Though oats are often touted for boosting heart heath, scientists warn that the grain and its products might need closer monitoring for potential mold contamination, according to a recent study.

Researchers found that some oat-based breakfast cereals in the United States contain a mold-related toxin called ochratoxin A (OTA) that's been linked to kidney cancer in animal studies. The findings could have implications for consumer health.

Dojin Ryu and Hyun Jung Lee note that OTA is one of the most common toxic products released by molds in the world.

Previous studies have found the toxin in samples of pork, dried fruits, wine, coffee and other products. Scientists don't yet know how the toxin affects human health, but the International Agency for Research on Cancer, which is part of the World Health Organization, classifies it as a possible human carcinogen. Animals exposed to OTA in experiments developed kidney tumors. Although the U.S. doesn't currently regulate the contaminant, the European Union has set maximum limits for OTA in food. Ryu and Lee wanted to see how U.S. breakfast cereals -- a staple in many Americans' diets -- measured up to that standard.

For the study, researchers tested close to 500 samples of corn-, rice-, wheat- and oat-based breakfast cereals purchased from U.S. stores over two years. They found that in most samples, OTA levels were lower than the European threshold. But concentrations exceeded the EU standard in 8 percent of oat-based breakfast cereal samples. The researchers conclude that oat production, storage and processing need careful review to better protect consumer health.

The findings are detailed in the ACS'Journal of Agricultural and Food Chemistry.