Characterization of Listeria monocytogenes isolated from a fresh mixed sausage processing line in Pelotas-RS by PFGE

Abstract

Listeria monocytogenes is a bacterium capable to adhere to the surfaces of equipment and utensils and subsequently form biofilms. It can to persist in the food processing environmental for extended periods of time being able to contaminate the final product. The aim of this study was to trace the contamination route of L. monocytogenes on a fresh mixed sausage processing line, from raw material to the final product. The isolates obtained were characterized by serotyping and molecular typing by pulsed-field gel electrophoresis (PFGE) using the restriction enzymes ApaI and AscI. L. monocytogenes was detected in 25% of the samples. The samples of raw material were not contaminated, however, the microorganism was detected in 21% of the environmental samples (food contact and non-food contact), 20.8% of the equipments, 20% of the food worker's hands, 40% of the mass ready to packaging and in all the final products samples, demonstrating that the contamination of final product occurred during the processing and the importance of cross contamination. PFGE yielded 22 pulsotypes wich formed 7 clusters, and serotyping yielded 3 serotypes and 1 serogroup, however, the presence of serotypes 4b and 1/2b in the final product is of great concern for public health. The tracing of contamination showed that some strains are adapted and persisted in the processing environment in this industry.

PFGE characterisation and adhesion ability of Listeria monocytogenes isolates obtained from bovine carcasses and beef processing facilities

“…Rivoal et al (2010) analysed 196 L. monocytogenes isolates from eggs and found that serotype 1/2a was the most prevalent, presenting 61.7% similarity by PFGE. In a study with L. monocytogenes isolates obtained from fresh sausage, several serotypes were identified (1/2b, 1/2c, 4b) with no evident association among the 22 identified PFGE profiles (von Laer et al, 2009). A similar PFGE profile diversity, independent of the identified serotypes, was observed in a retrospective study of L. monocytogenes isolates obtained from food and clinical samples (Nucera et al, 2010).…”

“…Considering the severity of symptoms and the high mortality rate (Allerberger & Wagner, 2010;Colodner et al, 2003;Jiang et al, 2008;Kerr, Dealler, & Lacey, 1988;Lamont et al, 2011;Warriner & Namvar, 2009), several studies were developed to identify the main sources of contamination and relevant foods associated with this pathogen and to characterise its virulence factors (Autio et al, 1999;Barbalho, Almeida, Almeida, & Hofer, 2005;Barros et al, 2007;Cordano & Rocourt, 2001;Gudbjornsdottir et al, 2004;Jiang et al, 2008;Lecuit, 2005;Linnan et al, 1988;Nucera et al, 2010;Peccio, Autio, Korkeala, Rosmini, & Trevisani, 2003;Thevenot, Dernburg, & Vernozy-Rozand, 2006;Vitas, Aguado, & Garcia-Jalon, 2004;von Laer et al, 2009;Warriner & Namvar, 2009).…”

“…monocytogenes is usually associated with dairy, meat and readyto-eat products (Autio et al, 1999;Cordano & Rocourt, 2001;Luber et al, 2011;Peccio et al, 2003;Rivoal et al, 2010;Vitas et al, 2004;von Laer et al, 2009) due to the utilisation of several types of equipment and utensils during processing and storage prior to refrigeration under conditions that favour contamination and growth (Gandhi & Chikindas, 2007). In addition, L. monocytogenes is relatively resistant to variations in pH and NaCl concentrations and several antimicrobial Meat Science 92 (2012) E-mail address: nero@ufv.br (L.A. Nero).…”

Highly specific fiber optic immunosensor coupled with immunomagnetic separation for detection of low levels of Listeria monocytogenes and L. ivanovii

“…In pregnant women, it causes premature births, miscarriages, and neonatal sepsis or fetal deaths. L. monocytogenes is ubiquitous and found in food-processing environments [2,3] and food products, including ethnic soft cheese [4,5], sliced lunch meats [6] and frankfurters, and seafood [7]. It has been implicated in numerous food outbreaks and recalls, including a large outbreak involving cantaloupe in the US, which caused 29 deaths and 1 miscarriage [8].…”

Molecular characterization of Listeria monocytogenes isolated from animal products in a city of Northern Brazil

“…This was confi rmed by VON LAER et al (2009) who analyzed samples of frescal sausage from a processing line in Pelotas, Brazil. These authors observed no contamination by L. monocytogenes in the raw material, but the pathogen was detected in all the fi nal product samples.…”