Cell phones have already revolutionized communication, and now they might one day do the same for food safety. A research group working under Aydogan Ozcan at UCLA has created a cell phone attachment that can calculate the concentration of E. coli in a liquid sample. The device works similarly to a fluorescence microscope, pumping the sample into a series of small tubes treated with E. coli antibodies, then measuring the excitement of quantum dots (small fragments of semiconductors) placed around them with the phone’s camera and an additional lens. From this excitement, researchers can calculate the concentration of E. coli in the sample. The method was tested successfully both in a specially-prepared solution and in a glass of milk.