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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Food Safety and Enteric Pathogens Research » Research » Publications at this Location » Publication #104813
Title: RAPID DETECTION OF LISTERIA MONOCYTOGENES IN FOOD AND FOOD ANIMALS

Author
item KANUGANTI, SREENIVAS - TUSKEGEE UNIV., ALABAMA
item Wesley, Irene
item Hurd, Howard
item KARRIKER, L. - IA STATE UNIV., AMES, IA
item MCKEAN, J - IA STATE UNIV., AMES, IA
item BOYAPALLE, S - TUSKEGEE UNIV., ALABAMA
item REDDY, P - TUSKEGEE UNIV., ALABAMA

Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 11/9/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The objective of this study was to streamline the detection and identification of Listeria monocytogenes (LM) in livestock and foods. Hog tonsil scrapings, hog tissues collected at necropsy, ground pork and turkey washes were inoculated into UVM I (10% w/v) and after incubation (3 days) transferred to UVM 2. After 2 days, samples were plated to Palcam magar. Characteristic LM colonies were verified using the multiplex PCR assay, which targets the 16S rRNA gene of Listeria and the hlyA gene unique to the species monocytogenes. To determine when LM achieved detectable levels during enrichment, template DNA was extracted directly from UVM 1, 2, Palcam agar and screened by the multiplex PCR and the immunfluorescent (VIDAS LMO) assays. When screened directly from UVM 2 by VIDAS LMO and PCR, overall 30%(15 of 50) of ground pork samples and 16%(4 of 25) of turkey washes were positive for LM. In contrast, multiplex PCR screening of colonies from Palcam agar showed 24% (12 of 50) of ground pork and 8% (2 of 25) of turkey washes were positive. This indicates that screening of UVM 2 enrichment may be a better indicator of LM prevalence than subculture to Palcam. LM positive isolates (n=33) of ground pork were serotyped and assigned to type 4 (72%) and type 1 (14%). 14% of isolates were neither serotype 1 nor 4. For live hogs, out of 150 samples each of carcasses tonsils and ileocecal lymph nodes tested, LM was detected once from tonsils and nodes by multiplex PCR. In contrast LM was found in 30% of ground pork produced that same day from the packing plant.