AF Form 431: Food Poisoning Outbreak Case History Guide

AF Form 431: Food Poisoning Outbreak Case History Guide – Foodborne illness outbreaks pose a serious risk in military settings, where large groups share dining facilities, field rations, or catered events. The U.S. Air Force uses AF Form 431, officially titled Food Poisoning Outbreak – Individual Case History, as a key tool in outbreak investigations. Public Health (PH) teams rely on this form to document what affected individuals ate in the 72 hours before symptoms began, helping identify the contaminated food source quickly and prevent further cases.

This article explains the purpose of AF Form 431, how it fits into Air Force food safety protocols, when and how to use it, and why accurate completion matters for force readiness and public health.

What Is AF Form 431?

AF Form 431 is a standardized Department of the Air Force form designed specifically for recording an individual’s food consumption history during a suspected food poisoning (foodborne illness) outbreak. It captures detailed dietary information from affected personnel to support epidemiological analysis.

  • Full Title: Food Poisoning Outbreak – Individual Case History
  • Primary Use: Document foods and beverages consumed in the 72 hours prior to symptom onset.
  • Companion Form: Often paired with AF Form 432 (Time Distribution of Persons Affected), which helps plot the epidemic curve by tracking when symptoms started.
  • Official Download: Available as a PDF from the Air Force e-Publishing site: https://static.e-publishing.af.mil/production/1/af_sg/form/af431/af431.pdf

The form supports rapid investigation by Public Health teams at military treatment facilities (MTFs) and aligns with broader Department of the Air Force Instruction (DAFI 48-116, Food and Water Protection Program, dated 10 March 2023).

Why Does the Air Force Use AF Form 431?

Military environments—dining facilities, deployed operations, mess halls, or events—can facilitate rapid spread of pathogens like Salmonella, Campylobacter, E. coli, Staphylococcus aureus, or norovirus if contamination occurs. Quick identification of the source protects mission readiness by minimizing downtime from illness.

According to DAFI 48-116, Public Health uses AF Form 431 as part of the required toolkit for foodborne illness (FBI) investigations. It helps:

  • Map common food exposures across cases.
  • Calculate attack rates for specific menu items.
  • Support laboratory testing decisions for suspect foods.
  • Contribute to the overall outbreak report, including the CDC Form 52.13 (Investigation of a Foodborne Outbreak).

All foodborne illness outbreaks must be reported to Medical Group (MDG) leadership, the Major Command (MAJCOM) PH Officer, and the appropriate state health department (for CONUS, Alaska, or Hawaii locations). Air National Guard units also notify their State Joint Forces Headquarters. Direct reporting to the CDC is not authorized—go through proper channels.

Suspected intentional contamination triggers additional coordination with Security Forces and the Anti-Terrorism Officer.

When Is AF Form 431 Required?

Public Health initiates use of AF Form 431 when:

  • Two or more people experience similar gastrointestinal symptoms (nausea, vomiting, diarrhea, abdominal cramps, fever) after sharing a common meal or food source.
  • A single case of a high-priority pathogen meets reportable medical event criteria under AFMAN 48-105 and Armed Forces Reportable Medical Events Guidelines.
  • Routine food facility inspections, complaints, or ALFOODACT (DoD hazardous food recall) alerts suggest a potential outbreak.

The form focuses on the 72-hour food history because most bacterial and viral foodborne pathogens have incubation periods within this window.

How to Complete AF Form 431?

While the exact layout is in the official PDF, the form typically collects:

  • Case Identification: Name, rank/grade, SSN or DoD ID, unit, age, sex, and contact information.
  • Symptom Details: Onset date and time, specific symptoms, duration, severity, and medical treatment received.
  • Food History: Detailed list of all foods, beverages, and meals consumed in the 72 hours before illness. This includes location (dining facility, flight kitchen, off-base restaurant, MREs, etc.), time of consumption, and any leftovers or special items.
  • Additional Exposure Information: Attendance at events, shared water sources, or other potential risk factors.
  • Interviewer/Investigator Notes: Signature, date, and PH or medical staff details.

Best Practices for Accuracy:

  • Interview the individual as soon as possible while memory is fresh.
  • Use menu records, receipts, or witness statements to verify details.
  • Record both foods eaten and foods not eaten (negative history helps rule out sources).
  • Maintain privacy per the Privacy Act statement on the form.

Completed forms feed into the larger investigation, including entry into the Air Force Disease Reporting System internet (AFDRSi) for reportable cases and outbreaks.

Integration with Broader Outbreak Response

AF Form 431 is one piece of a multi-layered response:

  1. Case Finding and Interviews — Use AF 431 for individuals.
  2. Epidemiologic Analysis — Combine with AF 432 and line lists.
  3. Environmental Assessment — Inspect food facilities using DD Form 2973 (Food Operation Inspection Report).
  4. Laboratory Support — Submit clinical specimens and suspect food samples through the MTF lab to approved DoD or state labs.
  5. Reporting — Submit CDC 52.13 to MAJCOM PH and state health department; enter data in AFDRSi.
  6. Consultation — Request assistance from USAFSAM Epidemiology Consult Service (DCPH-Dayton) if needed.

Public Health also conducts annual exercises and training using tools from the Defense Health Agency Knowledge Exchange (DHA Kx) Food Protection section.

Prevention: The Best Defense Against Food Poisoning

While AF Form 431 aids investigation after an outbreak starts, the Air Force emphasizes prevention through:

  • Strict adherence to the Tri-Service Food Code.
  • Approved food sources only (via USAPHC Circular 40-1 or equivalent).
  • Routine inspections (DD Form 2972/2973).
  • Food handler training and illness reporting.
  • Temperature controls, proper sanitation, and pest management.
  • Rapid response to ALFOODACT recalls via the Defense Logistics Agency.

Commanders, facility managers, and individuals all play roles in maintaining food safety to protect the force.

Download and Access AF Form 431

For questions about completion or outbreak response, contact your local Public Health office at the Military Treatment Facility.

Stay Mission Ready: Prompt reporting and accurate documentation with tools like AF Form 431 help the Air Force contain outbreaks quickly, safeguard Airmen and families, and maintain operational effectiveness. Food safety is everyone’s responsibility.

This information is based on current DAFI 48-116 (10 March 2023) and related Air Force public health guidance. Always consult your installation Public Health team or the official form instructions for the most current procedures, as policies can be updated.

Keywords: AF Form 431, Air Force food poisoning outbreak form, foodborne illness investigation Air Force, DAFI 48-116, military public health outbreak reporting, AF Form 432, CDC 52.13 military, USAF food safety.