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Updated: Jan 25, 2026
Listeria monocytogenes Infection of the Brain
Published on: October 2, 2018
Comparisons of Selected Methods with the Fung-Yu Tube Procedure for Determining Listeria monocytogenes and Other
Linda S L Yu1, Daniel Y C Fung1
1Department of Animal Sciences and Industry, Kansas State University, Manhattan, Kansas 66506-0201.
Abstract:
The ability of the motility enrichment Fung-Yu tube procedure with Oxyrase™ enzyme to detect the presence of Listeria monocytogenes inoculated into ground beef samples was compared to the USDA-FSIS method. Three strains of L. monocytogenes (LM 101M, LM 103M, and Scott A) were inoculated separately into sterilized ground beef or culture broth. The inoculum levels used were as low as 1 to 1000 Listeria cells per g of meat or per ml of broth. The Fung-Yu tube procedure produced results as sensitive as the USDA procedures and provided a shorter detection time of 26-48 h. A total of 215 retail-level meat and poultry products were analyzed comparatively by the Fung-Yu tube and the GENETRAK® DNA hybridization methods for Listeria detection. Six Listeria spp. ( L. denitrificans , L. grayi , L. innocua , L. ivanovii , L. monocytogenes , and L. murrayi ) were identified among the isolates. All 48 presumptively positive samples determined by the Fung-Yu tube method were further confirmed to harbor Listeria by biochemical tests. Eleven samples were missed by the GENETRAK® procedure, probably because of the enrichment procedure. L. monocytogenes was isolated from ground beef, pork sausage, smokie links, and cheese hot dogs. Among cooked samples examined, only cheese hot dogs and macaroni and cheese loaf showed substantial incidence of Listeria contamination.
Insights
The Fung-Yu tube method offers sensitive Listeria monocytogenes detection in ground beef, comparable to USDA methods but with faster results. This motility enrichment technique is effective for food safety analysis.
Area of Science:
- Food Microbiology
- Food Safety
- Bacteriology
Background:
- Listeria monocytogenes is a significant foodborne pathogen.
- Accurate and rapid detection methods are crucial for food safety.
- Existing methods for Listeria detection can be time-consuming.
Purpose of the Study:
- To evaluate the efficacy of the motility enrichment Fung-Yu tube procedure for Listeria monocytogenes detection.
- To compare the Fung-Yu tube method with the USDA-FSIS method and GENETRAK® DNA hybridization.
- To assess the detection time and sensitivity of the Fung-Yu tube procedure.
Main Methods:
- Inoculation of ground beef and broth with Listeria monocytogenes strains at low levels.
- Comparison of Fung-Yu tube procedure with USDA-FSIS method.
- Comparative analysis of Fung-Yu tube and GENETRAK® DNA hybridization on retail meat and poultry products.
- Biochemical confirmation of presumptive positive samples.
Main Results:
- The Fung-Yu tube procedure demonstrated sensitivity comparable to USDA methods.
- Detection time using the Fung-Yu tube was significantly shorter (26-48 h).
- The Fung-Yu tube method identified Listeria in ground beef, pork sausage, smokie links, and cheese hot dogs; GENETRAK® missed 11 samples.
Conclusions:
- The Fung-Yu tube procedure is a sensitive and rapid method for detecting Listeria monocytogenes in food samples.
- This method offers advantages in terms of speed and potentially broader detection compared to DNA hybridization techniques.
- Listeria contamination was found in various retail meat and poultry products, highlighting the need for effective detection strategies.
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