“There are two primary reasons for the recent uptick in announcements of tainted food. One, the US food system has become extremely complicated in recent decades: There are more imported foods now as well as more highly processed foods, which creates more opportunities for disease to enter the food system.
Two, the government has better and faster tracing capabilities, thanks to legislation around food safety modernization. That makes it easier for the Food and Drug Administration, one of the bodies that investigates such outbreaks, to track problems to their source. It also makes it easier for companies to recall tainted products before they spread further into the food system and sicken large numbers of people. (The US Department of Agriculture oversees recalls of meat, poultry, and eggs as well, but it’s not subject to this legislation.)”
https://www.vox.com/food/379474/mcdonalds-e-coli-boars-head-listeria-salmonella-outbreak