Tsanangurayi Tongesayi, Ph.D., who headed the analysis of rice imported from Asia, Europe and South America, pointed out that imports account for only 7 percent of the rice consumed in the United States. With vast rice fields in Louisiana, California, Texas, Arkansas and Mississippi, the U.S. is a major producer and exporter of the grain. However, imports of rice and rice flour are increasing - by more than 200 percent since 1999 - and rice is the staple food for 3 billion people worldwide, he added.
"Such findings present a situation that is particularly worrisome given that infants and children are especially vulnerable to the effects of lead poisoning," Tongesayi said. "For infants and children, the daily exposure levels from eating the rice products analyzed in this study would be 30-60 times higher than the FDA's provisional total tolerable intake (PTTI) levels. Asians consume more rice, and for these infants and children, exposures would be 60-120 times higher. For adults, the daily exposure levels were 20-40 times higher than the PTTI levels."
The research was part of a symposium titled "Food and Its Environment: What Is In What We Eat?"
Tongesayi's team, which is with Monmouth University in N.J., found that levels of lead in rice imported into the United States ranged from 6 to 12 milligrams/kilogram. From those numbers, they calculated the daily exposure levels for various populations and then made comparisons with the FDA's PTTI levels for lead. They detected the highest amounts of lead in rice from Taiwan and China. Samples from the Czech Republic, Bhutan, Italy, India and Thailand had significantly high levels of lead as well. Analysis of rice samples from Pakistan, Brazil and other countries were still underway.
Because of the increase in rice imports into the United States, Tongesayi said that rice from other nations has made its way into a wide variety of grocery stores, large supermarket chains and restaurants, as well as ethnic specialty markets and restaurants.
Other presentations at the symposium included:
- Inadvertent exposure of chemical toxicants to humans through food: A case for cadmium and lead in rice
Tsanangurayi Tongesayi, Monmouth University
The practice of irrigating crops with untreated industrial and sewage effluents, and freshwater contaminated with leachates from landfills and acid mine drainage, is increasingly becoming one of the major sources of toxic chemicals in the food chain. This is in addition to the extensive use of chemicals in agriculture and the situation of agricultural lands within the vicinity of solid and hazardous waste sites, mining sites and general industrial sites. These practices may be a result of the growing world population which has to be matched by growths in agriculture, industrialization and urbanization. Unfortunately, land not limitless. In this study, we determined the levels the levels of cadmium and lead in rice imported into the U.S. from different regions of the world. The levels of the two elements were significantly higher than the toxicity reference doses of the elements for all age and sex categories. - Manganese and zinc in rice: Unconscious intake of essential elements through non-dietary food sources
Tsanangurayi Tongesayi, Monmouth University
Researchers and regulatory bodies tend to focus more on toxic elements when testing for inorganic chemical pollutants in food. Both toxic and essential elements are increasingly getting into the food chain from contaminated soils and irrigation waters, and a more holistic testing resume must be the standard protocol. Essential elements are really "essential poisons" because they are toxic above certain thresholds. Eating contaminated foods that are considered non-dietary sources of the "essential poisons" may result in an unconscious overdose, especially considering that consumers may be taking food supplements that considered sources of the essential elements. We measured the levels of manganese and zinc in rice, a non-dietary source of manganese and zinc, and found levels that were significantly higher than the recommended daily limits in all the samples. Regardless, the daily limits ignore the fact that exposure from various sources is additive, and having lower levels than recommended limits in one source may not ensure safety. - Analysis of various edible clay supplements and protein powders via energy dispersive X-ray fluorescence spectrometry
Nicholas H Stroeters and Jessica L LaBond, University of Detroit Mercy
The elemental compositions of nine edible clay powder supplements and a dozen protein powders were analyzed using energy dispersive x-ray fluorescence (EDXRF). The samples were from different manufacturers that either harvested clay from a variety of locations around the world or produced protein powders for athletes and dieters. Each product was measured out to five equal samples and all samples were analyzed once. A NIST San Joaquin soil standard (2709) as well as two NIST soil containing lead from paint standards (2586 and 2587) were analyzed to check for instrumental method accuracy. The purpose of the analyses was to look for trace amounts of heavy metals such as: As, Cd, Pb, Hg, Th in the materials. Some clay samples contained detectible amounts of these heavy metals and their significance is further discussed. - US Food and Drug Administration regulation of color additives in food
Julie N. Barrows, U.S. Food and Drug Administration
Color additives are dyes and pigments that impart color to food, drugs, cosmetics, and medical devices. The U.S. Food and Drug Administration (FDA) pre-approves and lists permitted color additives in the Code of Federal Regulations. Color additives have specified use restrictions and purity requirements and some must be batch certified by FDA to control potentially harmful impurities. Certified color additives are required to be declared on food labels by their listed names or appropriate abbreviations, whereas color additives exempt from certification may be declared simply as artificial color. FDA's tools for ensuring compliance with the color additive requirements include warning letters for domestic manufacturers, detentions of imported products, and import alerts. Seizures and injunctions also may be authorized when appropriate.