SEARCH · PubMed Health

Results for “shell”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,243 records · Page 69Linked to original sources

PubMed2002

Parametric analysis of cryogenic carbon dioxide cooling of shell eggs.

Parametric analysis of cryogenic cooling of shell eggs was performed using finite element analysis. Two cooling temperatures (-50 and -70 C), three cooling convective heat transfer coefficients (20, 50, and 100 W/ m2K), two equilibration temperatures (7 and 25 C), and two equilibration heat transfer coefficients (0 and 20 W/ m2K) were considered in the analysis. Lower temperatures and higher cooling convective heat transfer coefficients resulted in higher cooling rates and lower final egg temperatures. A chart and equation were developed to identify combinations of processing parameters to yield the desired egg temperature (7 C) at the end of adiabatic equilibration. Results show that a cooling time of 8.2 min was required to reach a final egg temperature of 7 C for a cooling temperature of -50 C and a convective heat transfer coefficient of 20 W/m2K. The cooling time decreased to 2 min when the convective heat transfer coefficient increased to 100 W/m2K, at a cooling temperature of -50 C. Processing at -70 C and 20 W/m2K, required 5.3 min to reach a final temperature of 7 C. At a higher convective heat transfer coefficient (100 W/m2K) and -70 C, a processing time of 1.3 min was sufficient to reach the target temperature of 7 C. The results may be used as a reference in process or equipment design for shell egg cooling in cryogenic CO2.

Animals↗

PubMed2002

Effects of cryogenic cooling of shell eggs on egg quality.

This study was conducted to investigate the effects of cryogenic cooling on shell egg quality. Gaseous nitrogen (GN), liquid nitrogen (LN), and gaseous carbon dioxide (GC) were utilized to rapidly cool eggs in a commercial egg processing facility and were compared to traditional cooling (TC). A modified food freezer was attached to existing egg processing equipment in order to expose eggs to the selected cryogen. In Experiment 1, eggs were treated with GN, LN, and TC then stored and tested over 10 wk. Experiment 2 eggs were treated (GC and TC) and evaluated for 12 wk. Quality factors that were measured included Haugh units, vitelline membrane strength and deformation at rupture, and USDA shell egg grades for quality defects. Haugh unit values were greater for cryogenically treated eggs as compared to traditionally cooled eggs (Experiment 1: 73.27, GN; 72.03, LN; and 71.4, TC and Experiment 2: 74.42, GC and 70.18, TC). The percentage of loss eggs in the GN treatment was significantly (P < 0.01) greater than those of the LN and TC treatments. Vitelline membrane strength was greater for the cryogenically cooled eggs versus traditional processing. Vitelline membrane breaking strength decreased over storage time. Vitelline membrane deformation at rupture was significantly (P < 0.05) greater for the cryogenically cooled eggs compared to the traditional eggs in each experiment. Use of the technology could allow for egg quality to be maintained for a longer time, which could increase international markets and potentially lead to extended shelf lives.

Air↗

PubMed2006

The effect of a commercial UV disinfection system on the bacterial load of shell eggs.

AIMS: To study the effect of UV irradiation on the bacterial load of shell eggs and of a roller conveyor belt. METHODS AND RESULTS: The natural bacterial load on the eggshell of clean eggs was significantly reduced by a standard UV treatment of 4.7 s; from 4.47 to 3.57 log CFU per eggshell. For very dirty eggs no significant reduction was observed. Eggs inoculated with Escherichia coli and Staphylococcus aureus (4.74 and 4.64 log CFU per eggshell respectively) passed the conveyor belt and were exposed to UV for 4.7 and 18.8 s. The reduction of both inoculated bacteria on the eggshell was comparable and significant for both exposure times (3 and 4 log CFU per eggshell). Escherichia coli was reduced but still detectable on the conveyor rollers. The internal bacterial contamination of eggs filled up with diluent containing E. coli or S. aureus was not influenced by UV irradiation. CONCLUSIONS: There is a significant lethal effect of UV irradiation on the bacterial contamination of clean eggshells and recent shell contamination, contamination of rollers can be controlled and the internal contamination of eggs is not reduced. SIGNIFICANCE AND IMPACT OF THE STUDY: The penetration of UV into organic material appears to be poor and UV disinfection can be used as an alternative for egg washing.

