Glowing bacteria (IMAGE) Purdue University Caption New, faster test for pathogenic E. coli in beef is based on using a modified phage, a virus that infects bacteria. After infecting the pathogenic E. coli, the phage produces an enzyme that causes the bacteria to glow. Credit Purdue Agricultural Communications photo/Tom Campbell Usage Restrictions This image may be used by news organizations in reports referencing Purdue University’s E. coli assay for rapid testing of raw beef. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.