Complex Global Connections Complicate Food Investigations

In a first-of-its-kind study, a team of researchers that includes a physicist, a mathematician, and an economist have used food import and export databases to create a map of the worldwide food transport network.

Using network science methods, the scientists, led by József Baranyi, PhD, of the UK-based Institute of Food Research, identified a number of global “hotspots” central to the food network. Because of the specific dynamics of their food traffic, these “hotspots” are also particularly vulnerable to outbreaks, and the complexity of the incoming and outgoing shipments make the tracing of outbreaks particularly difficult. Their findings appeared in the journal PLoS ONE.

The Netherlands proved to be one of the most significant areas of “food flux.” “Inevitably, any sort of randomly organized network forms around certain hubs,” said Dr. Baranyi. “A country like the Netherlands acts as a sort of ‘lazy susan’—a lot of things are coming in, and a lot of things are going out. If I were to randomly pick any two countries in the world and ask which third country is most likely to have food going from country one to country two pass through it, that country would be the Netherlands.”

By contrast, Dr. Baranyi compared the Netherlands with a country like Singapore, which has a similarly high level of food traffic but is not considered a hot spot. “Both the Singapore Harbor and Rotterdam Harbor have something like 200,000 vehicles going through every year, more than 70% of them carrying food,” he noted. “But the difference is that a lot of the foods coming through Rotterdam have come through many other countries first, and when they leave Rotterdam, they go not only to the next country but two or three countries further.”

In Singapore, on the other hand, the food travels primarily around Asia, with far fewer hops. “In the Netherlands, as well as countries like Germany, the U.S., and France, there is a good chance that much of the food comes from a country which imported it from another country, which imported it from another country, and so on. This is what makes outbreak tracing difficult.”

Dr. Baranyi pointed to the German E. coli outbreak of 2011, ultimately traced to contaminated sprouts, as an example: “First they blamed Spanish cucumbers, and then it turned out that originally the seed came from Egypt and the actual sprout was local to Germany. But because there were so many countries exporting foods in this channel, it took two weeks to trace it back—and by that time 14 people had died.”

The paper is available online.

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