Both consumers and food industry interests benefit from being fully informed about the true nature of foodborne illnesses. The complex realities of foodborne illnesses demand that formal medical insight and study is needed to determine the type of outbreak being dealt with at any given time and place. Still, it can be of benefit for any stakeholder in the food industry to learn more about these differing illnesses and their effects on consumers.
For example, just within the realm of bacterial outbreaks, incubation times can range from a few hours to a few months and symptoms can range from fevers and headaches to severe abdominal pain and paralysis, depending on the type of bacteria. The following graph from the CDC* describes incubation periods, symptoms, and other information about foodborne illnesses for a general audience.
Table B-1. Guidelines for Confirmation of Foodborne-Disease Outbreaks (Bacterial)
| Etiologic agent | Incubation period | Clinical syndrome | Confirmation |
|---|---|---|---|
| Bacillus cereus—Vomiting toxin | 1-6 hrs | Vomiting; some patients with diarrhea; fever uncommon | Isolation of organism from stool of two or more ill persons and not from stool of control patients OR Isolation of 105 organisms/g from epidemiologically implicated food, provided specimen is properly handled |
| Bacillus cereus—Diarrheal toxin | 6-24 hrs | Diarrhea, abdominal cramps, and vomiting in some patients; fever uncommon | Isolation of organism from stool of two or more ill persons and not from stool of control patients OR Isolation of 105 organisms/g from epidemiologically implicated food, provided specimen is properly handled |
| Brucella | Several days to several months; usually >30 days | Weakness, fever, headache, sweats, chills, arthralgia, weight loss, splenomegaly | Two or more ill persons and isolation of organism in culture of blood or bone marrow; greater than fourfold increase in standard agglutination titer (SAT) over several wks, or single SAT 1:160 in person who has compatible clinical symptoms and history of exposure |
| Campylobacter jejuni/coli | 2-10 days; usually 2-5 days | Diarrhea (often bloody), abdominal pain, fever | Isolation of organism from clinical specimens from two or more ill persons OR Isolation of organism from epidemiologically implicated food |
| Clostridium botulinum | 2 hrs-8 days; usually 12-48 hrs | Illness of variable severity; common symptoms are diplopia, blurred vision, and bulbar weakness; paralysis, which is usually descending and bilateral, might progress rapidly | Detection of botulinum toxin in serum, stool, gastric contents, or implicated food OR Isolation of organism from stool or intestine |
| Clostridium perfringens | 6-24 hrs | Diarrhea, abdominal cramps; vomiting and fever uncommon | Isolation of 106 organisms/g from stool of two or more ill persons, provided specimen is properly handled. OR Demonstration of enterotoxin in the stool of two or more ill persons OR Isolation of 105 organisms/g from epidemiologically implicated food, provided specimen is properly handled |
| Escherichia coli—Enterohemorrhagic (E. coli O157:H7 and others) | 1-10 days; usually 3-4 days | Diarrhea (often bloody), abdominal cramps (often severe), little or no fever | Isolation of E. coli O157:H7 or other Shiga-like toxin-producing E. coli from clinical specimen from two or more ill persons OR Isolation of E. coli O157:H7 or other Shiga-like toxin-producing E. coli from epidemiologically implicated food |
| Escherichia coli—Enterotoxigenic (ETEC) | 6-48 hrs | Diarrhea, abdominal cramps, nausea; vomiting and fever less common | Isolation of organism of same serotype, demonstrated to produce heat-stable (ST) and/or heat-labile (LT) enterotoxin, from stool of two or more ill persons |
| Escherichia coli—Enteropathogenic (EPEC) | Variable | Diarrhea, fever, abdominal cramps | Isolation of organism of same enteropathogenic serotype from stool of two or more ill persons |
| Escherichia coli—Enteroinvasive (EIEC) | Variable | Diarrhea (might be bloody), fever, abdominal cramps | Isolation of same enteroinvasive serotype from stool of two or more ill persons |
| Listeria monocytogenes—Invasive disease | 2-6 weeks | Meningitis, neonatal sepsis, fever | Isolation of organism from normally sterile site |
