Sunflower seeds and products made from them are often contaminated with a toxin produced by molds, report researchers. This poses an increased health risk in many low-income countries worldwide.
In a new study, a team of scientists documented frequent occurrence of aflatoxin—a toxin produced by Aspergillus molds that commonly infect corn, peanuts, pistachios, and almonds—in sunflower seeds and their products. The study, published in PLOS ONE, is one of the first to associate aflatoxin contamination with sunflower seeds.
The study took place in Tanzania, but the problem is by no means isolated there. Chronic exposure to aflatoxin causes an estimated 25,000-155,000 deaths worldwide each year from corn and peanuts alone.
Since it is one of the most potent liver carcinogens known, the research to detect and limit its presence in sunflower seeds and their products could help save lives and reduce liver disease in areas where people eat sunflowers and their byproducts, says coauthor Gale Strasburg, a food science and human nutrition professor at Michigan State University.
“These high aflatoxin levels, in a commodity frequently consumed by the Tanzanian population, indicate that local authorities must implement interventions to prevent and control aflatoxin contamination along the sunflower commodity value chain, to enhance food and feed safety in Tanzania,” says Strasburg.
“Billions of people worldwide are exposed to aflatoxin in their diets, particularly in places where food is not monitored regularly for contaminants…”
“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,” he adds.
Smallholder farmers in Tanzania grow sunflowers for the seeds, which they sell to local millers who press the seeds for oil to sell to local consumers for cooking. People use the remaining cakes as animal feed.
The seeds become infected by Aspergillus flavus or Aspergillus parasiticus, molds that produce aflatoxin. This contamination has been well studied in other crops, but there is little research published on sunflower seed contamination.
Juma Mmongoyo, a former 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. Nearly 60 percent of seed samples and 80 percent of cake samples were contaminated with aflatoxins.
In addition, 14 percent of seeds and 17 percent of cakes were contaminated above 20 parts per billion, the level considered safe by the US 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,” says Felicia Wu, study coauthor.
“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,” she adds.
To help solve that problem, Wu founded the Center for the Health Impacts of Agriculture. The center tackles global issues, such as antibiotics given to livestock and poultry that seep into soil and nearby bodies of water, and the association between malaria incidence and irrigation patterns in sub-Saharan Africa.
Additional researchers from Michigan State and the Sokoine University of Agriculture in Tanzania also contributed to this research.
Source: Michigan State University