College of Veterinary Medicine

AAHP Field Disease Investigation Unit (FDIU)

Symptoms and Risks of Foodborne Illness


People who are at risk for infection with E. coli O157, Salmonella species, or Campylobacter species include anyone eating undercooked or mishandled food products, drinking inadequately treated water, and anyone in contact with farm animals or domestic pets.

The most common food vehicles for Salmonella include eggs, poultry, meat and meat products. Salmonella also has been found in commercially prepared and packaged foods such as cake mixes, cookie dough, dinner rolls, cornbread mixes, coconut meal, salad dressings, mayonnaise, milk, and others (1).

More E. coli O157 outbreaks have been linked to beef than to any other food source (1). But beef is not the only source of outbreaks. Unpasteurized apple cider, salad bar items, drinking and recreational water, and other contaminated foods have also carried the bacterium.

Why do commercial, non-meat products have disease-causing organisms? Perhaps the product contains egg or meat products that were mishandled. In one disease outbreak, milk was transported in trucks previously used to transport egg product. The milk became contaminated, and was used to produce ice cream. Since the milk was pasteurized and should have been safe, the product was not treated to kill the bacteria, and consumers became ill (1).

When a safe product comes into contact with an unsafe residue from another product, cross contamination occurs. It can happen in any kitchen. Keeping food preparation surfaces clean and sterilizing utensils used to prepare raw foods can help keep cross contamination from occurring in the home.

References:

Jay, J.M. Modern Food Microbiology, Fifth Edition. New York: Chapman and Hall, 1996.

Escherichia coli O157:H7 Symptoms

Bacteria name: Escherichia coli O157:H7

Synonyms: EHEC, VTEC

Ingesting as few as 10 organisms can cause clinical disease in humans. Symptoms occur between 3 and 8 days after ingestion. Symptoms begin with diarrhea, then progress to bloody diarrhea with severe abdominal cramps. Sometimes patients suffer from nausea and vomiting. Fever is rare. Between 2 and 7 percent of patients progress to kidney complications called hemolytic uremic syndrome (HUS). HUS is associated with O157 strains that produce only shiga toxin 2, and consists of hemolytic anemia, thrombocytopenia, and acute renal failure (1).

Infection is easily prevented by washing hands after handling potentially contaminated items, and by proper food handling.

Skin contact: Wash skin area (e.g. hands) with soap and water after skin contact.

Ingestion: if ingested, infection may be followed by diarrhea, bloody diarrhea, abdominal cramps, nausea, vomiting, and less commonly renal (kidney) complications. See a physician immediately for these symptoms.


Salmonella enterica Symptoms

Bacteria name: Salmonella enterica

Ingestion of between one million and ten million organisms may cause disease in humans. Symptoms usually develop within 12 to 14 hours after ingestion and include diarrhea which may progress to a bloody diarrhea, accompanied by severe abdominal cramps. They include nausea, vomiting, headache, and chills. Other symptoms include prostration, muscular weakness, faintness, moderate fever, restlessness, and drowsiness. Symptoms persist for 2-3 days. Infection is easily prevented by washing hands after handling potentially contaminated items, and by proper food handling. The average mortality rate by age group is:
  • 0-1 years: 5.8 %
  • 1-50 years: 2 %
  • over 50: 15 %

Up to 5% of patients continue to excrete infectious organisms after symptoms go away. These "carriers" can pass the disease around through poor hygeine and food handling practices (1).

Skin contact: Wash skin area (e.g. hands) with soap and water after skin contact.

Ingestion: if ingested, infection may be followed by diarrhea, bloody diarrhea, abdominal cramps, nausea, and vomiting. See a physician immediately for these symptoms.

References:

Jay, J.M. Modern Food Microbiology, Fifth Edition. New York: Chapman and Hall, 1996.

Last Edited: Nov 18, 2009 11:17 AM   

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