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United States Department of Agriculture

Agricultural Research Service

Research Project: PATHOGEN PERSISTENCE AND PROCESSING OPTIMIZATION FOR ELIMINATION IN FOODS

Location: Food Safety and Intervention Technologies

Title: Prevalence, levels, and relatedness of Listeria monocytogenes isolated from raw and ready-to-eat foods at retail markets in Culiacan, Sinaloa, Mexico

Authors
item Castaneda-Ruelas, Marisol -
item Castro-Del Campo, Nohelia -
item Felix, Josefina Leon -
item Valdez Torres, Jose Benigno -
item Guzman-Uriarte, Roberto -
item Luchansky, John
item Porto Fett, Anna
item Shoyer, Brad
item Chaidez-Quiroz, Cristobal -

Submitted to: Journal of Microbiology Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 28, 2013
Publication Date: March 28, 2013
Citation: Castaneda-Ruelas, M., Castro-Del Campo, N., Felix, J., Valdez Torres, J., Guzman-Uriarte, R., Luchansky, J.B., Porto Fett, A.C., Shoyer, B.A., Chaidez-Quiroz, C. 2013. Prevalence, levels, and relatedness of Listeria monocytogenes isolated from raw and ready-to-eat foods at retail markets in Culiacan, Sinaloa, Mexico. Journal of Microbiology Research. 3(2):92-98.

Interpretive Summary: Listeria monocytogenes (LM) is an important foodborne pathogen due to its widespread occurrence and the severity of listeriosis. Ready-to-eat (RTE), meat, poultry, vegetables, and dairy products are vehicles for listeriosis transmission. Confirmation of the relatively high occurrence and levels of Listeria monocytogenes on higher volume, higher risk foods at retail markets suggests that efforts should be directed to better educate store personnel and consumers of the risk of listeriosis and the benefits of using proper storage and preparation methods to reduce their risk of illness. Molecular typing of L. monocytogenes recovered from foods and food contact surfaces at retail markets can establish relatedness among strains and identify sources that harbor the pathogen which, in turn, can lessen the likelihood and/or severity of foodborne listeriosis.

Technical Abstract: The prevalence, levels, and relatedness of Listeria monocytogenes (LM) strains isolated from select raw and ready-to-eat (RTE) foods at retail markets in Culiacan, Sinaloa, Mexico were determined during 2011. LM was isolated from 26 (14.4%) of 180 food samples. Raw chicken breast showed the highest occurrence (23.3%; 14/60), followed by RTE turkey frankfurters (11.7%; 7/60) and then raw ground beef (8.3%; 5/60). Pathogen levels ranged from 0.23 to 110 MPNg-1. One isolate from each of the 26 positive samples was serotyped as follows: 1/2a (9 isolates), 1/2b (4 isolates), 1/2c (2 isolates), 3b (1 isolate), and 4b (10 isolates). Twenty-three of the 26 strains were resistant to a least one of 18 antibiotics tested and were delineated into 11 antibiotic profiles. The 26 isolates were further delineated into 14 AscI pulsotypes. These data confirm a relatively high prevalence and levels of LM on food purchased at retail markets in Sinaloa, most likely originating from various sources due to the low relatedness among isolates recovered from positive samples. Further studies are warranted to identify harborage points and to develop interventions to lower the prevalence of LM and reduce the risk of listeriosis from food for purchase at retail markets in Culiacan.

Last Modified: 8/30/2014