Detection of Listeria monocytogenes in Ready-to-Eat Meat Products
Asma M.M.A. Abdelgadir, Kunwar K. Srivastava and P. Gopal Reddy
DOI : 10.3844/ajavsp.2009.101.107
American Journal of Animal and Veterinary Sciences
Volume 4, Issue 4
Problem statement: The objective of this study was to develop a rapid and sensitive method for the detection of Listeria monocytogenes and to screen large number of ready-to-eat (RTE) meat samples. Approach: A total of 250 fresh RTE meat samples of different varieties (chicken, turkey, beef, pork and cold cuts) were purchased from local grocery stores. Results: From the 250 total samples, 50 samples were randomly selected and subjected to DNA extraction, and immunomagnetic Separation (IMS) followed by RT-PCR analysis using primers against L. monocytogenes specific gene (hlyA). Five RTE samples negative by culture and by RT-PCR were spiked with L. monocytogenes (ATCC-19111) and used as positive controls. While all positive samples were detected as positive, all 50 samples were negative with both methods i.e., IMS followed by hlyA gene-based RT-PCR assay and the standard culture methods. Following this, all the 250 samples were tested by standard culture method as well as the IMS+RT-PCR assay. Five samples (2.0%) were presumptively diagnosed as positive for Listeria on Oxford agar. All the five confirmed to be positive for L. monocytogenes by IMS+RT-PCR assay. Conclusion/Recommendations: The IMS + RT-PCR procedure was considerably more rapid and required only 28 h compared to 96-120 h for the conventional culture method. This method would be useful as the criteria for addressing the costly meat recalls and reducing outbreaks.
© 2009 Asma M.M.A. Abdelgadir, Kunwar K. Srivastava and P. Gopal Reddy. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.