Effect of ultrasonic treatment on reduction of Esherichia coli ATCC 25922 and egg quality parameters in experimentally contaminated hens' shell eggs.

BACKGROUND: In this study, hen eggs which were experimentally contaminated with Esherichia coli ATCC 25922 were used. Contaminated eggs were washed statically (S5 to S30; 0 kHz) and by ultrasonic waves (U5 to U30; 35 kHz) for given applications of time (5, 15 and 30 min), then the eggs were stored at 22°C for 14 days. RESULTS: Depending on the time of ultrasonic application, a significant increase in egg shell strength (P < 0.01) was recorded. The highest value of the Haugh unit (67.93, 1 day) was observed on the eggs which were washed by ultrasonic waves. Yolk width values of ultrasonic washed eggs diminished. E. coli was completely removed by 30 min of ultrasonic application. During storage E. coli growth was not detected on the eggs which were washed by ultrasonic waves except the eggs in U5 group (2.04 log CFU eggshell⁻¹) on the first day of storage. CONCLUSION: Depending on the time of ultrasonic application a significant increase in egg quality parameters (shell strength, albumen height, Haugh units, and yolk height) were observed. The application of ultrasound led to a significant reduction in E. coli numbers on egg shells.

Differential forms of the Kramers-Krönig dispersion relations.

Differential forms of the Kramers-Krönig dispersion relations provide an alternative to the integral Kramers-Krönig dispersion relations for comparison with finite-bandwidth experimental data. The differential forms of the Kramers-Krönig relations are developed in the context of tempered distributions. Results are illustrated for media with attenuation obeying an arbitrary frequency power law (alpha(omega) = alpha0 + alpha1(absolute value of omega)y). Dispersion predictions using the differential dispersion relations are compared to the measured dispersion for a series of specimens (two polymers, an egg yolk, and two liquids) exhibiting attenuation obeying a frequency power law (1.00 < or = y < or = 1.99), with very good agreement found. For this form of ultrasonic attenuation, the differential Kramers-Krönig dispersion prediction is found to be identical to the (integral) Kramers-Krönig dispersion prediction.

Form and function of lacunae in the ovary of the laying hen.

BACKGROUND: Spontaneous atresia of large, yolky, ovarian follicles occurs in the chicken and in other species when the stimulus for ovulation ceases. This means that as much as 40 ml of yolk must be resorbed by the ovary if normal ovarian morphology is to be regained. This study examines the process of yolk resorption in the ovarian stroma following bursting atresia. METHOD: Light, transmission, and scanning electron microscopy were used to study the morphology of lacuna spaces and their changes in ovaries of broiler and layer breeds of domestic chicken, both in actively laying birds and in birds undergoing spontaneous or induced follicular atresia. A comparative study was made of the ultrastructural differences between lacuna-lining cells, blood-vessel endothelium, and germinal epithelium of the ovary. RESULTS: Transformation of lacuna-lining cells and peritoneal cells into macrophages occurred after bursting atresia and exposure of these cells to released yolk. Complete atresia of large yolky follicles occurred very quickly. CONCLUSION: The resorption of this large volume of yolk, at least in part, seems to be mediated by the transformed lacuna-lining cells.

Ultrasonographically detectable ring structure in avian (Gallus gallus) egg yolks.

After a preliminary finding of ultrasonographically detectable ring structure within the yolk of avian eggs, a study was initiated to investigate these properties. Ultrasonographically detectable alternating hyperechoic and hypoechoic rings within the egg yolk were found to be consistent but variability occurred in ring numbers, thickness, and clarity. Rings were best seen at two days post oviposition and were not affected by refrigeration or heating of the yolks. The usefulness of rings in experimental studies of yolk content of lipoprotein is postulated.