Presence of Listeria spp. and Listeria monocytogenes in Environments and Products in a Plant Processing Chicken Meat

Introduction: The presence of L. monocytogenes in products ready to eat must be well controlled. This control must be based on the environmental and in products bacterium detection. Listeria spp results as an alert indicator to minimize the risk of L. monocytogenes.

Purpose: The aim of this study was to assess the presence of Listeria spp and L. monocytogenes in environments and products coming from areas of low risk (LR) and high risk (HR) of a plant producing poultry meat ready to eat.

Methods: In the areas of the LR and HR environments, 26 and 411 samples, respectively, were collected with a sponge. In products 55 samples were collected before cooking (LR) as well as 62 samples after cooking (HR). All samples were analyzed by VIDAS®  LDUO (bioMérieux). The colonies of Listeria were identified by the VITEK 2^TMsystem (bioMérieux).

Results: In LR environment L. innocua and L. monocytogenes were isolated in 19.3% and 69.2% of the samples, respectively. In HR, L. innocua was isolated in 3.6% of samples analyzed, L. welshimeri 0.5% and L. monocytogenes in 1.9%. In products before cooking, L. innocua was found in 14.5%, L. welshimeri 3.6%   and L. monocytogenes in 76.3%. After cooking, L. innocua was isolated in 1.6% of product samples and L. monocytogenes in 4.8%. L. welshimeri was not found in the products.

Significance: Proper cooking allowed the control of Listeria spp as well as in processed chicken meat products, but there is a risk of contamination of the product after this step, possibly due to contact with contaminated surfaces. Control of Listeria spp and L. monocytogenes must be a set of actions of production practices and environmental control and in the end product.