With loads of ingredients coming in, being stored, transported, processed and packaged, there are a number of ways for cross-contamination to occur at food manufacturing plants. Imagine a delivery of carrots entering a facility. After being checked in, they move to the loading dock for inspection, are unloaded and stored in the raw materials area away from possible allergens like wheat flour. When it is time to utilize the carrots, they are walked through the plant along a mapped out path to avoid possible contamination from other materials being used in the production of food at the facility. From there, they are unloaded in a hopper for processing.
Now imagine it’s discovered that a supplier’s driver did not properly wash down its truck before hauling the carrots, and it cannot guarantee that they are not contaminated. Or maybe the employee transporting the carrots from raw materials to the processing line deviated from their route on the way and accidentally walked through an area where nuts are being processed. Or maybe it is discovered that an employee who was previously handling raw meat failed to properly wash their hands or forgot to don gloves before handling the carrots.