| Autor: |
Kanuganti, Sreenivas R., Wesley, Irene V., Reddy, P.Gopal, Mckean, James, Hurd, H.Scott |
| Zdroj: |
Journal of Food Protection; September 2002, Vol. 65 Issue: 9 p1470-1474, 5p |
| Abstrakt: |
In this study, we surveyed hogs (n= 300) as well as pork products (ground pork and raw chitterlings) for Listeria monocytogenes. Pig specimens collected before (tonsil swabs) and after slaughter (tonsils, lymph nodes, carcass swabs, and rectal contents) were examined for L. monocytogenesby enrichment with conventional enrichment broths followed by subculturing to selective agar. A multiplex polymerase chain reaction assay targeting the highly conserved 16S rRNA gene of the Listeriaspecies as well as the hlyAgene unique to L. monocytogeneswas used to screen aliquots of the enrichment (method I) as well as to confirm presumptive Listeriacolonies from Columbia agar with 0.05% glucose supplemented with polymyxin B-acriflavine-lithium chloride-ceftazidime-aesculin-mannitol (PALCAM; method II). Subculturing to PALCAM agar was the more sensitive of the two methods on the basis of the overall detection of Listeria. For hog tissues, method I detected L. monocytogenes(0.87% positive) and no other Listeriaspp. in all samples (n= 1,849). In contrast, method II detected significantly more (P< 0.05) L. monocytogenes(2.38%) and Listeriaspp. (0.38%) in these tissues. For small intestines (n= 300 raw chitterlings), L. monocytogeneswas identified in 8.3% of enrichments with University of Vermont modified Listeriaenrichment broth; plating to PALCAM slightly improved recovery (9%). Overall, ground pork samples (n= 340) harbored L. monocytogenes(45% positive) and other Listeriaspecies (1.5% positive), as determined by method I. Subculturing to PALCAM significantly (P< 0.05) improved the detection of L. monocytogenes(50.2%) but not that of other Listeriaspecies (1.7%). L. monocytogenesisolates (n= 243) were assigned to serotype 1 (53.5%), serotype 4 (25%), and serotypes other than 1 and 4 (21.4%). |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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