In a country as big as the United States, you might expect food to travel hundreds of miles before it reaches the dinner table. But the first-ever map of America’s food supply chain shows some commodities never leave the county in which they were produced.
A team at the University of Illinois used official data to create a detailed map of food journeys in the US. It shows 9.5 million food transit routes, underlining the complexity of the nation’s food supply network.
One food journey tracked by the study follows corn grown on an Illinois farm to a grain silo in Iowa, from where it is transported to feed cows in Kansas. After processing, the meat products then make their way back to Illinois and onto the shelves of a grocery store in Chicago.
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The study shows California is home to the US’s largest food processors, with Los Angeles County receiving 21.9 million tonnes of food in 2012, the year the researchers examined. Some of the food arriving in LA was for local consumption, though the county shipped out 16.6 million tonnes.
But some food does not travel very far at all. In the case of California, food-growing areas are close to processing facilities in and around the bigger cities, so food can be produced, processed and sold locally.
Some of the largest food flows in the US are within California, as food moves between farms and processors. For example, milk was tracked from farm to the dairy processing facility where it was made into yogurt, before being sent to a supermarket distribution centre - all within the same county.
The US Department of Agriculture is spending $23 million a year on grants to encourage local food production. US consumer spending on locally-grown food increased from $5 billion in 2008 to $12 billion in 2014, and is forecast to reach $20 billion this year.
As well as showing how far food travels, the study also identifies core transshipment hubs that are vital to food security. The authors say disruption to any one of these hubs - located in California, Arizona, Tennessee and Texas - could cause shortages across the country.
Methods used to move food around the US vary according to the commodity. America is the world’s biggest grain producer and railroads distribute much of the more than 400 million tonnes produced annually.
The Ohio and Mississippi rivers are also major grain arteries, with barges moving the crop from the Midwest to New Orleans for export. But problems with some of the locks on the Mississippi are creating serious bottlenecks, slowing shipments.
“The infrastructure along these waterways [is] critical, but [has] not been overhauled since their construction in 1929. If they were to fail entirely, then commodity transport and supply chains would be completely disrupted,” according to study author Megan Konar.