Location: Egg Safety and Quality
Title: Comparison of vitelline membrane strength amongst breeds of commercial layers Authors
|Anderson, K - N.C. STATE, POULTRY SCI|
Submitted to: Poultry Science
Publication Type: Abstract Only
Publication Acceptance Date: February 28, 2007
Publication Date: July 8, 2007
Citation: Jones, D.R., Anderson, K.E. 2007. Comparison of vitelline membrane strength amongst breeds of commercial layers (abstract). Poultry Science.p.86:379-380(Suppl 1) Technical Abstract: The strength and elasticity of the vitelline membrane is important for both food safety and product quality concerns. The strength of the membrane has been associated with the ability of microorganisms to enter the nutrient rich yolk. Also, contamination of commercially prepared albumen with yolk during separation can lead to greatly diminished albumen functionality. A study was conducted to determine the strength and elasticity of the vitelline membrane of eggs from six strains of commercial laying hens (3 white, 3 brown). Two different probes were utilized to assess the membrane: 75 mm disc (2.0 g trigger force) and 1 mm, rounded end probe (0.2 g trigger force). Eggs were collected on three consecutive days from layers which were part of the North Carolina Layer Management and Performance Test. All eggs were stored at 4C until tested 5 d after lay. A TA.XTplus Texture Analyzer with a 750g load cell and test speed of 1mm/s was utilized for all measurements. Twelve eggs from each strain were tested daily for each probe. Force measurements for the disc ranged from 132.43 – 173.08 g (P < 0.05) with elasticities of 8.25 – 9.49 mm (P < 0.01). The 1 mm probe recorded average force measurements of 2.26 – 2.60 g (P < 0.01) and elasticities of 2.87 – 6.78 mm. Both probes identified the same strain of layers as producing eggs with the lowest vitelline membrane strength and the least elastic membrane. Force measurements recorded by the disc were much greater and were more closely associated with the linear detection region of the load cell. The disc probe allowed for a more complete assessment of membrane strength than the 1 mm probe due to the high percentage of the membrane having the force exerted upon it. The 1 mm probe could provide insight into the strength at a single point on the membrane where bacteria could attack. The choice of testing probe can have a direct effect on the outcome of the results and should be based on the precise quality concern being targeted.