Efficacy of Pecan Shell Extracted Organic Antimicrobials Inhibiting the Growth of Listeria spp. and Listeria monocytogenes Strains Adhered on Chicken Skin

Introduction: Growers and processors of Certified Organic foods are in need of suitable organic antimicrobials. This study addresses utilization of organic antimicrobials against food pathogens that are increasingly exhibiting resistance to conventional antimicrobials and presents the efficacy of the tested natural antimicrobials in organic food system of poultry meat products. 

Purpose: The purpose of our current research was to develop and test effective chemical-free natural antimicrobials derived from an all-natural byproduct, organic pecan shells.

Methods: Unroasted and roasted organic pecan shells were subjected to solvent free extraction of antimicrobials that were tested against Listeria spp. and L. monocytogenes serotypes to determine the minimum inhibitory concentrations (MIC) of antimicrobials. The effectiveness of pecan shell extracts were further tested using a poultry skin model system and the growth inhibition of the Listeria cells adhered onto the skin model were quantified. 

Results: In addition to inhibiting the native bacteria on the skin, the solvent free extracts of pecan shells inhibited Listeria strains at MICs of 0.38%. The antimicrobial effectiveness tests on poultry skin model exhibited nearly a 2-log reduction of the inoculated cocktail mix of Listeria strains when extracts of pecan shell powder were used. The extracts produced higher than 4-log reduction of the native spoilage bacteria on the chicken skin.

Significance: The pecan shell extracts may prove to be very effective alternative antimicrobials against food pathogens and supplement the demand for effective natural antimicrobials for use in organic meat processing.