Ingredient-specific Analyses
An ingredient-specific analysis (ISA) is an extension of a menu-level case-control study. In an ISA, exposures are evaluated at the ingredient level (e.g., “romaine”) rather than the menu item level (e.g., “Caesar salad”) during a foodborne outbreak investigation.
An ISA can be instrumental when investigating restaurant subclusters within multistate outbreaks, as it can implicate a particular ingredient.
Steps for an ingredient-specific analysis
STEP ONE
Interview cases and controls with restaurant menu
STEP TWO
Gather ingredient information (i.e., build an ingredient matrix to map your menu exposures to ingredient exposures)
- Fill in a matrix
- Use this example file OR
- Get a starter matrix by entering a few items in CodeBuilder App and then download it.
- Gather ingredient data from restaurant employees, a corporate entity, etc.
- Review the ISA Guidance Document for an overview of ISA and to assist with gathering the information at the facility.
STEP THREE
Convert your menu-level exposures to ingredient-level exposures
- The MDH Ingredient Matrix CodeBuilder App can be used to generate R/SAS/Python code.
- Download the CodeBuilder Instruction Protocol
STEP FOUR
Read in outbreak exposure data and run outbreak analysis, including the ingredient-level code.
Stuck? Get help!
If you need assistance conducting an ISA or using the CodeBuilder app, feel free to contact us!
