Comparison of quality attributes of shell eggs subjected to directional microwave technology

Data mining-based discriminant analysis as a tool for the study of egg quality in native hen breeds

Despite the wide biodiversity of avian species of zootechnical interest in Spain, projects aimed at characterizing these genotypes and their products are necessary. External and internal egg quality traits were measured in 819 eggs laid by hens of 10 different genotypes: White, Franciscan, Black and Partridge varieties of Utrerana, Blue Andalusian, Spanish White-Faced, Andalusian Tufted White and Black varieties, Araucana; and Leghorn Lohmann LSL-Classic lineage (commercial hybrid line) hen breeds. After multicollinearity analysis of egg quality-related traits was performed (VIF ≤ 4), major diameter, minor diameter, egg weight, and albumen height were deemed redundant explanatory variables and discarded. A stepwise discriminant canonical analysis was developed to cluster eggs across hen genotypes considering egg quality attributes. Shell a* and b* variables reported the highest discriminant power (Wilks' lambda: 0.699 and 0.729, respectively). The first two discriminant functions captured 60.48% of the variance across groups (F1: 39.36%; F2: 21.12%). Clear quality differentiation signs are evidenced for Mediterranean native breeds' eggs when compared to Leghorn's eggs. Consequently, this evidence of egg quality differentiation may favor the standardization of breed- and variety-linked distinctive products, which may open new market opportunities based on the existence of a wide spectrum of diet or culinary applications.

Discriminant Canonical Analysis as a Validation Tool for Multivariety Native Breed Egg Commercial Quality Classification

This study aimed to develop a tool to validate multivariety breed egg quality classification depending on quality-related internal and external traits using a discriminant canonical analysis approach. A flock of 60 Utrerana hens (Franciscan, White, Black, and Partridge) and a control group of 10 Leghorn hens were placed in individual cages to follow the traceability of the eggs and perform an individual internal and external quality assessment. Egg groups were determined depending on their commercial size (S, M, L, and XL), laying hen breed, and variety. Egg weight, major diameter, minor diameter, shell b*, albumen height, and the presence or absence of visual defects in yolk and/or albumen showed multicollinearity problems (variance inflation factor (VIF) > 5) and were discarded. Albumen weight, eggshell weight, and yolk weight were the most responsible traits for the differences among egg quality categories (Wilks’ lambda: 0.335, 0.539, and 0.566 for albumen weight, eggshell weight, and yolk weight, respectively). The combination of traits in the first two dimensions explained 55.02% and 20.62% variability among groups, respectively. Shared properties between Partridge and Franciscan varieties may stem from their eggs presenting heavier yolks and slightly lower weights, while White Utrerana and Leghorn hens’ similarities may be ascribed to hybridization reminiscences.

Salmonella enteritidis in shell eggs: evolving concerns and innovative control measures

The issue of egg contamination with Salmonella enterica serovar Enteritidis rose to prominence several decades ago with increasing rate of infection around the world. Recent outbreaks have assured that this problem maintains a place in the public consciousness. Extensive research has been conducted to investigate the factors precipitating contamination events, their avoidance, and mitigation of the threat of contaminated eggs; consequently, regulations have been put in place to increase the safety of shell eggs. Despite these measures, rate of illness remains significantly higher than projected goals. This chapter includes information regarding the contraction of Salmonella species by laying hens and the subsequent deposition of these cells in shell eggs. Particular attention will be given to the prevalence of Salmonella Enteritidis in eggs and egg-containing products relative to other salmonellae. Research has been conducted to elucidate the mechanisms behind the fitness of Salmonella Enteritidis strains for this environment, but a consensus has yet to be reached. Novel methods of sanitizing shell eggs also are reviewed.