Serotypes and Pulsotypes Diversity of Listeria monocytogenes in a Beef-Processing Environment

Abstract

Utensils and equipment from meat-processing facilities are considered relevant cross-contamination points of Listeria monocytogenes to foods, demanding tracking studies to identify their specific origins, and predict proper control. The present study aimed to detect L. monocytogenes in a beef-processing facility, investigating the diversity of serotypes and pulsotypes in order to identify the possible contamination routes. Surface samples from knives (n=26), tables (n=78), and employees hands (n=74) were collected before and during the procedures from a beef-processing facility, in addition to surface samples of end cuts: round (n=32), loin (n=30), and chuck (n=32). All samples were subjected to L. monocytogenes screening according ISO 11.290-1, and the obtained isolates were subjected to serotyping and pulsed-field gel electrophoresis. Listeria spp. were identified in all processing steps, in 61 samples, and L. monocytogenes was detected in 17 samples, not being found only in knives. Eighty-five isolates were identified as L. monocytogenes, from serotypes 1/2c (n=65), 4b (n=13), and 1/2b (n=7), being grouped in 19 pulsotypes. Considering these results, cross-contamination among hands, tables, and beef cuts could be identified. The obtained data indicated the relevance of cross-contamination in the beef-processing facility, and the occurrence of serotypes 1/2b and 4b in beef cuts distributed for retail sale is a public health concern.

In-Depth Longitudinal Study of Listeria monocytogenes ST9 Isolates from the Meat Processing Industry: Resolving Diversity and Transmission Patterns Using Whole-Genome Sequencing

“…One clear indication that raw meat is a common source of the introduction of L. monocytogenes into more than one factory was the observation that subcluster B2 isolates, mainly found in the raw meat department used for cutting and marinating raw beef in factory M4, also were found on the raw side, but not in the high-risk zone, of factory M1. L. monocytogenes strains, including ST9 strains, have frequently been found to persist in meat slaughterhouses ( 5 , 6 , 15 , 50 – 56 ). Therefore, a common primary source of a certain L. monocytogenes strain present in more than one meat processing plant potentially could be one that persists in a slaughterhouse supplying raw meat to multiple processing plants.…”

Application of Whole Genome Sequencing to Aid in Deciphering the Persistence Potential of Listeria monocytogenes in Food Production Environments

“…Listeriosis in humans is mostly associated with the consumption of contaminated food. Many studies reported that the contamination of food-processing facilities and associated environments is often the route by which foods become contaminated [ 23 , 24 , 25 , 26 , 27 , 28 ].…”

Detection and Virulence Characterization of Listeria monocytogenes Strains in Ready-to-Eat Products

“…The presence of virulence genes in L. monocytogenes isolates obtained from food and food processing facilities has already been described in a number of studies, demonstrating their relevance for the characterization of this pathogen's virulence potential (Lomonaco et al, 2012;Jamali et al, 2013;Camargo et al, 2015;Haubert et al, 2015;Silva et al, 2016). A large number of genes potentially involved in virulence have been recognized by Maury et al (2016).…”