U.S. researchers say organic brown rice syrup may be a hidden source of arsenic in food ranging from infant formula to energy bars. Brown rice syrup is used in organic food products as a preferred alternative to high fructose corn syrup. Dartmouth researchers, who had previously called attention to the potential for harmful levels of inorganic arsenic in rice, say brown rice syrup can also be a major source of arsenic. One organic infant milk formula containing brown rice syrup had as much as six times the Environmental Protection Agency's safe drinking water limit of 10 parts per billion for total arsenic, researchers said. Cereal bars and high-energy foods containing organic brown rice syrup also had higher arsenic concentrations than those without the syrup, the Hanover, N.H., college said Thursday. None of the products was identified by name. Brian Jackson, director of the Trace Element Analysis Core Facility at Dartmouth and a member of the college's Superfund Research Program, is lead author on the study published Thursday in the journal Environmental Health Perspectives. Jackson and his colleagues tested 17 infant formulas, 29 cereal bars and three energy gel "shots" purchased from local stores. Of the 17 formulas tested, only two had listed organic brown rice syrup as the primary ingredient. Researchers said these two formulas were extremely high in arsenic. The amount of inorganic arsenic, which is more toxic than organic arsenic, averaged 8.6 parts per billion for the dairy formula and 21.4 parts per billion for the soy formula. The researchers said the findings suggest an urgent need for regulatory limits on arsenic in food.