John Whitney and Shehryar Ahmad (IMAGE) McMaster University Caption McMaster University researcher John Whitney, left, and PhD candidate Shehryar Ahmad inspect a petri dish with the bacteria that produce the toxin Credit McMaster University Usage Restrictions To be used when reporting on this research License Licensed 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.