Ever wish you could check your food for health hazards before you cook it, or even leave the supermarket? Well, scientists at Tianjin University of Science and Technology say they have developed a handheld tester that can detect pathogenic bacteria and excessive drug or pesticide residue. The kit, which contains more than 60 strips of indicator paper — one for almost every contaminant listed by the State — works in a matter of minutes, said Wang Shuo, director of the college\'s biotech laboratory. For example, users simply dip the right strip into milk, and if two bars on the paper turn purple, it contains melamine. \"We\'ve put what are likely to be the most popular papers into production first, such as those for melamine and those that test for antibiotics,\" said Wang, adding that the kit is expected to hit the market soon. \"Food safety testing usually requires complex machines and procedures in labs, but this way is much cheaper and faster,\" he said. Unlike the 200 yuan ($32) a lab would charge, he said each test with the kit costs only about 3 yuan. The test is also more accurate, he said. \"Some of the existing tests have a large margin of error, and others can only show negative or positive results. They cannot tell you which particular pesticide or drug is in the food.\" Wang said the research team has obtained 13 national patents for the tester kit and is working on further research to lower the production cost of the paper to make it more affordable for consumers.