Scientists create a cheap device to detect bacteria in food
A group of scientists from the University of Massachusetts at Amherst has created a fast and inexpensive method for detecting bacteria in food and beverages. Developers believe that it will be in demand by people who eat raw food - fresh fruits and vegetables, as well as humanitarian organizations working in the field after natural disasters.
“Most people around the world cook vegetables before eating, but in the US, many people prefer to eat them raw. This gave us the idea of creating a quick test that can be done at home, ”the developers said in an article published on the website of the University of Massachusetts in Amherst. The problem is also relevant because today there are bacteria that are resistant to all popular antibiotics .
Usually, the method of sowing is used to count the number of bacteria, which takes about two days. There are faster, but less reliable ways. The new chip interacts only with bacteria, but not with sugars, fats, proteins or dirt in food.
The new device uses a two-step method for the detection of bacteria: optical and chemical testing. A designed chip is able to find bacteria on the surface of solid food, for example, on spinach leaves, and in liquids like apple juice. The optical method involves the detection of 3-mercaptophenylboronic acid, which binds to any bacteria. Food components are cleaned with a high pH demasking buffer, leaving the bacteria to quantify using a microscope for a smartphone and an application. The sensitivity of the method makes it possible to detect even 100 bacteria per 1 milliliter, while other “fast” solutions are able to find bacteria with their number not less than 10,000 per 1 ml.
The chemical method uses surface-enhanced Raman spectroscopy (SERS) , a technology that helps identify cancer cells among a large number of healthy ones and distinguish fake pictures from real ones. The technology is based on the analysis of the reflected from the material of the laser beams with a variable wavelength.
Scientists report that already last summer they tested an optical method for detecting bacteria for possible home use with a microscope for a smartphone, which costs about $ 30. A smartphone application developed by the student. Development is in the process of patenting.
The scientific article was published in the journal Food Microbiology (DOI: 10.1016 / j.fm.2017.11.007).
“Most people around the world cook vegetables before eating, but in the US, many people prefer to eat them raw. This gave us the idea of creating a quick test that can be done at home, ”the developers said in an article published on the website of the University of Massachusetts in Amherst. The problem is also relevant because today there are bacteria that are resistant to all popular antibiotics .
Usually, the method of sowing is used to count the number of bacteria, which takes about two days. There are faster, but less reliable ways. The new chip interacts only with bacteria, but not with sugars, fats, proteins or dirt in food.
The new device uses a two-step method for the detection of bacteria: optical and chemical testing. A designed chip is able to find bacteria on the surface of solid food, for example, on spinach leaves, and in liquids like apple juice. The optical method involves the detection of 3-mercaptophenylboronic acid, which binds to any bacteria. Food components are cleaned with a high pH demasking buffer, leaving the bacteria to quantify using a microscope for a smartphone and an application. The sensitivity of the method makes it possible to detect even 100 bacteria per 1 milliliter, while other “fast” solutions are able to find bacteria with their number not less than 10,000 per 1 ml.
The chemical method uses surface-enhanced Raman spectroscopy (SERS) , a technology that helps identify cancer cells among a large number of healthy ones and distinguish fake pictures from real ones. The technology is based on the analysis of the reflected from the material of the laser beams with a variable wavelength.
Scientists report that already last summer they tested an optical method for detecting bacteria for possible home use with a microscope for a smartphone, which costs about $ 30. A smartphone application developed by the student. Development is in the process of patenting.
The scientific article was published in the journal Food Microbiology (DOI: 10.1016 / j.fm.2017.11.007).
Source: https://habr.com/ru/post/409869/