Fung’s Double Tube Leads Way to Quicker Pathogen Detection

When government and industry were looking for a way to identify more rapidly the presence of the pathogenicClostridium perfringens bacterium in food and water, Daniel Fung of Kansas State University realized he had a potential solution on his shelf. He applied what’s known as the Fung Double Tube method that he developed decades earlier and determined that the detection time can be reduced from about a day or two down to four hours.

“In the meat industry and related food industries, the faster one can detect and enumerate live major pathogens such asC. perfringens, the faster corrective actions can be implemented or the food can be destroyed before reaching the consumers,” said Fung, a food science professor who researched the issue as a Food Safety Consortium-supported project. “The benefit of a rapid method to detect and enumerate live C. perfringens in foods in four hours is obvious.”

The Fung Double Tube method is relatively easy to implement. The system uses one large tube and one small tube. Insert the small tube into the larger tube that holds a water sample. Then add a specially melted agar – a gelatin-like product used for solidifying culture media as a thickening agent – to create a thin layer between the two tubes that will grow C. perfringens. The unit is then placed in an incubator at 42 degrees C.

“The system makes anaerobic microbiology very simple,” Fung said. “One can see a C. perfringens colony in the Double tube in about four to five hours. We can know in five to six hours how many living colonies of C. perfringens per milliliter of water there are. That is a major improvement and it’s so cheap.”

The system works well for water testing, but more research is necessary to prepare it for use in the food industry. Fung’s research team is examining how to apply it for use with ground beef so the meat won’t have to be incubated overnight before pathogen counts can be obtained.