Michigan State University researchers have found that sunflower seeds are frequently contaminated with a toxin produced by molds and pose an increased health risk in a number of low-income countries worldwide.

A team of scientists documented the frequent instances of a toxin called aflatoxin, produced by Aspergillus molds, found in sunflower seeds and their products. Aspergillus molds commonly infect corn, peanuts, pistachios and almonds.

This study, published in the current issue of PLoS ONE, is one of the first to associate the aflatoxin contamination with sunflower seeds. The study was conducted in Tanzania, but according to researchers, this is by no means an isolated issue. Chronic exposure to aflatoxin causes an estimated 25,000-155,000 deaths worldwide each year from just corn and peanuts alone.

Aflatoxin is known as one of the most potent liver carcinogens. The research to detect and limit its presence in sunflower seeds and their products could save lives and reduce liver disease in areas where sunflower and sunflower byproducts are consumed, said Gale Strasburg, MSU food science and human nutrition professor and one of the study's co-authors.

The high levels of aflatoxin in a commodity frequently consumed by the Tanzanian population indicates to local authorities that an intervention system must be implemented to prevent and control contamination among the value chain and enhance food and feed safety.

“Follow-up research is needed to determine intake rates of sunflower seed products in humans and animals, to inform exposure assessments and to better understand the role of sunflower seeds and cakes as a dietary aflatoxin source,” Strasburg said.

Farmers in Tanzania grow sunflowers for the seeds the sell them to local millers who press them for oil and sell to consumers for cooking. The remaining sunflower seed cakes are used as animal feed.

The seeds become infected by types of Aspergillus molds, which produce the toxins. This contamination has been well studied in other crops, but not in sunflower seeds. Juma Mmongoyo, a former MSU food science doctoral student and lead author of the study, analyzed aflatoxin levels of seeds and cakes in seven regions of Tanzania in 2014 and 2015.

A micrograph of an Aspergillus spore, a type of fungus that produces cancer-causing aflatoxin.

Mmongoyo found that nearly 60-percent of seed samples and 80-percent of cake samples were contaminated with aflatoxins. In addition, only 14-percent of seeds and 17-percent of cakes were contaminated with more than 20 parts per billion -- the level considered safe by the U.S. Food and Drug Administration. Some samples had levels of several hundred parts per billion.

“Billions of people worldwide are exposed to aflatoxin in their diets, particularly in places where food is not monitored regularly for contaminants,” said Felicia Wu, the Hannah Distinguished Professor of Food Science and Human Nutrition and Agricultural, Food and Resource Economics at MSU and study co-author.

“Our previous work with the World Health Organization on the global burden of foodborne disease showed that aflatoxin is one of the chemical contaminants that causes the greatest disease burden worldwide.”

Wu founded the Center for Health Impacts of Agriculture, which tackles global issues, such as antibiotics given to livestock and poultry that seek into soil and nearby bodies of water and the associated between malaria incidences and irrigation patterns in sub-Saharan Africa.

For more information about the study, click here.

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April Stevens is a multi-platform producer at WZZM 13. Have a news tip? Email news@wzzm13.com, visit our Facebook page or Twitter.