Inactivation of Salmonellae in liquid egg white by antimicrobial bottle coating with allvl isothiocyanate, nisin and ZnO nanoparticles

Authors: Jin, Zhonglin; Gurtler, Joshua

Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/10/2010
Publication Date: 12/10/2010
Citation: Jin, Z.T., Gurtler, J. 2010. Inactivation of Salmonellae in liquid egg white by antimicrobial bottle coating with allvl isothiocyanate, nisin and ZnO nanoparticles. Applied and Environmental Microbiology. 110(3):704-712.

Interpretive Summary: Salmonellosis is a leading cause of foodborne illness in the United States. In this study, an antimicrobial bottle coating method was developed to reduce the risk of outbreaks of human Salmonellosis caused by contaminated liquid eggs. Glass jars were coated with a mixture of polylactic acid (PLA) polymer and antimicrobial compounds and the efficacy of bottle coatings in inactivating Salmonella in liquid egg white was investigated. The PLA bottle coatings with antimicrobials effectively inactivated Salmonella in liquid egg albumen and the synergistic bactericidal effect was found when two or more antimicrobials were used together. This study demonstrated the commercial potential of applying the antimicrobial bottle coating method to liquid eggs, and possibly other fluid food products.

Technical Abstract: The purpose of this study was to develop an antimicrobial bottle coating effective at inhibiting the growth of Salmonella in liquid egg albumen (egg white) and reduce the risk of human Salmonellosis. Four-ounce glass jars were coated with a mixture of polylactic acid (PLA) polymer and antimicrobial compounds containing 100-500 µl allyl isothiocyanate (AIT), 250 mg nisin, 250 mg ZnO nanoparticles per jar, or their combinations. The coated jars contained 100 ml of liquid egg white (LEW) inoculated with a three-strain Salmonella enterica subsp. enterica cocktail at populations of 1000 CFU per ml or 10,000,000 CFU/ml, and stored at 10C for 28 days. The PLA coating with 500 mu AIT completely inactivated 3 and 7 log CFU per ml of Salmonella after 7 and 21 days of storage, respectively. A synergistic bactericidal effect against Salmonella occurred when two or more antimicrobials were used together. The PLA coating with 200 mu AIT in combination with 250 mg nisin reduced Salmonella populations to an undetectable level (<10 CFU/ml) after 21 days of storage, which was equivalent to the coating treatment with 500 µl AIT and more than a 5-log CFU/ml reduction. These data suggest that PLA coatings containing AIT alone or AIT in combination with nisin inactivated salmonellae in LEW.