title: Efficacy of egg cleaning compounds on eggshells contaminated with Salmonella enterica serovar Enteritidis.
abstract: Salmonella Enteritidis infections of egg contents can be related to external contamination of the shell. In this study, the efficacy of three commercial cleaning and/or sanitizing compounds (sodium carbonate, sodium hypochlorite, and potassium hydroxide) was evaluated for bactericidal activity at pH values of 10, 11, and 12 against various concentrations (10(2), 10(4), or 10(6) CFU/ml) of Salmonella Enteritidis inoculated onto the eggshell surface. Efficacy of these chemical agents was also assessed against Salmonella Enteritidis in aqueous suspension. Our results indicated that none of the chemicals applied at the recommended manufacturer's concentrations (sodium carbonate, 36 ppm; other treatments, 200 ppm) could eliminate Salmonella Enteritidis from eggshells artificially contaminated with the highest bacterial concentrations (10(4) or 10(6) CFU/ml). Higher concentrations of each product, at least 5 to 20 times greater than recommended doses, were needed to destroy the bacteria on egg surfaces. However, at or slightly above the manufacturer's recommended use concentrations, all three formulations were effective against Salmonella Enteritidis in aqueous suspension (10(8) CFU/ml) or on eggshells contaminated with 10(2) CFU/ml. For both shell and suspension assays, inactivation of Salmonella Enteritidis occurred at lower concentrations at pH 12 than at pH 11 and 10. Contact time between chemicals and Salmonella apparently influenced bacterial inactivation. Extended contact times (2 to 10 min) reduced minimum chemical concentrations necessary to inactivate the bacteria. However, neither pH nor contact time influenced Salmonella Enteritidis inactivation when the initial bacterial numbers on eggshells were high.
authors.affiliation: Department of Pathology and Microbiology, Faculty of Veterinary Medicine, Montreal University, 3200 Rue Sicotte Saint-Hyacinthe, Quebec, Canada J2S 2M2.
authors.forename: Gaudy
authors.initials: G
authors.lastname: Soljour
authors.forename: Mafu Akier
authors.initials: MA
authors.lastname: Assanta
authors.forename: Serge
authors.initials: S
authors.lastname: Messier
authors.forename: Martine
authors.initials: M
authors.lastname: Boulianne
mesh_terms: D000818:Animals; D002254:Carbonates / Q000494:pharmacology; D002645:Chickens; D015169:Colony Count, Microbial; D004202:Disinfectants / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004528:Egg Shell / Q000382:microbiology*; D005506:Food Contamination / Q000517:prevention & control; D005516:Food Microbiology; D006863:Hydrogen-Ion Concentration; D006878:Hydroxides / Q000494:pharmacology; D017680:Potassium Compounds / Q000494:pharmacology; D012477:Salmonella enteritidis / Q000187:drug effects* / Q000254:growth & development; D012973:Sodium Hypochlorite / Q000494:pharmacology; D013997:Time Factors
chemical_list: D002254:Carbonates; D004202:Disinfectants; D006878:Hydroxides; D017680:Potassium Compounds; C005686:sodium carbonate; D012973:Sodium Hypochlorite; C029943:potassium hydroxide