| Listeria monocytogenes—Diarrheal disease | Unknown | Diarrhea, abdominal cramps, fever | Isolation of organism of same serotype from stool of two or more ill persons exposed to food that is epidemiologically implicated or from which organism of same serotype has been isolated |
| Nontyphoidal Salmonella | 6 hrs-10 days; usually 6-48 hrs | Diarrhea, often with fever and abdominal cramps | Isolation of organism of same serotype from clinical specimens from two or more ill persons OR Isolation of organism from epidemiologically implicated food |
| Salmonella Typhi | 3-60 days; usually 7-14 days | Fever, anorexia, malaise, headache, and myalgia; sometimes diarrhea or constipation | Isolation of organism from clinical specimens from two or more ill persons OR Isolation of organism from epidemiologically implicated food |
| Shigella spp. | 12 hrs-6 days; usually 2-4 days | Diarrhea (often bloody), often accompanied by fever and abdominal cramps | Isolation of organism of same serotype from clinical specimens from two or more ill persons OR Isolation of organism from epidemiologically implicated food |
| Staphylococcus aureus | 30 min-8 hrs; usually 2-4 hrs | Vomiting, diarrhea | Isolation of organism of same phage type from stool or vomitus of two or more ill persons OR Detection of enterotoxin in epidemiologically implicated food OR Isolation of 105 organisms/g from epidemiologically implicated food, provided specimen is properly handled |
| Streptococcus, group A | 1-4 days | Fever, pharyngitis, scarlet fever, upper respiratory infection | Isolation of organism of same M- or T-type from throats of two or more ill persons OR Isolation of organism of same M- or T-type from epidemiologically implicated food |
| Vibrio cholerae—O1 or O139 | 1-5 days | Watery diarrhea, often accompanied by vomiting | Isolation of toxigenic organism from stool or vomitus of two or more ill persons OR Significant rise in vibriocidal, bacterial-agglutinating, or antitoxin antibodies in acute- and early convalescent-phase sera among persons not recently immunized OR Isolation of toxigenic organism from epidemiologically implicated food |
| Vibrio cholerae—non-O1 and non-O139 | 1-5 days | Watery diarrhea | Isolation of organism of same serotype from stool of two or more ill persons |
| Vibrio parahaemolyticus | 4-30 hrs | Diarrhea | Isolation of Kanagawa-positive organism from stool of two or more ill persons OR Isolation of 105 Kanagawa-positive organisms/g from epidemiologically implicated food, provided specimen is properly handled |
| Yersinia enterocolitica | 1-10 days; usually 4-6 days | Diarrhea, abdominal pain (often severe) | Isolation of organism from clinical specimen from two or more ill persons OR Isolation of pathogenic strain of organism from epidemiologically implicated food |
Table B-2. Guidelines for Confirmation of Foodborne-Disease Outbreaks (Chemical)
| Etiologic Agent | Incubation Period | Clinical Syndrome | Confirmation |
|---|---|---|---|
| Marine toxins—Ciguatoxin | 1-48 hrs; usually 2-8 hrs | Usually gastrointestinal symptoms followed by neurologic symptoms (including paresthesia of lips, tongue, throat, or extremities) and reversal of hot and cold sensation | Demonstration of ciguatoxin in epidemiologically implicated fish OR Clinical syndrome among persons who have eaten a type of fish previously associated with ciguatera fish poisoning (e.g., snapper, grouper, or barracuda) |
| Marine toxins—Scombroid toxin (histamine) | 1 min-3 hrs; usually <1 hr | Flushing, dizziness, burning of mouth and throat, headache, gastrointestinal symptoms, urticaria, and generalized pruritis | Demonstration of histamine in epidemiologically implicated fish OR Clinical syndrome among persons who have eaten a type of fish previously associated with histamine fish poisoning (e.g., mahi-mahi or fish of order Scomboidei) |
| Marine toxins—Paralytic or neurotoxic shellfish poison | 30 min-3 hrs | Paresthesia of lips, mouth or face, and extremities; intestinal symptoms or weakness, including respiratory difficulty | Detection of toxin in epidemiologically implicated food OR Detection of large numbers of shellfish-poisoning-associated species of dinoflagellates in water from which epidemiologically implicated mollusks are gathered |
