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

Abstract

SUMMARY: 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 105 to 106 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 egggshell positive control. Post-inoculation eggs were stored at room temperature (22–25°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 (P ≤ 0.05). For all experiments, Salmonella recovery decreased as holding times increased (1–24 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. 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.

Keywords

• Salmonella spp.
• eggshell cuticle
• eggshell innoculation
• eggshell recovery