In an outbreak that has now run for more than 28 months, at least 279 people across 41 states have fallen ill with multidrug-resistant Salmonella infections linked to raw turkey products. Federal investigators are still trying to determine the cause. In response to food company recalls, more than 150 tons of raw turkey products have flowed back through the supply chain as waste.

In an age when companies envision drone pizza delivery and hamburgers prepared by robots, why is it so hard to locate the source of food-borne diseases like this one?

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