In this study, we developed a rapid, reliable, sensitive and
inexpensive single test tube multiplex PCR assay for the simul-
taneous detection of multicopy ipaH and single-copy mxiC and
virB virulence genes. The assay can detect Shigella or EIEC cells in
the indigenous microflora of different types of produce, post-
enrichment. Because the boiling procedure currently recom-
mended to prepare tested DNAs may not efficiently remove
matrix-associated PCR inhibitors, we also evaluated three com-
mercial DNA extraction kits by determining the lowest number
of Shigella cells they could identify in the enrichment broth
against the bacterial background microflora from the surface of
tomatoes, sweet peppers, cilantro, parsley, cucumbers and green
onions.