Efficacy of slightly acidic electrolyzed water on the microbial safety and shelf life of shelled eggs

Abstract

This study evaluated the efficacy of slightly acidic electrolyzed water (SAEW) for the inactivation of Salmonella Enteritidis and Escherichia coli on shelled eggs as well as studied the shelf life and internal quality attributes (i.e., weight loss, Haugh unit, yolk index, albumen pH, and yolk pH) of eggs during storage at 25°C. The decontamination test egg samples (freshly laid) were inoculated and immersed for 1, 2, 3, and 4 min in each treatment (i.e., SAEW, acidic electrolyzed water, NaClO solution, and sterile deionized water) at available chlorine concentrations (ACCs) of 10, 18 and 26 mg/L. The storage test eggs (freshly laid) were immersed for 3 min in 4 treatments (i.e., SAEW, acidic electrolyzed water, NaClO solution, and no treatment) and stored for 30 D at 25°C. The effects of the SAEW on microbiological qualities and freshness parameters were investigated. Decontamination of eggs with SAEW showed an equivalent or higher bactericidal effect compared to other treatments. A complete inactivation of S. Enteritidis and E. coli on the surface of shelled egg samples resulted from treatment with SAEW at an ACC of 26 mg/L for 3 and 4 min, respectively. Almost all of the egg quality parameters investigated in the present study were significantly (P < 0.05) affected by the storage time. As storage time increased, the yolk index and Haugh unit value decreased, and weight loss, albumen pH, and yolk pH increased. However, SAEW treatment minimized weight loss (5.52%) and preserved the albumen and yolk quality better than no treatment at 25°C. Relative to acidic electrolyzed water and NaClO solution, the advantages of SAEW are reduced corrosion of egg surfaces and potentially less water and CO2 escaping from eggshell pores. The results highlight the promising use of SAEW to enhance the microbial safety and to extend the shelf life of shelled eggs. Future combined methods with SAEW and other treatments are also needed.

Keywords: microbial safety; shelf life; shelled eggs; slightly acidic electrolyzed water.