Inactivation of Salmonella Enteritidis on Hatchery and Table Eggs Using a Gas-phase Hydroxyl-Radical Process

• Published in: Journal of food protection Vol. 86; no. 12; p. 100189
• Main Authors: Zai, Brenda, Comacho-Martinez, Vanessa, Hasani, Mahdiyeh, Warriner, Lara Jane, Koutchma, Tatiana, Keener, Kevin, Marcone, Massimo, Warriner, Keith
• Format: Journal Article
• Language: English
• Published: United States Elsevier 01.12.2023
• Subjects: Animals; Chickens; Colony Count, Microbial; Decontamination; Eggs; Food Microbiology; Hatchery; Hydrogen peroxide; Hydrogen Peroxide - pharmacology; Hydroxyl-radical; Ozone - pharmacology; Salmonella; Salmonella enteritidis; Salmonella; Hydroxyl-radical; Hydrogen peroxide; Hatchery; Decontamination; Eggs
• ISSN: 0362-028X; 1944-9097
• DOI: 10.1016/j.jfp.2023.100189

Eggs represent a significant vehicle for Salmonella Enteritidis with the pathogen being transferred to chicks in the hatchery, or to consumers via table eggs. In the following, the efficacy of a gas-phase hydroxyl-radical process for decontaminating hatchery and table eggs was evaluated. Recovery of Salmonella was maximized through holding eggs in tryptic soy broth containing 20% w/v glycerol for 1 h prior to plating. By using this technique, it was possible to recover 63% of the theoretical Salmonella inoculated onto eggs. The continuous hydroxyl-radical reactor consisted of a bank of UV-C lamps (254 nm) that generated hydroxyl-radicals from the degradation of hydrogen peroxide (H O ) mist and ozone gas. The optimal treatment was defined as that which supports a 5 log CFU/egg reduction of Salmonella without negatively affecting egg quality or leaving H O residues. A process of 2% v/v H O delivered at 30 mL/min with a UV-C dose of 19 mJ/cm and ozone (20 ppm) with a total treatment time of 10s was selected. The egg quality metrics (Haugh value, yolk index, albumin pH, yolk pH) did not negatively differ over a 35-day shelf-life at 4 or 25℃ compared to washed eggs or nontreated controls. The cuticle layer of eggs remained intact following hydroxyl-radical treatment. Fertilized eggs (n = 61) treated with the hydroxyl-radicals exhibited the same hatchery rate (75%) as nontreated controls (71-79%) with no defects (unhealed navels or red hocks) being observed. The same hydroxyl-radical treatment could be applied to table eggs to support >5 log CFU/egg reduction of Salmonella and was compatible with egg washing regimes practiced in industry. In comparison, the egg washing process based on sodium hydroxide and chlorine supported a 2.76 ± 0.38 log CFU/egg reduction of Salmonella. The hydroxyl-radical treatment represents a preventative control step to reduce the carriage of Salmonella on hatchery and table eggs.