Objective: To introduce green fluorescence protein (GFP) into E. coli O157:H7 and improve the detection methods for this bacteria, and to study the kinetics of E. coli O157:H7.
Methods: The plasmid pGFP was transferred into E. coli O157:H7. The characteristic of the new built O157:H7-pGFP strain was evaluated. Some food samples were inoculated with the recombinant strain under certain temperature to imitate different storage circumstances. The contaminated E. coli O157:H7 were counted after certain time.
Results: The pGFP was stable in E. coli O157:H7. The E. coli O157:H7-pGFP inoculated in ground poultry meat and pasteurized milk were enriched to 35 000 approximately 200 000 times in 12 h under higher storage temperature (37 degrees C), whereas the quantity decreased slowly under lower temperature (4 degrees C).
Conclusion: The recombinant strain with the characters of ampicillin resistance and green fluorescence under UV 365 nm was a useful tool in detection methods improvement and bacteria survival studies.