Submitted to: Poultry Science
Publication Type: Abstract Only
Publication Acceptance Date: May 11, 2000
Publication Date: August 18, 2000
Citation: HINTON JR, A., DICKENS, J.A. ABILITY OF FORMULATIONS OF THE COMMERCIAL HERBAL EXTRACT, PROTECTA, TO INHIBIT LISTERIA MONOCYTOGENES GROWTH IN VITRO. POULTRY SCIENCE. 2000.
The ability of 4 formulations of Protecta to inhibit the growth of Listeria monocytogenes was determined. Solutions of Protectas 1, 2, 3a, or 3b were prepared by dissolving the extracts in distilled water. The Protecta solutions were filter sterilized and added to sterile Brain Heart Infusion (BHI) to produce concentrations of 0, 0.005, 0.010, 0.015, or 0.020% (w/v) of each Protecta in the medium. L. monocytogenes cultures were diluted and added to BHI-Protecta mixtures to yield a final concentration of 103 cfu of L. monocytogenes/ml. Aliquots of the inoculated BHI-Protecta mixtures were added to a Bioscreen honeycomb plate. The filled honeycomb plates were placed in a Bioscreen C Microbiology Reader, and the OD of the cultures were monitored during a 48 h incubation period at 37C. Analysis of results indicated that during the incubation period, there was a significant increase in the OD of L. monocytogenes cultures grown in BHI not supplemented with Protecta and in BHI supplemented with 0.005% of Protectas 1, 2, 3a, or 3b; 0.010% of Protectas 2, 3a, or 3b; or 0.015% of Protecta 3b. There was no significant change in the OD of cultures grown in BHI supplemented with concentrations >0.010% of Protecta 1, >0.015% of Protectas 2 or 3a, or 0.020% of Protecta 3b after 48 h. Findings of this study indicate that appropriate concentrations of each Protecta formulation can inhibit L. monocytogenes growth in vitro. The relationship between the inhibitory activities of the Protectas can be expressed as: Protecta 1>Protecta 2 and 3a>Protecta 3b.