Comparative studies of nucleic acid hybridization assay for Listeria in foods.
A nucleic acid hybridization assay has been developed for Listeria spp. in dairy foods and environmental samples. The assay is based on detection of unique Listeria 16S rRNA sequences by using a 32P-labeled synthetic DNA probe. Inclusivity and exclusivity of the probe were confirmed with 139 Listeria isolates representing all known species, and 73 non-Listeria bacterial strains. In this paper, we present results from our preliminary studies comparing the hybridization assay with conventional culture on a total of 575 specimens that represent a variety of inoculated and uninoculated foods and environmental samples. The assay, which is done in a filter manifold format after 2 days of cultural enrichment, requires a total assay time of less than 2.5 days. The false-negative rate for all sample groups tested using the GENE-TRAK hybridization assay was less than the rate for culture. Thus, the new assay allows rapid screening of the indicated product groups and provides reliable numerical results.
Klinger
J D
JD
GENE-TRAK Systems, Framingham, MA 01701.
Johnson
A
A
Croan
D
D
Flynn
P
P
Whippie
K
K
Kimball
M
M
Lawrie
J
J
Curiale
M
M
D003611:Dairy Products; D005516:Food Microbiology; D008087:Listeria / Q000032:analysis*; D009693:Nucleic Acid Hybridization; D012329:RNA, Bacterial / Q000032:analysis*; D014481:United States; D014486:United States Food and Drug Administration
D012329:RNA, Bacterial