NEET PG High-Yield: Investigation of Food Poisoning
Food poisoning investigation is a specialized form of epidemic investigation. Speed is essential to prevent further consumption of the contaminated source.
Key Steps in Investigation
- Collect Data: Obtain detailed food history (last 48–72 hours).
- Define Cases: Establish case definition based on clinical presentation.
- Epidemic Curve: Create a curve to determine the “incubation period” (Crucial for identifying the pathogen).
- Attack Rate: Calculate Attack Rate for each item consumed (Attacked/Total consumed).
- Identify Source: The food item with the highest attack rate is the suspected vehicle.
- Laboratory Analysis: Sample food, water, and stool/vomitus for bacterial/toxin identification.
Incubation Period Clues
| Incubation | Likely Pathogen |
|---|---|
| 1–6 hours | Staphylococcus aureus, Bacillus cereus (emetic). |
| 8–16 hours | Clostridium perfringens. |
| >16 hours | Salmonella, Shigella, E. coli. |
High-Yield NEET PG Pearls:
- Attack Rate Formula:
- Commonest Cause: *Staphylococcus aureus* is the most common cause of bacterial food poisoning due to enterotoxin.
- Emergency Action: Suspend food service from the suspected outlet immediately upon suspicion, before final laboratory confirmation.
- “Botulism” Warning: Rapid onset of neurological symptoms (diplopia, dysphagia) following ingestion of canned foods.
