting,” he said.