Assessment of the efficacy of stable liquid chlorine dioxide (CLO2) in disinfection of stored table eggs

Abstract

Microbiological contamination of table egg shells poses an important
public health and technological challenge, particularly in the European
Union, where washing and disinfection of Class A eggs are prohibited
due to adverse effects associated with previously used sanitising
agents. This study evaluated the efficacy of stable liquid chlorine
dioxide (ClO₂) in reducing microbial load on eggshells during storage
under commercial conditions. A total of 200 eggs were divided
into two groups: a control group (untreated) and an experimental
group treated with a fine aerosol of 50 ppm ClO₂. Microbiological
cleanliness was assessed using total aerobic mesophilic bacterial count
(UBAMB) and luminometry at predetermined intervals.Immediately
after treatment (day 0), the experimental group showed a pronounced
microbiological reduction, with median UBAMB values decreasing
from 35,000 CFU in the control group to 70 CFU in the treated group
(p = 0.029). Significant differences in luminometry values between
the groups were observed on days 0 and 14 (p = 0.028; p = 0.025),
indicating sustained antimicrobial activity during storage. Within the
experimental group, luminometry values showed significant temporal
variation (p = 0.015), characterised by an increase by day 7, followed
by stabilisation by day 14, when values returned to levels comparable
to those observed immediately after disinfection (p = 0.980). No
significant temporal changes were detected in the control group (p =
0.276). Stable liquid chlorine dioxide proved to be an effective and
technologically acceptable disinfectant, achieving significant microbial
reduction without compromising egg integrity. These findings highlight
the potential applicability of ClO2 as a modern, non-destructive
sanitising option that addresses microbiological safety concerns while
meeting the hygienic and regulatory requirements related to table egg
production. Further research is recommended to assess the internal
quality of eggs and to explore broader microbiological indicators
under varying storage and environmental conditions.