A rapid method for the nonselective enumeration of Yersinia enterocolitica, a foodborne pathogen associated with pork

An impedance method was developed as a rapid, convenient method to enumerate pure culture of Yersinia enterocolitica. Cultures were incubated in trypticase soy broth (TSB) at 30°C. The BacTrac™ 4000 microorganism growth analyser was used to detect impedance change of TSB representing bacteria cell numbers in the samples. Good correlations with standard plate counts were obtained (r(2)>0.95). This method is also reliable to enumerate Y. enterocolitica growing in biofilms attached to stainless steel. Compared with a standard plate count which involves dislodging biofilms from surfaces, this method is more convenient saving both time and effort. Therefore, it will be useful to study the conditions required for the biofilm growth and control of Y. enterocolitica that could be applied to the pork industry.