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Title: Listeria monocytogenes from slaughter plant to fully cooked product – sources, sites and potential for intervention

item Berrang, Mark

Submitted to: International Poultry Scientific Forum
Publication Type: Abstract Only
Publication Acceptance Date: 12/15/2012
Publication Date: 1/28/2013
Citation: Berrang, M.E. 2013. Listeria monocytogenes from slaughter plant to fully cooked product – sources, sites and potential for intervention. International Poultry Scientific Forum. P.18.

Interpretive Summary:

Technical Abstract: Listeria monocytogenes is a human pathogen that has been associated with fully cooked poultry products. This organism is not highly prevalent on live broilers; prevalence tends to increase as carcasses proceed through an initial processing plant. In one study we found no L. monocytogenes on pre-scald carcasses, but when we examined deboned thighs from the same flock 4% were positive. Even a low percentage of positive cut up chicken parts translates to a substantial number when one considers the vast numbers of parts moved from a slaughter plant to a large commercial cooking operation. We have documented raw poultry meat as the most important source of L. monocytogenes to commercial cooking facilities. Once a cooking plant has been exposed, some subtypes of L. monocytogenes can colonize the plant and become long term residents in floor drains. Floor drain contamination is a concern because we have found that Listeria can become airborne when a hose is sprayed into a drain during wash down. Aerosolized Listeria can result in the contamination of product in either a slaughter plant prior to shipment or ready-to-eat product that has been fully cooked. Therefore, interventions are needed to control L. monocytogenes before it can be transferred from a slaughter plant to a cooking plant on raw product. In studies involving floor drains, we found that sanitizers, especially peroxide based chemicals, can effectively lower the numbers of L. monocytogenes both in floor drain liquid and attached to the inner surfaces of the drain pipe as a biofilm. In some cases adding a physical disruption such as ultra-sound may help to breakup biofilm architecture making chemical treatment more effective. Another approach is to lower numbers of L. monocytogenes on cut up broiler parts prior to packing for transport to a cooking plant. We have found that germicidal ultra-violet light shows promise as a means to significantly lower numbers of Listeria on raw product. Currently, work is being conducted to further optimize potential interventions and better understand the microbial ecology of human pathogens in poultry processing environments.