A new, chemical- and heat-free egg processing technique developed by scientists at the University of Saskatchewan (USask) has been shown to effectively inactivate pathogens on eggshells while preserving eggs’ physical and nutritional quality.

The novel method involves treating eggshells with engineered water nanostructures (EWNS), which are generated via the application of tiny water droplets charged with high-voltage electricity.

To test the efficacy of the technique in killing foodborne pathogens, the researchers subjected inoculated eggs to the process, then recovered and analyzed remaining bacteria from the egg surfaces. The results showed that under EWNS operating conditions of 5 minutes of exposure time, 1 microliter (μL) per minute per needle of water flow rate, and 9.0 kilovolts per centimeter (kV/cm) of electric field strength, a maximum inactivation efficiency of 97.6 and 80.4 percent can be achieved for egg surfaces contaminated by Escherichia coli and Salmonella, respectively.

After processing, the eggs were scanned using an ultra-bright synchrotron light to produce highly detailed 3D X-rays, a technology at Canada's national synchrotron light source facility, Canadian Light Source (located at USask). The scans confirmed that the new technique does not damage the egg cuticle or shell, both of which provide natural protection against harmful microbes. This provides an advantage over traditional thermal and chemical decontamination processes, which can degrade the egg cuticle and shell.

The novel processing technique shows promise as a low-cost, environmentally conscious solution for industry. Moving forward, the scientists will explore how the technology can be scaled for commercial use.

Funding for this project was granted by the Natural Sciences and Engineering Research Council of Canada, the Saskatchewan Ministry of Agriculture, and the Canadian Poultry Research Council.