Antimicrobial defenses of table eggs: Importance of antibacterial proteins in egg white as a function of hen age in an extended production cycle
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Jabalera Ruz, Ylenia María; Domínguez Gasca, Nazaret; Muñoz, Arantxa; Jiménez López, Concepción; Rodríguez Navarro, AlejandroEditorial
Elsevier
Materia
Egg white Hen Antimicrobial proteins Bacterial contamination UPLC-Mass spectroscopy
Date
2022-06-14Referencia bibliográfica
Ylenia Jabalera... [et al.]. Antimicrobial defenses of table eggs: Importance of antibacterial proteins in egg white as a function of hen age in an extended production cycle, Food Microbiology, Volume 107, 2022, 104068, ISSN 0740-0020, [https://doi.org/10.1016/j.fm.2022.104068]
Sponsorship
Spanish Government CGL 2015-64683-P; Premio de Investigacion 2019 (Instituto del Huevo); Junta de Andalucia RNM-938; Natural Sciences and Engineering Research Council of Canada (NSERC) RGPIN2022-04410Abstract
The importance of egg natural defences to prevent bacterial contamination and their relation with hen age in
extended production cycles were evaluated. Egg-white from eggs of different hen age groups (up 100-weeks-old)
and lines (Hy-Line white and brown) were inoculated with Gram-positive Staphylococcus aureus or Gram-negative
Salmonella Typhimurium, ranging from 103-106 CFU/mL. Our results show that concentrations of egg-white
lysozyme and, particularly, ovotransferrin are important to modulate bacterial survival in a dose-dependent
matter. Depending on protein concentration, their effect ranges from bactericidal to bacteriostatic, with a
threshold for bacterial contamination that depends also on hen age and line. The concentrations of lysozyme and
ovotransferrin increased with hen age (up to 2 and 22 w/w% of total protein, respectively), and eggs laid by
older hens exhibited the greatest potential to prevent the growth of the highest Salmonella inoculum (106 CFU/
mL). Salmonella-penetration experiments demonstrated that non-contaminated eggs display significantly higher
concentrations of antimicrobial proteins. However, eggs from older hens needed a higher concentration of these
proteins (>20% ovotransferrin) to prevent bacterial contamination, showing that antimicrobial protein concentrations
in egg-whites was not the only factor influencing bacterial contamination. Finally, this study
demonstrated that egg-white of eggs produced by old hens are less prone to contamination by Salmonella.