Good companies take traceability very seriously! Source: me - a person in charge of maintaining traceability of ingredients for a food manufacturing facility
A quick word on Taco Bell: That's where we found the suspected lettuce, and it's not bc Taco Bell is gross. It's bc Taco Bell is REALLY GOOD at tracing product! Keeping track of exactly where they got their ingredients, & exactly what restaurants each shipment of ingredients went to!