Social network analysis of global trade patterns for corn shows that the food safety regulations imposed by national governments are an indicator of how countries organize themselves for trade, according to new research from the University of Pittsburgh Graduate School of Public Health.
The results, published today in PLOS ONE, the journal of the Public Library of Science, mean that nations should carefully consider how establishing or changing their food safety laws could influence global trade.
“Like attracts like. Nations with similar food safety regulations tend to trade more with each other, which could have important policy implications,” said lead author Felicia Wu, Ph.D., associate professor in Pitt Public Health’s Department of Environmental and Occupational Health.
The idea for the research grew from a comment made by former United Nations Secretary-General Kofi Annan in 2001 when he said that the European Union’s strict regulation on allowable amounts of a cancer-causing contaminant in food was causing Africa to lose $670 million in trade every year. Dr. Wu was interested in examining whether this statement holds true for trade today.
Aflatoxin is produced by fungi that grow on corn, peanuts and tree nuts. This toxin, when consumed in large quantities or small amounts over time, causes liver cancer. To avoid dangerous levels of contamination, countries regulate the level of aflatoxin allowed in food.
The U.S. Food and Drug Administration allows up to 20 micrograms of aflatoxin per kilogram of corn – or 20 parts per billion. The European Union has some of the most stringent aflatoxin food safety standards, allowing only 4 micrograms per kilogram of corn, while China allows 10 times as much at 40 micrograms per kilogram. The majority of African countries do not regulate aflatoxin levels in corn.
Dr. Wu and her co-author, Hasan Guclu, Ph.D., assistant professor of biostatistics at Pitt Public Health, found three main corn trade clusters, or networks. The United States -- by far the largest exporter of corn worldwide -- is at the center of one cluster. European countries make up another, while Argentina, China and Brazil are at the center of the last large network.
The common thread linking the clusters was their aflatoxin standard.
“The question becomes which came first, the chicken or the egg?” Dr. Wu said. “Were the regulations in place first and the trading patterns established because of them? Or were the trading patterns in place first and the regulations were set based upon who was already trading with whom? The answer could have important implications to nations considering new food safety regulations.”
Social network analysis is a popular technique typically used to learn more about interactions and relationships among individuals. These networks are shown with a web-like diagram where interactions are indicated by lines that tie individuals, represented by points, together. As an individual becomes increasingly tied to others, a cluster can form to reveal an influential interaction.
Drs. Wu and Guclu are creating social network models that can look at the development of trade patterns and regulation enactment over time in an effort to further explore the relationship between food safety laws and global trade.
“If the specific trade community determines food safety regulations in multiple nations, then certain nations in the network have a large amount of power in determining regulations worldwide,” Dr. Wu said. “However, if regulations determine trade patterns, then nations should be aware of the implication their standard-setting will have on who their future trading partners will be.”
The complete article will be available through PLOS at http://dx.plos.org/10.1371/journal.pone.0045151.
This work was funded by the National Cancer Institute of the National Institutes of Health grant 5R01CA153073-2.