How can you tell if food labeled as organic truly is organic, that is, grown without synthetic fertilizers and pesticides? Live Science reports that Scientists in Spain, trusting chemistry more than corporations, are developing a method to sniff out food grown with synthetic fertilizers. Their technique, published in the January-February issue of the Journal of Environmental Quality, relies on the detection of an isotope of nitrogen found in organic food but not in non-organic food.
Atmospheric nitrogen is made mostly from the nitrogen-14 isotope, with seven protons and seven neutrons. There’s virtually no isotope nitrogen-15 in the air nor, as a result, in the manufactured nitrate-based fertilizers. However, the nitrogen in manure, the primary fertilizer used in organic farming, can contain up to 20 percent nitrogen-15, according to the researchers, led by Francisco del Amor of the Instituto Murciano de Investigación y Desarrollo Agrario y Agrario y Alimentario (IMIDA) in Murcia, Spain in a joint project with the Institute of Agrobiotechnology (UPNA-CSIC) .
Plants suck up nitrogen, so organic fruits and vegetables are loaded with nitrogen-15. Any food with no nitrogen-15 or a low N15/N14 ratio betrays the use of synthetic fertilizers.
The Spanish researchers, who used sweet pepper plants in their study, said someday their method could be useful in detecting small amounts of synthetic fertilizers used by organic farmers worried about low nitrogen levels in the soil and thus the potential for a low-yield harvest. As organic farming goes global, isotope sniffers could be used by nations to monitor the integrity of imported organic food.