Animals↗

PubMed1980

Comparison of p-p'-DDE and o-p'-DDE on eggshell thickness and Ca binding activity of shell gland in ducks.

One of the main ecotoxicological effects of DDT and its stable metabolite DDE is to reduce the reproductive success in several species of birds by decreasing the thickness of the eggshell. In two different strains of ducks (Anas platyrhynchos var.) addition of 40 mg/kg dry weight of p-p'-DDE to the diet for 45 days produced a significant and long-lasting reduction of the shell thickness, measured as eggshell index. The reduction was more marked in Indian Runner Ducks (IRD; 30 +/- 3%) than in a Swedish X Rouen breed (SR; 10 +/- 2%. The p-p'-DDE residues in the egg yolk + egg white were almost similar in the two strains; 38 +/- 2 and 51 +/- 6 p.p.m. (wet weight) respectively. In the IRD 40 mg/kg of o-p'-DDE in the diet for 45 days was much less potent in reducing the eggshell index (8 +/- 3%) than the p-p' isomer; the amount of residue of the o-p' isomer in the eggs (2.2 +/- 0.1 p.p.m.) was also smaller. A homogenate of the shell gland from the SR breed accumulated 45Ca2+ in the presence of ATP. The accumulation was inhibited about 50% by 5 mM sodium azide and 100% by 3 mM mersalyl. p-p'- and o-p'-DDE in the incubation medium both reduced the Ca2+ binding, in a similar and dose-dependent manner. The threshold concentration was about 20 p.p.m.; 40 p.p.m. reduced the accumulation by about 40%. DDE may reduce eggshell thickness by inhibiting the Ca binding to the membranes of the cells of the eggshell gland.

Animals↗

PubMed1975

Egg production, shell thickness, and other physiological parameters of laying hens affected by T-2 toxin.

T-2 toxin has been reported to cause severe oral lesions and neural disturbances in young broiler chickens. T-2 toxin, when added at a level of 20 mug per g of feed, caused oral lesions but no abnormal neural disturbances in young broiler chickens. T-2 toxin, when added at a level of 20 mug per g of feed, caused oral lesions but no abnormal neural symptoms in laying hens. T-2 toxin had no effect on either hemoglobin, hematocrit values, erythrocyte count, plasma glucose, prothrombin times, or the sizes of the liver, spleen, pancreas, and heart. Lipid content of the liver was not altered. Feed consumption, however, was reduced, as were the total plasma protein and lipid concentrations and the total leukocyte count. Most important economically was the lowered egg production and a thinner egg shell. The timing and severity of the symptoms suggest that T-2 toxin causes primary oral lesions that reduce feed consumption with a consequent reduction in serum proteins and lipids, which culminate in decreased egg production. The leucopenia and thinner egg shell may be independent systemic effects of T-2 toxin in laying hens.

Animals↗

PubMed2006

Improved physical and biochemical features of a collagen membrane by conjugating with soluble egg shell membrane protein.

Soluble egg shell membrane protein (SEP) prepared from the egg shell membrane by performic acid oxidation and pepsin digestion was applied to prepare a membrane conjugated with pepsin-solubilized collagen (PSC) by cross-linking with water-soluble carbodiimide. SEP enabled a conjugated membrane to be constructed with a well-developed network structure having thicker collagen fibrils and higher stability than the PSC membrane alone, as indicated by reduced solubility and collagenase-digestion, increased denaturation temperature, and superior flexibility. The SEP-PSC membrane (SEP:PSC of 1:1, w/w) had lower sweatiness than the PSC membrane. Fibroblasts and keratinocytes adhered to the SEP-PSC-coated wells (SEP:PSC of 1:10, w/w) as a fundamental model of an artificial skin similar to that to the PSC-coated wells due to similar expression level of several cell-adhesion proteins. An SEP-PSC coating accelerated the cell growth of fibroblasts, whereas the cell growth of keratinocytes did not change, or decreased slightly due to more rapid differentiation indicated by a more substantial expression of differentiation marker proteins than a PSC-coating without SEP.

