Eggs are widely consumed around the world, but eggs can be contaminated with microorganisms that may transmit food-borne diseases to consumers. To reduce this risk, eggs are washed during processing in many countries. However, some studies have suggested that traditional chemical cleaners may leave residues and can be inactivated by organic matter on the eggshell surface.
Wanting to investigate an environmentally friendly cleaning and disinfecting agent to remove bacteria and feces from eggshells, a group of researchers in China studied the efficacy of using electrolyzed reduced water (ERW) to remove organic matter from shells followed by slightly acidic electrolyzed water (SAEW) to sanitize eggs without compromising egg quality. Salmonella Enteritidis was used as a test bacterial contaminant because it is commonly used as an indicator bacteria in egg disinfection.
They reported their results in a recent issue of Poultry Science.
SAEW has a near-neutral pH and is considered a promising disinfectant for eggs due to high antimicrobial efficacy and low human health impact. ERW has high pH, high dissolved hydrogen and low oxidation/reduction potential and is used as a cleaning agent on various surfaces such as cutting boards and kitchen utensils.
The researchers noted that many disinfectants and detergents may remove the protective cuticle from the egg, which can affect the quality of eggs during storage. Therefore, they included measures of egg quality during storage in the study.
According to the study results, ERW was more effective than deionized water in removing organic material from the egg surface. SAEW also removed chicken fecal liquid from the surface of eggs, showing some removal capacity for manure despite low efficiency.
ERW also was significantly more effective than deionized water in removing bacteria from the egg surface, which may be due to its decontaminating effect. The researchers noted that ERW may also have a limited bactericidal effect.
The researchers observed no significant difference between the SAEW-treated group and the ERW+SAEW-treated groups in complete removal of Salmonella from the egg surface, and both treatments were significantly superior to the deionized water and ERW treatments for disinfecting eggs.
Regarding egg quality parameters during storage, both the ERW+SAEW and SAEW treatments were effective in preventing the decrease in Haugh units and Yolk index and the increase in albumen pH due to better decontamination and bacterial inactivation. That said, SAEW contributed to greater rate of weight loss due to the effect of SAEW on the surface cuticle of the eggshell. The combination of ERW and SAEW compensated for this effect, allowing the advantages of each treatment to be fully exploited, the researchers concluded.
What does this mean for producers?
The full paper, “Effect of combined electrolyzed reduced water and slightly acidic electrolyzed water spraying on the control of Salmonella, eggshell quality, and shelf life of eggs during storage,” can be found in Poultry Science and online here.
DOI: 10.1016/j.psj.2024.104012
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