| Marine toxins—Puffer fish, tetrodotoxin | 10 min-3 hrs; usually 10-45 min | Paresthesia of lips, tongue, face, or extremities, often following numbness; loss of proprioception or floating sensations | Demonstration of tetrodotoxin in epidemiologically implicated fish OR Clinical syndrome among persons who have eaten puffer fish |
| Heavy metals (Antimony, Cadmium, Copper, Iron, Tin, Zinc) | 5 min-8 hrs; usually <1 hr | Vomiting, often metallic taste | Demonstration of high concentration of metal in epidemiologically implicated food |
| Monosodium glutamate (MSG) | 3 min-2 hrs; usually <1 hr | Burning sensation in chest, neck, abdomen, or extremities; sensation of lightness and pressure over face or heavy feeling in chest | Clinical syndrome among persons who have eaten food containing MSG (e.g., usually 1.5 g MSG) |
| Mushroom toxins—Shorter-acting toxins (Muscimol, Muscarine, Psilocybin, Coprinus artrementaris, Ibotenic acid) | 2 hrs | Usually vomiting and diarrhea, other symptoms differ with toxin
| Clinical syndrome among persons who have eaten mushroom identified as toxic type OR Demonstration of toxin in epidemiologically implicated mushroom or food containing mushroom |
| Mushroom toxins—Longer-acting toxins (e.g., Amanita spp.) | 6-24 hrs | Diarrhea and abdominal cramps for 24-hrs followed by hepatic and renal failure | Clinical syndrome among persons who have eaten mushroom identified as toxic type OR Demonstration of toxin in epidemiologically implicated mushroom or food containing mushrooms |
Table B-3. Guidelines for Confirmation of Foodborne-Disease Outbreaks (Parasitic)
| Etiologic Agent | Incubation Period | Clinical Syndrome | Confirmation |
|---|---|---|---|
| Cryptosporidium spp. | 2-28 days; median 7 days | Diarrhea, nausea, vomiting, fever | Demonstration of oocysts in stool or in small-bowel biopsy of two or more ill persons OR Demonstration of organism in epidemiologically implicated food |
| Cyclospora cayetanensis | 1-14 days; median: 7 days | Diarrhea, nausea, anorexia, weight loss, cramps, gas, fatigue, low-grade fever; may be relapsing or protracted | Demonstration of the parasite by microscopy or molecular methods in stool or in intestinal aspirate or biopsy specimens from two or more ill persons OR Demonstration of the parasite in epidemiologically implicated food |
| Giardia intestinalis | 3-25 days; median: 7 days | Diarrhea, gas, cramps, nausea, fatigue | Demonstration of the parasite in stool or small-bowel biopsy specimen of two or more ill persons |
| Trichinella spp. | 1-2 days for intestinal phase; 2-4 weeks for systemic phase | Fever, myalgia, periorbital edema, high eosinophil count | Two or more ill persons and positive serologic test or demonstration of larvae in muscle biopsy OR Demonstration of larvae in epidemiologically implicated meat |
Table B-4. Guidelines for Confirmation of Foodborne-Disease Outbreaks (Viral)
| Etiologic Agent | Incubation Period | Clinical Syndrome | Confirmation |
|---|---|---|---|
| Hepatitis A | 15-50 days; median: 28 days | Jaundice, dark urine, fatigue, anorexia, nausea | Detection of immunoglobulin M antibody to hepatitis A virus (IgM anti-HAV) in serum from two or more persons who consumed epidemiologically implicated food |
| Norovirus (NoV) | 12-48 hrs (median 33 hours) | Diarrhea, vomiting, nausea, abdominal cramps, low-grade fever | Detection of viral RNA in at least two bulk stool or vomitus specimens by real-time or conventional reverse transcriptase-polymerase chain reaction (RT-PCR) OR Visualization of viruses (NoV) with characteristic morphology by electron microscopy in at least two or more bulk stool or vomitus specimens OR Two or more stools positive by commercial enzyme immunoassay (EIA) |
| Astrovirus | 12-48 hrs | Diarrhea, vomiting, nausea, abdominal cramps, low-grade fever | Detection of viral RNA in at least two bulk stool or vomitus specimens by real-time or conventional reverse transcriptase-polymerase chain reaction (RT-PCR) OR Visualization of viruses (NoV) with characteristic morphology by electron microscopy in at least two or more bulk stool or vomitus specimens OR Two or more stools positive by commercial enzyme immunoassay (EIA) |
*Source: Centers for Disease Control and Prevention. 2017. https://www.cdc.gov/foodsafety/outbreaks/investigating-outbreaks/confirming_diagnosis.html
