Detection and prevention of food poisoning

DEFINITION: Illness, sometimes fatal, caused by eating or drinking contaminated food or water.

SIGNIFICANCE: Food poisoning incidents, both intentional and unintentional, are harmful to societies economically, psychologically, and politically. Microbial forensic analysis plays an important role in the detection and prevention of food poisoning.

Food-borne illnesses affect an estimated seventy-six million Americans every year. Although most victims recover quickly, some five thousand deaths from food poisoning occur in the United States annually. Approximately 75 percent of all food poisoning cases are caused by known pathogens; only a small percentage of food poisoning cases are caused by unknown sources or substances. Viruses, bacteria, parasites, toxins, metals, and prions that are consumed through contaminated foods and liquids, including water, cause food poisoning.

More than 250 different food-borne diseases have been identified, and the Centers for Disease Control and Prevention (CDC) estimates that 97 percent of food poisoning illnesses result from improper food handling; of these, 79 percent are caused by foods prepared in commercial kitchens and 21 percent are caused by foods prepared in home kitchens. Prepared foods left at unsafe temperatures, inadequate cooking or reheating, cross-contamination of foods, and infections in food handlers cause most food poisoning cases.

When contaminated food or water is consumed, the digestive system is usually able to destroy any harmful pathogens, but some pathogens can survive and cause illness. Usual symptoms include nausea, abdominal pain, vomiting, diarrhea, and headache; these occur normally within one to three days of ingestion of the contaminated food. Sometimes, however, a food-borne pathogen begins to multiply in the victim’s stomach and intestine, producing toxins. These toxins then travel into the bloodstream, where they are transported to vital body organs and muscles, often with lethal results. Rare pathogens such as Clostridium botulinum (the bacterium that causes botulism), which grows in improperly canned foods, and harmful substances such as arsenic or pesticides cause severe symptoms that usually result in death.

Detection

When a serious case of food poisoning is diagnosed by a physician—after other illnesses that mimic food poisoning have been ruled out—it is confirmed by laboratory analysis of fecal and blood samples and oral history from the victim. The local health department and public health scientists are usually the first responders to a suspected case of food poisoning. Preservation of is critical, and scientists carefully collect suspected food materials and samples of hair and stomach contents from the victim. Microbial forensic analysts must identify, collect, and preserve samples properly for transportation to the lab to avoid contamination of the samples.

A cluster of cases may be detected if several people connected by a common experience or event are suspected of having food poisoning. Scientists must determine whether the cases constitute more than the usual expected number of cases of a given food-borne illness or whether the reports constitute a false cluster (for example, backlogged cases reported all at one time).

Key components of a food poisoning investigation include the selection of investigatory method, analysis of samples, interpretation and validation of results, and quality assurance. If a food poisoning outbreak is identified in a particular area or in relation to a particular food, food distributors and vendors are notified immediately, and public recall notices are issued to prevent an epidemic.

Epidemiologists, forensic toxicologists and pathologists, microbiologists, and food safety and public health officials may all be called in to determine the source of a food-related contamination. Prior to 1996, many food poisoning cases went unreported to health authorities. The CDC established the Foodborne Diseases Active Surveillance Network (FoodNet) in 1996 to monitor food-borne illnesses. PulseNet, a branch of FoodNet, networks public health and food regulatory laboratories nationally and helps identify cases that are spread out over large geographic locations. PulseNet allows rapid analysis of suspected pathogens and identifies them through (deoxyribonucleic acid) fingerprinting, enabling quick detection of specific contamination sources. By combining local and regional surveillance reports, PulseNet quickly identifies suspected cases and reduces epidemic outbreaks.

Bibliography

Balkin, Karen F., ed. Food-Borne Illnesses. San Diego, Calif.: Greenhaven Press, 2004.

National Center for Food Protection and Defense. Food Defense Education: Post 9/11. Minneapolis: Author, 2007.

Scott, Elizabeth, and Paul Sockett. How to Prevent Food Poisoning: A Practical Guide to Safe Cooking, Eating, and Food Handling. Hoboken, N.J.: John Wiley & Sons, 1998.

Trestrail, John Harris, III. Criminal Poisoning: Investigational Guide for Law Enforcement, Toxicologists, Forensic Scientists, and Attorneys. 2d ed. Totowa, N.J.: Humana Press, 2007.

White, Alice E. et al. "Improving Foodborne Disease Surveillance and Outbreak Detection and Response Using Peer Networks—The Integrated Food Safety Centers of Excellence." Journal of Health Management & Practice, vol. 29, no. 3. May/June 2023, pp. 287-296, DOI: 10.1097/PHH.0000000000001607. Accessed 15 Aug. 2024.