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J Food Prot. 2017 Oct;80(10):1768-1776. doi: 10.4315/0362-028X.JFP-16-529.

Development of a Novel Listeria Enrichment Broth for the Isolation of Pathogenic Listeria.

Author information

1
State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Chinese Center for Disease Control and Prevention, Changping, Changbai Road 155, Beijing 102206, People's Republic of China.

Abstract

Listeriosis, the disease caused by pathogenic Listeria species, can present severe symptoms in susceptible people. The goal of this study was to develop a novel enrichment broth, Listeria allose enrichment broth (LAEB), to improve isolation of Listeria monocytogenes and Listeria ivanovii from samples through incorporating a specific carbohydrate and reducing inhibitor concentrations. Other coexisting bacteria, particularly Listeria innocua, can interfere with the isolation of pathogenic Listeria in such ways as overgrowth of L. innocua and the generation of inhibitory metabolites. The incorporation of allose into the novel LAEB was effective for slowing the growth of L. innocua and other nontarget microorganisms. We determined that 35°C and pH 7.0 under aerobic conditions are optimal for Listeria growth in this medium. The novelty of the use of LAEB is the single enrichment procedure at 35°C for 24 h, obviating the need for a secondary enrichment medium. In 50 simulated samples, the sensitivity of the LAEB method (86%) was higher than that of the International Organization for Standardization (EN ISO) method (70%). In 142 naturally contaminated samples tested, the isolation rate for pathogenic Listeria with the LAEB method was 26.0% (37 of 142 samples), which was significantly higher than the 17.6% (25 of 142 samples) for the EN ISO method. Higher isolation rates and a quicker and easier protocol make the novel LAEB method an appropriate alternative for the isolation of pathogenic Listeria.

KEYWORDS:

Allose; Enrichment broth; Listeriosis; Pathogenic Listeria

PMID:
28945113
DOI:
10.4315/0362-028X.JFP-16-529
[Indexed for MEDLINE]

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