Journal of Food and Nutrition Research
ISSN (Print): 2333-1119 ISSN (Online): 2333-1240 Website: http://www.sciepub.com/journal/jfnr Editor-in-chief: Prabhat Kumar Mandal
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Journal of Food and Nutrition Research. 2017, 5(11), 832-837
DOI: 10.12691/jfnr-5-11-6
Open AccessArticle

Detection and Quantification of Listeria monocytogenes in Ready-to-eat Vegetables, Frozen Vegetables and Sprouts Examined by Culture Methods and Real-time PCR

Monika Moravkova1, , Veronika Verbikova1, Veronika Michna1, Vladimir Babak1, Hana Cahlikova2, Renata Karpiskova2 and Petr Kralik1

1Department of Food and Feed Safety, Veterinary Research Institute, Hudcova 70, 621 00 Brno, Czech Republic

2Department of Bacteriology, Veterinary Research Institute, Hudcova 70, 621 00 Brno, Czech Republic

Pub. Date: November 03, 2017

Cite this paper:
Monika Moravkova, Veronika Verbikova, Veronika Michna, Vladimir Babak, Hana Cahlikova, Renata Karpiskova and Petr Kralik. Detection and Quantification of Listeria monocytogenes in Ready-to-eat Vegetables, Frozen Vegetables and Sprouts Examined by Culture Methods and Real-time PCR. Journal of Food and Nutrition Research. 2017; 5(11):832-837. doi: 10.12691/jfnr-5-11-6

Abstract

In this study, a total of 175 samples of ready-to-eat vegetables, frozen vegetables and sprouted seeds originating in 10 states of the European Union and from 32 manufacturers were collected during a period of one year and examined for the presence of Listeria monocytogenes using standard culture methods and qPCR. In addition to these methods, isolation of Listeria monocytogenes was also carried out following a unified sample preparation for combined downstream use in culture and qPCR analysis. Standard culture and culture preceded by unified sample preparation, showed that L. monocytogenes was present in 6.9% and 11.4% of analyzed samples, respectively, in low numbers. Application of qPCR revealed only 2.3% of samples to be positive for L. monocytogenes in small quantities (less than 10 cells/gram). A statistically significant higher occurrence of L. monocytogenes was seen in frozen vegetables compared to ready to eat vegetables (p<0.01; Fisher’s exact post-hoc tests with Bonferroni’s correction) or sprouts (p<0.05; Fisher’s exact post-hoc tests with Bonferroni’s correction). Therefore, temperature abuse in food containing pieces of frozen vegetables without any processing such as cooking, may pose health risks, especially for sensitive individuals such as pregnant women, children, the elderly, and immunocompromised individuals.

Keywords:
Listeria monocytogenes Foodborne pathogens Molecular methods qPCR Ready-to-eat

Creative CommonsThis work is licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

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