Development of membrane filter holder (MFH) method for recovery of heat-injured Escherichia coli O157:H7 and Salmonella typhimurium.
OBJECTIVE
A method of recovering sublethally heat-injured bacteria was developed with specific apparatus (membrane filter holder; MFH) which was originally used for Iso-Grid Hydrophobic membrane. filter holder.


RESULTS
The procedure used a non-selective agar underlayed with a selective medium with a MFH. A non-selective agar was poured on upper part (compartment A) of MFH, and then injured foodborne pathogens were inoculated on the non-selective medium. After 3-h repair incubation period, selective agar was added to the bottom of the chamber (compartment B) of the MFH and further incubated. By diffusing through the non-selective top agar, selective agents from the underlay medium impart selectivity to the system.


CONCLUSIONS
Using the MFH method, recovery of heat-injured foodborne pathogens (Escherichia coli O157:H7 and Salmonella typhimurium) were not different (P > 0.05) from recoveries with non-selective media (TSA). However, the recoveries of foodborne pathogens on MFH were significantly higher (P < 0.05) than those of direct plating on selective medium such as SMAC (MacConkey Sorbitol Agar) or XLD (Xylose Lysine Desoxycholate).


CONCLUSIONS
In conclusion, the MFH method is a simple and convenient method for recovery of heat-injured foodborne pathogens.
Kang
D H
DH
Department of Food Science and Human Nutrition, Washington State University, Pullman, WA 99164-6376, USA. dhkang@wsu.edu
D003470:Culture Media; D019453:Escherichia coli O157 / Q000254:growth & development / Q000302:isolation & purification*; D005374:Filtration; D006358:Hot Temperature; D012486:Salmonella typhimurium / Q000254:growth & development / Q000302:isolation & purification*
D003470:Culture Media