A rapid, sensitive, and inexpensive test for the presence of E. coli O157:H7 in food samples has been developed in the United States. This strain of E. coli can live on food and cause severe intestinal infections. The main component of the test system is a genetically modified bacteriophage that glows in the presence of the target bacterium, E. coli. The technology was developed at Purdue University (Indiana, USA).

How does the test work? Vegetables or other products to be tested are washed with water, then this water is mixed with a solution containing bacteriophages, and the resulting mixture is incubated for several hours. If the samples contain the target bacteria, the phages penetrate them and, when the substrate is added, they begin to glow. The glow can be recorded using a miniature luminometer or a smartphone camera with the appropriate app installed. The app will also indicate whether the sample contains pathogenic E. coli.

Similar tests can detect other pathogens that cause intestinal infections, including salmonella and listeria, without special equipment or expensive reagents.