Abstract
ABSTRACT This study evaluated the influence of the bird’s age on the quality of the shell and percentage of bacterial penetration in commercial eggs. White-shelled commercial eggs were used, laid by light laying hens in their first laying cycle at 21, 39, 51, and 62 weeks of age. Shell quality evaluations comprised: egg weight, specific gravity, percentage and thickness of shell, number and size of pores. For evaluations regarding bacterial penetration, strains of several enterobacterias and one salmonella were used, all of which resistant to Nalidixic acid (100µg/ml). The method employed for evaluation of bacterial penetration was filling the eggs with growth medium. The data were subjected to variance analysis with 5% of probability using SAS (Education Analytical Software, 2013). Eveb though increase in the laying hen's age caused reduction of the quality of eggshells, it failed to affect the percentage of penetration of the bacterial samples evaluated.
Highlights
The eggshell works as natural packaging to internal components by acting as a physical barrier, hampering pathogenic penetration and excessive water loss (Barbosa et al, 2012).As laying hens grow older, they lay eggs with larger weight and surface, and thinner shells (Raghiante et al, 2010; Swiatkiewicz et al, 2015)
Bacterial contamination of the eggs may occur in two possible ways: vertical, during egg formation in the bird’s reproductive tract; or horizontal, through contact of egg with feces, bedding, nest, collector’s hands, trays, and contaminated surfaces, the latter being the main mode of pathogen transmission in eggs for human consumption (Mendes et al, 2014)
This study aims to evaluate the influence of the laying hen’s age in eggshell quality and incidence of bacterial penetration through shell pores by filling the eggs with growth medium
Summary
The eggshell works as natural packaging to internal components by acting as a physical barrier, hampering pathogenic penetration and excessive water loss (Barbosa et al, 2012).As laying hens grow older, they lay eggs with larger weight and surface, and thinner shells (Raghiante et al, 2010; Swiatkiewicz et al, 2015). Since no laws in effect require stores to keep eggs for human consumption refrigerated, they are kept in room temperature from the moment they are laid to the moment they are bought, being, in some cases, refrigerated only at the consumer's house (Xavier et al, 2008). This lack of refrigeration throughout the production chain along with alterations in shell quality elevate the risks of human infection by pathogens that can reach the internal content of the eggs and arrive at the consumer’s plate (Pinto and Silva, 2009)
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