9.5 Bacterial Foodborne Illness and Food Poisoning Triage
Key Takeaways
- Incubation period separates the toxin-mediated from the invasive foodborne illnesses: vomiting within 1 to 6 hours suggests preformed Staphylococcus aureus or Bacillus cereus toxin, 8 to 16 hours suggests Clostridium perfringens, and fever with diarrhea after 1 to 3 days suggests an invasive bacterium.
- Bloody diarrhea without high fever after consuming undercooked ground beef suggests Shiga toxin-producing Escherichia coli, where antibiotics and antimotility agents increase the risk of hemolytic uremic syndrome and are avoided.
- Most bacterial foodborne illness is managed with oral rehydration; referral is driven by dehydration, bloody stool, high fever, immunosuppression, pregnancy, extremes of age, and neurologic findings.
- Neurologic features change the differential entirely: descending paralysis suggests botulism, temperature reversal and paresthesias suggest ciguatera, flushing and headache minutes after fish suggests scombroid histamine, and rapid perioral numbness suggests a marine sodium channel toxin.
- Clusters of cases from a shared meal or venue require immediate public health notification, and poison centers frequently detect these outbreaks before hospital reporting systems do.
When a caller reports vomiting and diarrhea after a meal, the single most useful piece of data is time from ingestion to symptom onset. Preformed toxins act in hours; organisms that must multiply and invade take a day or more.
Toxin-Mediated Illness: Onset in Hours
| Organism | Onset | Food Vehicles | Features |
|---|---|---|---|
| Staphylococcus aureus (preformed heat-stable enterotoxin) | 1 to 6 hours | Ham, cream-filled pastries, potato and egg salad, food handled after cooking and held warm | Abrupt violent vomiting with cramps, little or no fever; resolves in 8 to 24 hours. Reheating does not destroy the toxin |
| Bacillus cereus, emetic form (cereulide) | 1 to 6 hours | Fried rice held at room temperature, pasta | Vomiting predominates; cereulide is heat stable and acid stable |
| Bacillus cereus, diarrheal form | 8 to 16 hours | Meats, sauces, vegetables | Watery diarrhea and cramps |
| Clostridium perfringens | 8 to 16 hours | Meat and poultry dishes, gravies held warm in large quantities | Cramping and watery diarrhea, minimal vomiting, no fever; resolves in 24 hours |
Invasive and Inflammatory Illness: Onset in Days
| Organism | Onset | Food Vehicles | Features and Management Notes |
|---|---|---|---|
| Salmonella (non-typhoidal) | 6 hours to 3 days (usually 12 to 36 hours) | Poultry, eggs, produce, reptile and amphibian contact | Fever, cramps, diarrhea that may be bloody; antibiotics only for severe disease, bacteremia, infants, older adults, or immunosuppression, since treatment can prolong carriage |
| Campylobacter jejuni | 2 to 5 days | Undercooked poultry, unpasteurized milk | Fever, abdominal pain that can mimic appendicitis, bloody diarrhea; later Guillain-Barré syndrome and reactive arthritis |
| Shigella | 1 to 3 days | Person-to-person, contaminated food, day care | Fever, tenesmus, dysentery; seizures in young children; antibiotics shorten illness |
| Shiga toxin-producing Escherichia coli (O157:H7 and others) | 3 to 4 days | Undercooked ground beef, unpasteurized juice and milk, sprouts, leafy greens, petting zoos | Bloody diarrhea with severe cramps and little or no fever. Avoid antibiotics and antimotility agents, which increase the risk of hemolytic uremic syndrome (hemolytic anemia, thrombocytopenia, kidney failure) in children |
| Vibrio parahaemolyticus | 4 to 96 hours | Raw or undercooked shellfish, especially oysters | Watery diarrhea, cramps |
| Vibrio vulnificus | 1 to 7 days | Raw oysters; wound exposure to seawater | Life-threatening sepsis with bullous skin lesions in patients with liver disease or iron overload; wound infections after marine injury; requires prompt antibiotics |
| Listeria monocytogenes | Days to weeks | Deli meats, soft cheeses, unpasteurized dairy, melons, refrigerated smoked seafood | Febrile gastroenteritis in healthy people; invasive disease in pregnancy (fetal loss), neonates, older adults, and immunosuppressed patients |
| Yersinia enterocolitica | 4 to 7 days | Undercooked pork, unpasteurized milk | Fever and right lower quadrant pain mimicking appendicitis; iron overload and deferoxamine therapy increase susceptibility |
| Enterotoxigenic E. coli (traveler's diarrhea) | 1 to 3 days | Contaminated food and water abroad | Watery diarrhea; oral rehydration, with antibiotics for moderate to severe illness |
| Norovirus (viral, but the leading cause) | 12 to 48 hours | Shellfish, produce, person-to-person, cruise ships and institutions | Explosive vomiting and diarrhea for 24 to 60 hours; extremely contagious; rehydration only |
| Clostridioides difficile | After antibiotic exposure | Not classically foodborne | Consider when diarrhea follows recent antibiotics |
When the Findings Are Not Gastrointestinal
Neurologic or cutaneous features move the diagnosis away from ordinary bacterial gastroenteritis.
