EVALUATION OF MODIFIED MOORE SWAB AND TANGENTIAL FLOW FILTRATION FOR CONCENTRATION OF Salmonella Spp AND Escherichia coli O157:H7 FROM LARGES VOLUMES OF WATER
This study evaluated and compared the efficacy of for concentration and subsequent detection of Escherichia coli O157:H7 and Salmonella Spp fromlarge volumes of water (10L). The objective this study was evaluate the efficacy of two filters Modified Moore Swabs (MMS) and Tangential Flow Filtration(TFF) methods for concentrations of E. coliO157:H7 and Salmonella Spp in a saline model system for agricultural and produce wash water. The cocktail of E. coli was prepared in three different strains like the cocktail of Salmonella Spp. Thecocktail was prepared, put on plates TSA+AMP (Trypticase Soy Agar and Ampicillin 20mg/L) for 24h/37°C. After 1 µL was inoculated in TSB+AMP (Trypticase Soy Broth and Ampicillin 20mg/L) for 24h/37°C. Afterthis, was take 1 mL each E. coli Spp or Salmonella Spp, put in Vortex ® for 10 seconds. Inoculum levels used were:10¹,10²,10³ and 104 CFU/100mL. One mL of inoculum in lambda buffer was added to 10 Lof non-sterile normal saline. TFF was conduced using mode Kros Flo® to a final volume ~250mL. MMS was prepared by inserting into a cartridge (PVC with cheesecloth) Subsequently the gauze was removed,placed in a stomacher bag and squeezed from the outside to release a maximum volume of 25-35 mL. Retained water was passed through a Millipore ® filter. The filters were placed in TSA+AMP plates andincubated 24h/37ºC. For two lowest spiking levels, 100 µL will be transferred to 5 mL TSB+AMP incubated and tested via Reveal® Salmonella Spp or E. coli O157:H7 lateral flow device. For E. coliinoculum levels 10¹ and 10 ³ had the same behavior where MMS were positive. For the inoculum10² two the samples positive for both MMS TFF. All samples were positive for MMS and TFF for the inoculum 104....
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