Alternative Antimicrobial Commercial Egg Washing Procedures.

Area of Science:

• Food Microbiology
• Food Safety
• Agricultural Science

Background:

• Commercial table eggs undergo washing before packaging, typically using warm, alkaline water.
• Heating water for egg washing incurs significant energy costs for the industry.
• Developing a cool water washing method that ensures microbiological safety is desirable for cost reduction.

Purpose of the Study:

• To evaluate the efficacy of different wash procedures in reducing Salmonella contamination on shell eggs.
• To determine if ambient temperature washing can achieve comparable Salmonella reduction to the industry standard warm wash.
• To assess the potential for energy savings by using cooler water temperatures in egg washing.

Main Methods:

• Four wash procedures were tested: pH 11 at 48.9°C (standard), pH 11 at ambient temperature (~20°C), pH 6 at 48.9°C, and pH 6 at ambient temperature.
• Alkaline washes used potassium hydroxide detergent; acidic washes used chlorine (200 ppm) with a stabilizer (T-128).
• Eggs were inoculated with Salmonella Enteritidis and Salmonella Typhimurium via immersion and droplet methods.

Main Results:

• Immersion inoculation showed similar, slight Salmonella reduction across all treatments (~0.77 log CFU/ml).
• Droplet inoculation demonstrated significant Salmonella reduction (approx. 5 log CFU) with chlorine-based acidic washes (both temperatures) and the warm alkaline wash.
• Ambient temperature acidic washes performed comparably to the standard warm alkaline wash and were superior to ambient alkaline or control water treatments.

Conclusions:

• Ambient temperature acidic washes (pH 6 with chlorine and stabilizer) are a viable alternative to the standard warm alkaline wash for Salmonella reduction.
• This approach offers potential for reduced energy costs, extended shelf life, and slowed pathogen growth.
• Cooler water washing methods can maintain egg safety while improving economic and environmental efficiency in the egg industry.