Rapid and simple biochemical detection for Salmonella spp. using modified LB broth and the MUCAP test

Keum-Il Jang, Jun-Bae Ahn, Kwang-Yup Kim

                                                                                  

Abstract

In this study, we developed a rapid Salmonella detection system and confirmed its detection efficiency using modified selective pre-enrichment and the 4-methyl umbelliferyl caprilate (MUCAP) test. Luria-Bertani (LB) medium without auto-fluorescence was modified by the addition of a bile salt mixture and sodium citrate as inhibitors, after which ferrous sulfate and sodium thiosulfate were added for the induction of H₂S gas. In a mixed culture of Staphylococcus aureus, Escherichia coli, and Salmonella enteritidis in Salmonella detective modified LB (SDMLB) medium, S. enteritidisdominated regardless of their initial population size. Among 10 bacterial strains, Salmonella andEnterobacter spp. were cultured and distinguished by the H₂S test because the Enterobacter spp. was unable to produce H₂S gas in SDMLB medium. MUCAP testing produced blue fluorescence only for Salmonella spp. Tests for Salmonella using chicken skin and egg shells revealed the presence of Salmonella spp. Thus, foods carrying Salmonellae were detected rapidly and simply using this method.

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Keywords : Salmonella ,H2S test ,4-methyl umbelliferyl caprilate (MUCAP) test ,Salmonella detective modified LB (SDMLB) medium ,rapid detection.