Purpose: Objectives of this study were an estimation of Listeria monocytogenes prevalence in poultry carcasses at broiler abattoirs and their molecular characterization by Multiplex-PCR and the PFGE method.
Methods: Prevalence of Listeria contamination in three industrial poultry abattoirs was investigated by sampling carcasses at the end of processing, after packaging and refrigerating. A total of 212 carcasses were collected: 52 from abattoir A and 80 from both abattoir B and C. Listeria screening was performed according to ISO 11290-1 method.
Results: 46.7% of samples presented Listeria: L. monocytogenes (8.9%), L. innocua (32.5%), L. grayi (4.7%) and L. welshimeri (0.5%). The Listeria monocytogenes contamination rate varied from 5 to 11.5 %, between the three abattoirs. Listeria innocua was the most commonly identified species: 8.8% in abattoir A, 33.7% in both abattoirs B and C. 26 isolates were subjected to characterization by serogrouping by Multiplex –PCR. L. monocytogenes serogroups were IIa , IIb and IVb. IIa was common to all abattoirs; IIb and IVb were reported only in abattoir C. The serotypes (1/2a, 1/2b, and 4b) cause the vast majority of clinical cases. Serotype 1/2a is the most frequently isolated from food, serotype 4b causes the majority of human epidemics.
Significance: The study demonstrated the high prevalence of Listeria spp. and specifically L. monocytogenes in raw broiler, this high incidence is a problem that should be of concern to the food producers. Sanitation programs to prevent or at least to reduce Listeria contamination should be adopted.