Food scientists at the University of Missouri have developed a method that uses DNA for simultaneous detection of three pathogens commonly found in meat, according to a University of Missouri news release.
Azlin Mustapha, University of Missouri assistant professor of food science and Yong Li, MU graduate assistant, have developed a technique that takes only a day or two, as opposed to a week.
The scientists use a gene sequence that can be found in three pathogenic bacteria commonly found in meat: E. coli, Salmonella and Shigella. They have devised a test that uses DNA extraction and amplification to detect the presence of all three bacteria simultaneously.
After as little as six to eight hours, they could extract and amplify the DNA from the three bacteria in the beef samples and observe them on a 2-percent agarose gel. Stained with a fluorescent dye and exposed to ultraviolet light, "this shows the presence of these bacteria," Li said.
Mustapha said the next step is to test the technique on pork and chicken. If it works as she expects, "it does have potential as a valuable tool. It could be made into an automated processing machine" for large-scale applications in the food industry.
Previous research had isolated a gene, phoP, (pronounced FOE-pee) from Salmonella, whose DNA sequence is homologous to that of the phoP gene in Shigella and a harmless form of E. coli. The MU scientists found identical sequences of phoP also exist in E. coli 0157:H7 – "the dangerous one," Mustapha said. "We found out that this method could also detect this scary bug."
Both researchers believe their technique has the potential to change the way the food industry tests meat for the presence of bacteria. "These bacteria are very important in the U.S.A.," Li said. "If we can detect them all at the same time, it will reduce detection time and costs. We think it will work not just on beef but also on pork and maybe chicken and other poultry products."
University of Missouri