Smartphone-based system detects bacteria in food
Is that raw spinach really safe to eat, or is it contaminated? In the near future, an inexpensive device that's linked to your smartphone could warn you of harmful bacteria in your food. The technology is currently being developed at the University of Massachusetts Amherst.
Led by food scientist Dr. Lili He, the researchers have designed a chip that incorporates a molecule known as 3-mercaptophenylboronic acid (3-MBPA), which attracts and binds to bacteria.
The chip gets immersed in a sample of juice or mashed food, and is then rinsed with a high-pH buffer liquid – the latter washes away things like sugars, fats and proteins that came from the food, but leaves any bacteria in place.
Next, the chip is placed in a simple light microscope, of the sort already designed to be used with smartphones. An app then counts the bacteria present on the chip – it can detect as few as 100 bacteria cells per 1 milliliter of solution.
Results are obtained in under two hours. By contrast, the standard method of culturing bacteria from food samples takes two days. While there are other methods of bacteria detection that are quicker than that, He claims that they aren't as sensitive or reliable as her chip.
It is hoped that once the technology is commercially available, it could be used not only by cooks, by also by aid workers at disaster sites who are checking for bacteria in food and water supplies.