In this digital age, ruled by smartphone apps, how about one to tell you how fresh your milk is? Although there are stringent safety rules concerning the quality of milk, almost 68% of what is available in the country does not conform to them. In a recent study, researchers at the Indian Institute of Technology Guwahati have come up with a paper-based detection system to detect if a sample of milk is pasteurised and fresh. This technique, they say, is cost-effective, rapid, user- and environment-friendly.