Linking supermarket sales data to nutritional information: an informatics feasibility study

Grocery sales are a data source of potential value to dietary assessment programs in public health informatics. However, the lack of a computable method for mapping between nutrient and food item information represents a major obstacle. We studied the feasibility of linking point-of-sale data to USDA-SR nutrient database information in a sustainable way. We analyzed 2,009,533 de-identified sales items purchased by 32,785 customers over a two-week period. We developed a method using the item category hierarchy in the supermarket's database to link purchased items to records from the USDA-SR. We describe our methodology and its rationale and limitations. Approximately 70% of all items were mapped and linked to the SR; approximately 90% of all items could be mapped with an equivalent expenditure of additional effort. 100% of all items were mapped to USDA standard food groups. We conclude that mapping grocery sales data to nutritional information is feasible.