| Salmonella enterica subsp. enterica serovar Enteritidis (Salmonella Enteritidis) is a food-transmitted pathogen responsible for salmonellosis. Poultry products are the primary vehicles for the transmission of the microorganism to man, and it is estimated that 50% of the foodborne cases are related to the consumption of contaminated egg or egg products. The objectives of this study were (a) to develop a procedure to inactivate Salmonella Enteritidis on the eggshell surface, at low temperatures, utilizing pressurized gaseous ozone in combination with ultraviolet radiation (UV); (b) to evaluate the feasibility of inactivating Salmonella within shell egg, with minimal impact on quality, using thermal pasteurization procedures, and (c) to develop a process to decontaminate shell eggs employing heat, vacuum, carbon dioxide, and ozone. Additionally, ozone penetration across the eggshell was investigated.; A procedure was developed to inactivate Salmonella Enteritidis within shell eggs using heat, vacuum, and pressurized gaseous ozone. Internally contaminated shell eggs (∼107 CFU/g egg) were heated at 57--59°C for up to 40 min, placed under vacuum (-7 to -10 psig), and subsequently treated with O3 (12--14% wt/wt; ≤20 psig) or with mixtures of O3 and CO2. Results indicated that heat, pressurized O3, and their combination significantly (p < 0.05) decreased Salmonella inside eggs. A response surface model was developed from data to optimize treatment conditions required to achieve 5-log 10 microbial inactivation. For example, shell eggs heated at 57°C for 25 min, subsequently placed under vacuum (-7 to -10 psig), and treated with O3 at 10 psig for 40 min, resulted in ≥6.3 log10 Salmonella reduction within shell eggs. Egg quality was not drastically affected after treatments with heat and O 3.; In addition, factors affecting ozone penetration across the eggshell were investigated using a colorimetric procedure. Clean eggshells, that were previously heated at 57°C for 30 min, were filled with a redox dye and subsequently treated with gaseous O3 at 0--10 psig for ≤40 min. Results indicated that time of ozonation (at 10 psig) and heating prior to applying O3 at 10 psig were significant (p < 0.05) for the penetration of the gas through the eggshell.; In conclusion, technology based on combinations of O3 and UV, or O3 and heat should be considered in the egg industry for future applications to produce Salmonella-free shell eggs. (Abstract shortened by UMI.)... |
