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.

He said that despite the need for quick food safety testing, it is hardly possible to work out a universal testing paper that can detect all contaminants.

"We can only detect certain contaminants already known to us, instead of randomly testing what producers have put into food samples," said Wang, who started the project in 2003.

Although he sees a huge potential market for the product, the intention of the research was to help food safety watchdogs quickly find substandard food.

"The potential market of the testing paper shows the public's lack of confidence in food safety," he said.

Since melamine-tainted milk killed six infants and poisoned more than 300,000 others in 2008, a spate of food scandals has sparked fear in China's food safety supervision system and dented the confidence in food quality.

China's latest baby formula scandal, in which Swiss milk brand Hero Nutradefense is suspected of providing substandard products, has added another entry on the long list.

The huge potential market has prompted many professionals like Wang to focus on researching measures to test fast food safety.

Lou Xinhui, a chemistry professor at Capital Normal University in Beijing, has worked out a fast testing solution for mercury, a heavy metal that can be absorbed by plants if the water and soil are already contaminated.

Lou said her research can detect lead, arsenic and mercury in about an hour, and can be used by manufacturers for preliminary screening and by the safety watchdog for quickly monitoring food.

"The method is similar to the test we do at hospitals for hepatitis B, but is more complicated."

Lou argued that using a chip to test heavy metals is much more accurate than test papers, since its dynamic range is larger.

Liu Qinghui, an engineer in Beijing, said he wouldn't mind trying the test paper if it comes out.

"It sounds cheap and fast, but I suspect the accuracy of such testing," he said. "The way that customers operate the test paper, as well as the environment, such as temperature and humidity, all affect the results."

Lin Lijun, director of the Tianjin Food and Drug Administration, said it would be possible to use such quick testing methods if they prove effective.

zhaoyinan@chinadaily.com.cn

(China Daily 04/02/2013 page1)