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United States Department of Agriculture

Agricultural Research Service

Title: Evidence of effective penetration of Listeria monocytogenes biofilms by disinfectant

item Arnold, Judy
item Kramer, S
item Zambelli-warner, A

Submitted to: International Food Technology Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2009
Publication Date: 6/8/2009
Citation: Arnold, J.W., Kramer, S., Zambelli-Warner, A. 2009. Evidence of effective penetration of Listeria monocytogenes biofilms by disinfectant. International Food Technology Meeting Abstracts. P.22.

Interpretive Summary:

Technical Abstract: The generation of protective biofilms by microorganisms that aggregate on food processing equipment surfaces is a major contributing factor to contamination and disinfection failure in meat and poultry processing facilities. Traditional disinfectants and cleaners do not effectively penetrate the biofilm matrix and are therefore unable to adequately control pathogens that are embedded within it. There is an urgent need for recognition of the importance of controlling biofilms, including the development and use of novel products that can effectively control Listeria monocytogenes biofilms in food processing environments. The purpose of this study is to establish efficacy against L. monocytogenes biofilm, as well as to compare efficacy against standard disinfectants and cleaners. Biofilms of Listeria monocytogenes (ATCC 19114) were grown on stainless steel coupons within a bioreactor under flow conditions, treated with test agent, stained with the biomass indicator crystal violet, and scraped off the coupons for biomass measurement. The stain 4', 6-Diamidino-2-phenylindole dihydrochloride was applied to the coupons to determine if biofilm remained, and the Live-Dead stain was applied to determine whether any remaining cells were viable. All samples were performed in triplicate, and the experiments were replicated. Percent removal was calculated as 1-[(ODtreated-ODblank)/(ODuntreated-ODblank)]. A threshold of 90% removal indicated good biofilm removal. At the recommended maintenance treatment with quarternary ammonium compound, 93% biofilm removal was achieved, as well as a 4-log reduction in total counts. At similar percentages of active ingredients, a quaternary ammonium compound alone achieved 78% biofilm removal at the maintenance level, hydrogen peroxide achieved 76% removal, and an alkaline detergent achieved 75% removal. The products have both antimicrobial and biofilm termination efficacy.

Last Modified: 06/28/2017
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