Examination of the eggshell cuticle and membranes on their impact of Salmonella Enteritidis or Typhimurium recovery from inoculated and stored eggs

Authors: Harris, Caitlin; Bartenfeld Josselson, Lydia; BOURASSA, DIANNA - Auburn University; Buhr, Richard - Jeff

Submitted to: Journal of Applied Poultry Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/27/2022
Publication Date: 10/3/2022
Citation: Harris, C.E., Bartenfeld Jossel, L.N., Bourassa, D.V., Buhr, R.J. 2022. Examination of the eggshell cuticle and membranes on their impact of Salmonella Enteritidis or Typhimurium recovery from inoculated and stored eggs. Journal of Applied Poultry Research. https://doi.org/10.1016/j.japr.2022.100297.
DOI: https://doi.org/10.1016/j.japr.2022.100297

Interpretive Summary: Interpretive Summary: The chicken eggshell’s outer coating, the cuticle, is believed to protect the egg contents from contaminating by restricting bacteria penetration of the eggshell. The results of altering the eggshell cuticle through mechanical or chemical disruption, as well as the impact of eggshell membranes and egg contents on post-inoculated Salmonella recovery was examined for this manuscript. Eggs were inoculated with Salmonella Enteritidis and Typhimurium serotypes at 10^5 to 10^6 CFU of Salmonella after the following treatments were applied: mechanically sanding-off the cuticle, chemically removing cuticle, eggshells empty of egg contents, inoculation into the air cell, and unaltered positive control. Post-inoculation eggs were stored at room temperature (22 to 25C) and eggshells were sampled at 1, 6, and 24 hr for recovery of Salmonella. Compared to unaltered control eggs, mechanical (sanding) and chemical (bleach or alcohol soak) stripping/damaging of the eggshell cuticle did not impact the recovery of Salmonella on intact eggs that were stored at room temperature for 1 to 24 hr. Eggshells with albumen and yolk removed (prior to shell inoculation) resulted in higher Salmonella recovery, indicating that the antimicrobial effects of the cuticle in the presence of albumen thru the 24 hr holding may be effective at Salmonella inhibiting contamination. For all experiments, Salmonella recovery from eggshells decreased as holding times increased (1 to 24 h), which is consistent with literature where inoculated eggs were stored at room temperature. When eggs are stored at room temperature, Salmonella reduction occurs more rapidly in 24 hr post-inoculation for control eggs compared to eggs with stripped cuticles, no egg contents (albumen and yolk), or when inoculated into the air cell. Overall, this study highlights the importance of eggshell cuticle, membranes, and albumen on the integrity of egg contents and the recovery prevention of inoculated Salmonella from eggshells contamination.

Technical Abstract: Abstract: The effect of altering eggshell cuticle, as well as the impact of eggshell membranes and egg contents, on inoculated Salmonella recovery was examined. Four experiments were performed with Experiments 1 and 2 utilizing Salmonella Enteritidis and Experiments 3 and 4 utilizing both Salmonella Enteritidis and Typhimurium. Eggs were inoculated with 10^5 to 10^6 CFU of Salmonella after the following treatments were applied: mechanically stripped cuticle, chemically stripped cuticle, eggshells empty of egg contents, inoculation into the air cell, and unaltered positive control. Post-inoculation eggs were stored at room temperature (22 to 25°C) and eggshells were sampled at 1, 6, and 24 h for recovery of Salmonella. Mechanically and chemically stripping eggshell cuticle from this study did not impact Salmonella recovery compared to unaltered positive control eggs. Eggshells with contents removed had significantly higher recovery of Salmonella over 24 h storage, as well as eggs that were inoculated in the air cell. For all experiments, Salmonella recovery decreased as holding times increased (1 to 24 h), which is consistent with literature where inoculated eggs were stored at room temperature. Results from Experiment 3 indicated that S. Typhimurium had higher recovery for all treatments and holding times compared to S. Enteritidis, except for eggshells without contents with 100% recovery at 1 h for both serotypes, and the recovery of both serotypes was similar in Experiment 4. Overall, this study highlights the importance of eggshell cuticle, membranes, and albumen on the integrity of egg contents and the recovery of inoculated Salmonella from eggshells.