Appendix B: Intentional Contamination

Table of Contents

Intentional Contamination

Intentional contamination of food can be defined as the deliberate introduction of microorganisms, chemicals, toxins or physical contaminants into a food to cause morbidity and/or mortality.  While morbidity and/or mortality may be primary goals of intentional contamination it also serves to incite fear, cause disruption, produce economic destabilization and result in severe psychological affects.  The possibility of intentional contamination must be considered in a farm-to-table approach since vulnerabilities lie throughout this continuum. Thus ensuring the safety of food is a responsibility of individuals from the farm to the table.

Food safety encompasses a variety of actions taken by numerous entities in a somewhat complex web.  Food safety involves actions taken by producers, food processors, retail food establishments, regulatory authorities and consumers.  Food security is a term that has been used for some time to mean physical and economic access to food needed for an active and healthy life.  Use of the term for the purposes of this document focuses on measures implemented to prevent the deliberate introduction of an agent into a food.   

Food safety/security practices rely on the implementation and/or enforcement of prevention and control measures.  There are materials available from a variety of sources including USDA, FDA, IDALS, etc. that focus on prevention and control measures to reduce or eliminate intentional contamination in a variety of farm-to-table settings.  This appendix will focus on the identification of possible instances of intentional contamination and necessary response actions required to ensure proper coordination of the entities involved in investigation.

  • Identifying the possibility of intentional food contamination
  • Unusual relationships between the individual, time, and location of the outbreak.
  • The presence of unusual microorganisms in host foods.
  • A shorter than usual incubation period as a result of an unusually high inoculum or more effective exposure route.
  • The presence of a large epidemic, with greater case loads than expected, especially in a discrete population.
  • More severe disease than expected for a given pathogen, as well as unusual routes of exposure.
  • A disease that is unusual for a given geographic area, is found outside the normal transmission season, or is impossible to transmit naturally in the absence of the normal vector for transmission.
  • Multiple simultaneous epidemics of different diseases.
  • Unusual strains or variants of organisms or antimicrobial resistance patterns disparate from those circulating.
  • Claims by a perpetrator of intentional contamination.
  • Knowledge that a perpetrator has access to a particular agent or agents.
  • Direct evidence of intentional contamination, with findings of equipment, supplies, or tampering.

It is important to recognize that a number of the above indicators may not be the result of an intentional contamination.  Many of the indicators described above may also be present in a naturally occurring outbreak.  Even when multiple indicators are present, it may be difficult to conclude that foodborne illness episodes or an outbreak are the result of a deliberate contamination.

Response Actions

As in any outbreak situation prevention and control measures should be implemented to reduce further morbidity and/or mortality.  When an intentional contamination is suspected contact the IDPH Center for Acute Disease Epidemiology (CADE) and the Department of Inspections and Appeals (DIA) Food and Consumer Safety Bureau immediately.  CADE and DIA can review information regarding the outbreak, and may be able to provide assistance in determining whether the contamination was intentional.  This review will aid entities involved in the investigation in communicating their findings to law enforcement personnel and may provide insight into where the criminal investigation may need to begin.  Once the law enforcement personnel have been contacted a criminal investigation can then be launched and coordinated with the foodborne outbreak investigation.  The foodborne outbreak investigation should then institute a forensic epidemiology approach to promote sharing of information amongst law enforcement, communicable disease follow-up staff, environmental health specialists, laboratorians, and state agencies.  Notification of appropriate partners allows collaboration and proper management of the investigation and issues such as, crime scene management, documentation of chain-of-custody, and handling of procedures for environmental and human specimens, as these should be considered as evidence to support a criminal investigation.  The State of Iowa Biological/Chemical Threat Agent Protocol Model contains documents and supporting materials to allow proper management of specimens.

There are a limited number of outbreaks that have been attributed to intentional food contamination.  Citations for written reports of these incidents are provided below for reference and review purposes.

  • Centers for Disease Control and Prevention. Nicotine poisoning after ingestion of contaminated ground beef—Michigan, 2003. MMWR Morb Mortal Wkly Rep. 2003;52:413–6.
  • Kolovec SA, Kimura A, Simons SL, Slutsker L, Barth S, Haley CE. An outbreak of Shigella dysenteriae type 2 among laboratory workers due to intentional food contamination. JAMA. 1997;278:396–8.
  • Torok TJ, Tauxe RV, Wise RP, Livengood JR, Sokolow R, Mauvais S, et al. A large community outbreak of salmonellosis caused by intentional contamination of restaurant salad bars. JAMA. 1997;278: 389–95.
  • Phills JA, Harrold AJ, Whiteman GV, Perelmutter L. Pulmonary infiltrates, asthma, and eosinophilia due to Ascaris suum infestation in man. N Engl J Med. 1972;286:965–70.
  • Deliberate spreading of typhoid fever in Japan. Science J. 1966;2:11–2.In addition to the citations provided above, the websites listed below provide additional information regarding food safety and food security.
  • http://www.cfsan.fda.gov/~dms/sectrain.html
  • http://www.fda.gov/oc/bioterrorism/report_congress.html
  • http://www.epa.gov/fedrgstr/EPA-IMPACT/2004/June/Day-04/i12366.htm
  • http://www.cdc.gov/nceh/ehs/ETP/food.htm
  • http://www.foodsafetyforum.org/global2/documents_en.asp http://www.findarticles.com/p/articles/mi_qa3912/is_200212/ai_n9156190
  • http://www.cdc.gov/ncidod/EID/vol11no03/04-0700.htm