| Clue | Likely Cause |
|---|---|
| Flushing, headache, palpitations, and urticaria within 10 to 30 minutes of eating fish | Scombroid histamine poisoning; treat with H1 and H2 blockers |
| Paresthesias, temperature reversal, and "loose teeth" after reef fish | Ciguatera |
| Rapid perioral numbness, then ascending paralysis with a clear mind after pufferfish or shellfish | Tetrodotoxin or saxitoxin |
| Blurred vision, dysarthria, dysphagia, and symmetric descending paralysis without fever | Botulism |
| Vomiting and confusion after wild mushrooms, with a delay of 6 to 24 hours | Amatoxin |
| Sweating, salivation, bradycardia after a meal of foraged mushrooms | Muscarinic mushrooms |
| Cholinergic symptoms in a farm worker after a meal | Consider pesticide contamination of the food |
| Hypocalcemia, kidney injury after a large amount of star fruit or rhubarb leaves | Soluble oxalate |
Management and Referral
Home Management
Most adults and older children with a short toxin-mediated illness and no red flags do well with oral rehydration solution taken in small frequent volumes, gradual reintroduction of bland foods, and scheduled follow-up calls. Loperamide may be considered in an adult with watery, non-bloody, non-febrile diarrhea, but it is avoided in children and in anyone with fever or bloody stool.
Referral Criteria
- Signs of dehydration: no urine output for 8 to 12 hours, no tears, sunken fontanelle, lethargy, orthostasis
- Bloody diarrhea, severe abdominal pain, or a temperature above 38.9 °C (102 °F)
- Vomiting that prevents oral rehydration
- Infants younger than 6 months, frail older adults, pregnancy (listeriosis risk), immunosuppression, chronic liver disease (Vibrio risk), or inflammatory bowel disease
- Any neurologic finding, or suspicion of botulism, marine neurotoxin, or mushroom poisoning
- Recent antibiotic use with severe diarrhea
Laboratory and Public Health
- Stool culture, Shiga toxin testing, and molecular panels are used for bloody or febrile diarrhea and for outbreak investigation.
- In a suspected Shiga toxin case, follow the complete blood count, smear for schistocytes, platelet count, and creatinine for at least a week, because hemolytic uremic syndrome typically appears 5 to 10 days after diarrhea begins.
- Report clusters. Two or more cases from a shared meal, restaurant, or event trigger notification of the local health department. Poison centers often identify these clusters first, and the National Poison Data System is used for national anomaly detection.
Poison Center Case: The Church Picnic
Six people call within an hour of each other. All ate a rice and chicken casserole at a picnic; the dish sat on a warming tray for several hours. Everyone became ill with abrupt vomiting 2 hours after eating, with cramps and minimal diarrhea and no fever. One caller is a 78-year-old man with three episodes of vomiting who feels weak and dizzy.
Specialist reasoning. The very short incubation with vomiting predominating points to a preformed toxin, most likely Staphylococcus aureus or the emetic toxin of Bacillus cereus from temperature-abused rice. The illness is self-limited, so healthy adults receive instructions for small-volume oral rehydration and a follow-up call. The 78-year-old with orthostatic symptoms is referred for evaluation and intravenous fluids. Because this is a cluster from a shared meal, the CSPI documents the food histories, notifies the local health department, and advises that the remaining food be refrigerated and retained for testing rather than discarded.
Four family members develop abrupt vomiting and cramps 2 hours after eating fried rice from a buffet that sat at room temperature. No one has a fever. Which agent and management plan is most consistent?
A 5-year-old has three days of worsening bloody diarrhea and severe cramps, with a temperature of 37.6 °C, after eating undercooked hamburger. Which management advice is correct?
A pregnant woman at 22 weeks calls after learning that deli meat she ate for several weeks was recalled. She feels well. Which organism drives the concern and what is the appropriate response?