USDA data on daily shipments of romaine lettuce can be used to determine which production regions are free from contamination during a foodborne illness outbreak. These data, reported by USDA’s Agricultural Marketing Service with a 1- or 2-day lag, provide essentially real-time information on produce shipped out to retailers. An analysis conducted by the USDA’s Economic Research Service demonstrates how this information may allow the U.S. Food and Drug Administration (FDA) to rule out an entire production region as the source of contamination. …