Khengdauliu Chawang (IMAGE) Southern Methodist University Caption SMU graduate student Khengdauliu Chawang has developed a miniature pH sensor that can tell when food has spoiled in real time. Creating the device was personal for Chawang. Credit SMU Usage Restrictions No restrictions 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.