FOOD SAFETY & QUALITY
Arsenic is well-known for its intentional use as a poison. Fans of the 1944 comedy film Arsenic and Old Lace may remember that the Brewster sisters used it in their homemade elderberry wine to murder lonely old men. But arsenic also occurs naturally in various foods, such as rice, because it is found naturally in the environment. Arsenic is an odorless and tasteless element that enters water and crops from natural deposits in the earth as well as from agricultural and industrial practices, including use of arsenical pesticides/herbicides (most of which are no longer in use), fertilizers, irrigation, burning of fossil fuels, and disposal of industrial and animal waste. It is a known carcinogen and causes other health problems. The U.S. Environmental Protection Agency (EPA) has set a limit of 10 ppb for arsenic in drinking water to protect consumers from the effects of long-term, chronic exposure to arsenic. The U.S. Food and Drug Administration (FDA) has the same standard for bottled water but has set no limit for arsenic in foods.
Rice, a staple crop grown around the world, is the second-highest source of arsenic in the American diet (seafood is the highest). According to Steve Hensley, Senior Director of Regulatory Affairs, USA Rice Federation, rice is the single crop that has the highest average arsenic content (although vegetables as a group contribute more arsenic). Arsenic is absorbed from soil or water and concentrated in the outer layers of rice as it grows. Since white rice is produced by removing the surface layers, it tends to have lower arsenic levels on average than brown rice, of which only the hull is removed.
Hensley said that the United States produces 2% of the world’s annual rice supply but is the world’s third-largest exporter of rice, sending 50% of annual production to overseas customers. Eighty-five percent of the rice consumed in the United States is grown in the United States. Rice farmers in Arkansas, California, Louisiana, Mississippi, Missouri, and Texas produce more than 20 billion pounds of rice each year, including long-, medium-, and short-grain types as well as aromatic and specialty types.
Arsenic Levels Surveyed
Various organizations have surveyed the levels of arsenic in rice and other foods. Consumers Union reported in its November 2012 issue of Consumer Reports that its tests showed that rice products on grocery shelves contain arsenic, many at worrisome levels, and recommended that consumers consider limiting their consumption of rice products.
The FDA has been measuring arsenic in food commodities for more than 20 years through its Total Diet Study (TDS), according to Nega Beru, Director of the FDA’s Office of Food Safety. Arsenic occurs in both organic and inorganic forms, with the organic considered much less harmful than the inorganic forms, but the TDS analyzed products for only total arsenic content. Beginning in 2011, he said, the agency began sampling and analyzing rice and rice products for total arsenic content as well as organic and inorganic contents and posted the results for about 200 samples in September 2012. The agency then performed additional sampling and testing, and in September 2013 the agency posted the results for approximately 1,300 samples of rice and rice products. The FDA concluded that the amount of detectable arsenic was too low in the rice and rice product samples to cause any immediate or short-term adverse health effects and recommended that consumers eat a well-balanced diet for good nutrition and to minimize potential adverse consequences from consuming an excess of any one food. The FDA said that it has seen no evidence of change in levels of total arsenic in foods over the more than 20 years of the TDS.
Since technology is now available that provides greater specificity about the different types of arsenic present in foods, Beru said, the agency’s next step is to use these new tools to consider long-term exposure to very low amounts of arsenic in rice and rice products. He said that the agency is working to assess the potential health risk from long-term exposure to the arsenic in rice and rice products and to determine how much arsenic is consumed from rice and rice products and whether health effects differ among segments of the population. FDA scientists at the Center for Food Safety and Applied Nutrition, in consultation with colleagues in the FDA’s National Center for Toxicological Research, the National Institute of Environmental Health Sciences, and the EPA are conducting a risk assessment. Toxicologists will be looking at the data on possible different adverse effects from arsenic exposure in rice, nutritionists will be studying rice consumption patterns, and epidemiologists will be looking for patterns of disease. At the same time, Beru said, the rice industry, university researchers, and the U.S. Dept. of Agriculture will be working to identify ways to possibly reduce arsenic levels in rice during production.