New Rapid Test for Salmonella

“Newer, faster, better” are the keywords in bacteria detection R&D these days. And no one seems to be doing it faster or better than researchers at the University of Arkansas, who recently announced they had discovered a way to detect as few as 5,000 Salmonella bacteria from a chicken carcass sample in a mere two hours. The rapid test is being developed as a joint project by UA poultry science professors Yanbin Li and Michael Slavik, and chemistry professor David Paul, who are pooling their expertise in bacteriology, food processing and micro sensors to create a new, faster breed of biosensor capable of detecting potentially deadly bacteria in the processing plant environment.

According to a UA press release, the process entails creating a “Chicken soup” by shaking a chicken carcass in a plastic bag containing a buffer. This mixture is poured into a test tube filed with small magnetic beads coated with antibodies that bind a specific Salmonella strain. The mixture is then washed with a second buffer, using a magnet to attract the beads that have Salmonella bound to the antibody. An enzyme is then added which attaches to the S. typhimurium bacteria, and phenyl phosphate is added to the mixture. At this point the enzyme attached to the bacteria chops up the phenyl phosphate to create phenol, which can be detected by an electrode. The reaction takes place in less than an hour, with the amount of phenol produced being in direct proportion to the amount of bacteria in the sample. Using this method, as few at 5,000 bacteria can reportedly be detected in two hours using an electrode the size of a pen.