Incidence and Persistence of in the Catfish Processing Environment and Fresh Fillets

Abstract

Incidence of Listeria spp. in whole raw catfish, catfish fillets, and processing environments from two catfish processing facilities was determined in August 2008 and August 2009. Thirty-nine (18.4%) of 212 samples collected in August 2008 were positive for Listeria monocytogenes. Prevalences of Listeria species L. innocua and L. seeligeri-L. welshimeri-L. ivanovii were 11.3 and 23.6%, respectively. Of 209 samples collected in August 2009, 12.4% were positive for L. monocytogenes, 11% for L. innocua, and 19.6% for L. seeligeri-L. welshimeri-L. ivanovii. No Listeria grayi was detected in any of the samples. L. monocytogenes was not found in catfish skins and intestines, but was detected in catfish fillets, on food contact surfaces, and on non-food contact surfaces with frequencies of 45.0, 12.0, and 11.1%, respectively. In August 2008 isolates, serotypes 1/2b (62.2%) and 3b (15.6%) were frequently isolated, whereas the majority of the August 2009 isolates (92.3%) were serotype 1/2b. Genotyping analyses revealed that some genotypes of L. monocytogenes isolates were detected in one facility even after a year, but no persistence of L. monocytogenes was observed in the other facility. In addition, some L. monocytogenes isolates from fresh fillets showed genotypes that were either identical, or more than 90% similar, to those of L. monocytogenes isolates from food contact surfaces in the processing lines. The results of this study suggest that processing environment rather than whole raw catfish is an important source of L. monocytogenes contamination in the catfish fillets. These results should assist the catfish industry to develop better control and prevention strategies for L. monocytogenes.

Incidence of Listeria monocytogenes and Listeria spp. in a Small-Scale Mushroom Production Facility

“…Alternatively, it has been proposed that L. innocua may inhibit L. monocytogenes growth by producing bacteriocins or through a straindependent quorum-sensing mechanism (9, 21). However, approximately equal proportions of the two species were found in separate fish processing plants by Eklund et al (27) and Chen et al (15). Conversely, Hu et al (34) did not recover any L. innocua from 782 environmental and product samples taken from a cold-smoked fish processing facility.…”

“…are capable of existing as saprophytes in soil and decaying vegetation and are ubiquitous in agricultural environments including water, sewage, silage, and animal feces (57). Taxonomically, the genus is composed of six species that can be found in agricultural and food processing environments: L. monocytogenes, L. ivanovii, L. seeligeri, L. innocua, L. welshimeri, and L. grayi (15). L. monocytogenes is a facultative intracellular pathogen of humans and animals and is readily found in damp, cool indoor environments such as produce packing houses (49).…”

The Role of Stress and Stress Adaptations in Determining the Fate of the Bacterial Pathogen Listeria monocytogenes in the Food Chain

“…Different studies have been conducted to investigate the main sources of contamination within food processing facilities (Johansson et al, 1999; Hansen et al, 2006; Leite et al, 2006; Ho et al, 2007; Chen et al, 2010a; Rivoal et al, 2010). Hansen et al (2006) found that there was evidence of strains isolated from the outside environment also being identified within fish slaughterhouses.…”

“…Hansen et al (2006) found that there was evidence of strains isolated from the outside environment also being identified within fish slaughterhouses. Other studies have shown that operators within a facility or different pieces of equipment may also be considered sources of contamination (Leite et al, 2006; Lomonaco et al, 2009; Chen et al, 2010a). Lomonaco et al (2009) isolated L. monocytogenes from locker rooms, hallways and toilets within a gorgonzola producing facility suggesting the possibility that personnel within the factory contributed to the problem of contamination.…”

Evaluation of Methods To Assess the Biofilm-Forming Ability of Listeria monocytogenes

“…Outbreaks are often associated with consumption of ready-to-eat foods produced in industrial facilities. The contamination of these foods is associated with colonization of industrial environments, which can remain contaminated for long periods of time (2,8,18).…”