As the world's population climbs past 7 billion, and with demand for food to increase by 50% by 2030, the sustainable production and distribution of food must be balanced against the need to ensure its chemical and microbiological safety, warn researchers in PLoS ONE.
The study – a ‘rigorous analysis’ of the international food-trade network (IFTN) – reveals that the network is vulnerable to the fast spread of contaminants, and reports on the correlation between known food poisoning outbreaks and the centrality of countries on the network.
“Using UN databases, here we show that the international agro-food trade network (IFTN) … has evolved into a highly heterogeneous, complex supply-chain network,” say the researchers, led by senior author Dr József Baranyi – from the Institute of Food Research in the U.K.
“Graph theoretical analysis and a dynamic food flux model show that the IFTN provides a vehicle suitable for the fast distribution of potential contaminants but unsuitable for tracing their origin,” they added.
Too complex?
The research maps the highly complex network that is formed around a core group of seven countries, each trading with more than 77% of the world's nations.
Since any two countries in the IFTN have only two degrees of separation on the network, the IFTN is capable of spreading a foodborne contaminant very efficiently, say Baranyi and his colleagues
The system also tends to mask the contaminant's origins once the system is compromised, since so many network paths run through the central nodes, they note.
“In particular, we show that high values of node betweenness and vulnerability correlate well with recorded large food poisoning outbreaks,” reveal the researchers.
“During a food poisoning outbreak the first and most important task is to identify the origin of the contamination … Delays in this task can have severe consequences for the health of the population and incur social, political and economical damages with international repercussions.”
Longer delays?
A case in point is the consequences of the three weeks delay in identifying the origin of the E. coli contamination in Germany in June 2011, they say – noting that the increasing complexity of the network will mean even longer delays in tracing the origin of poisoning outbreaks or the source of contaminants in the future.
“Note that our study does not predict an increase in the number of food poisoning cases but that, when it happens, there will be inevitable delays in identifying the sources due to the increasingly interwoven nature of the IFTN … That is, even if food contamination was less frequent … its dispersion/spread is becoming more efficient.”
Better understanding
Baranyi and his colleagues noted recent calls for an interdisciplinary approach “to monitor, understand, and control food trade flows as it becomes an issue no longer affecting just single countries, but the global livelihood of the human population.”
The authors suggested that such an approach would enable better understanding of the international food trade network: “especially if it is broken down into time-scales, food types and their interdependencies.”
“Such an interdisciplinary approach is entirely within the means of the state-of-the art of science and technology, if supported by detailed and systematic data collection.”
The team said international organisations, such as the United Nations and the European Union, are essential to any effort to collect and monitor data on the network
Source: PLoS ONE
Published online ahead of print, doi: 10.1371/journal.pone.0037810
“Complexity of the International Agro-Food Trade Network and Its Impact on Food Safety”
Authors: Ercsey-Ravasz M, Toroczkai Z, Lakner Z, Baranyi J.