Sanitizing Hatching Eggs with Essential Oils: Avian and Microbiological Safety

Increased meat and egg production leads to concomitant changes in poultry practices, including the indiscriminate use of formaldehyde to sanitize hatching eggs. Although this sanitizer aids in the increase in poultry production, its toxic potential for man and for avian embryos represents an obstacle to its long-term use. This review assesses whether essential oils fit into the context of hatching egg contamination, reviewing their antimicrobial efficiency, toxicity to poultry embryos and chicks, and their sanitizing effects on poultry production parameters. Studies have indicated that, because they are safer, most of the essential oils studied can be a potential substitute for formaldehyde for minimizing microbial exposure of hatching eggs and embryos. However, complementary studies on the microbiological profile of embryos and chicks hatched from eggs sanitized with essential oils need to be carried out and the economic feasibility of the candidate products should also be considered.

The effect of neutral electrolyzed water as a disinfectant of eggshells artificially contaminated with Listeria monocytogenes

Neutral electrolyzed water (NEW) was tested as a disinfectant against Listeria monocytogenes on the surface of table eggs. Eggs were collected from a single Bovans White flock and were exposed to L. monocytogenes. Artificially contaminated eggs were divided into three different treatment groups: NEW, 2% citric acid solution (CAS), and saline solution (SS). To evaluate the bactericidal effect, the Mexican norm for antimicrobial activity determination protocol was performed. The observed bactericidal effect was compared against those obtained from CAS and SS. Bacterial cells present on the eggshells were quantified. NEW exhibited a significantly higher bactericidal effect than CAS when evaluated on the surfaces of chicken eggshells (6.11 log10CFU/ml reduction in vitro and a 2.18 log10 CFU/egg reduction on eggs vs. 1.06 log10CFU/ml in vitro reduction and 1.74 log10CFU/egg). Additionally, CAS was found to react with the carbonate egg shield, resulting in a loss of cuticle integrity. Mineral content of NEW-treated eggshells was similar to SS-treated eggshells; however, CAS-treated eggshells showed a significant decrease in phosphorous concentration compared to NEW treatment. In this study, we demonstrated the effect of NEW and CAS on the integrity of the L. monocytogenes wall using transmission electron microscopy. To the best of our knowledge, this is the first report of the effect of NEW against L. monocytogenes on eggshells. Our results show that NEW is a viable alternative solution for the disinfection of table eggs that does not affect the cuticle or shell.