Animals↗

PubMed1991

[Chick embryo culture using duck egg shell--first successful hatch ].

The suitability of duck egg shell (DES) for chick embryo culture was investigated. Chick embryos were transferred into DESs with all egg contents after 3 days of normal incubation and cultured. The vessels made of polyethylene cling film were used for shell-less control. Among 35 embryos cultured in DESs, 21 survived until 16 days of incubation (13 days after transfer) and finally 3 newly hatched chicks were obtained at 22 days of incubation. One of them died 4 days later, but remaining two became full-grown cocks showing normal body weight and production of fertile sperms. Among 37 embryos cultured in polyethylene vessels, none survived over the period of 19 days of incubation. It is suggested that DES culture system may be useful for the various experiments using chick embryos.

Animals↗

PubMed1975

Improved hatch rate in helium-oxygen by reducing shell diffusion area.

For eggs incubating in a He atmosphere (79% He/21% O2), covering approximately 50% of the shell with melted paraffin improves hatch rate to control values (from 20% to 74%) and decreases egg weight loss to control values (from 17% to 9%). In air (79% N2/21% O2) the same paraffin treatment depresses hatch rate. The role of the inert gases in incubation appears to be an indirect one related to their modification of the rate of gaseous flux across the shell with the adverse effects of He due to excessively rapid diffusion.

Air↗

PubMed1989

A diabetic-like condition of turkey embryos maintained in shell-less culture.

Serum insulin concentration and pancreatic insulin content were determined for turkey embryos incubated in ovo and in long-term shell-less culture (ex ovo). Insulin was undetectable (less than 10 pg) in serum from 87% of the ex ovo embryos compared with their in ovo counterparts. This was evident at all incubation ages, although insulin was detectable in more of the ex ovo embryos on Day 24. Insulin increased in the embryos incubated in ovo from 122 (Day 15) to levels exceeding 2000 pg/ml at hatching. Total pancreatic insulin content was greater in the cultured embryos on Days 15, 17, and 22 compared with their in ovo counterparts. Serum glucose was significantly greater (P less than 0.05) in the ex ovo embryos at all ages. In response to an infusion of L-arginine, serum insulin increased from 566 to 1256 pg/ml in the in ovo embryos, whereas no change was evident in the ex ovo embryos (233 vs 257 pg/ml). When embryos incubated in ovo were injected with insulin, a significant (P less than 0.05) reduction of serum glucose was observed at 60 min after injection. Serum glucose concentrations remained elevated in the embryos incubated ex ovo despite the insulin injection. Liver glucose 6-phosphatase activity, assessed on Days 15 and 22 of incubation, was found to be significantly (P less than 0.05) lower in the ex ovo embryos. Turkey embryos incubated in shell-less culture exhibited chronic hyperglycemia in concert with extremely low circulating levels of insulin. The pancreatic beta cells of these embryos were not responsive to arginine or elevated glucose. Taken together these findings suggest the occurrence of a diabetic-like condition in the ex ovo embryos. This defect in insulin secretion may, in part, be responsible for some of the developmental abnormalities characteristic of the turkey embryo cultured ex ovo.

Animals↗

PubMed1983

The influence of dietary phosphorus level on laying hen performance, egg shell quality, and various blood parameters.

The influence of dietary phosphorus on hen performance and egg shell quality was investigated. Total dietary phosphorus levels of .17, .23, .30, .40, .50, .70, 1.50, and 2.30% were fed to four body weight groups of 23-week-old White Leghorn hens. Hens consuming the diets containing .17, .23, and .30% phosphorus, all from plant origin, consumed significantly (P less than or equal to .05) less feed, which resulted in poorer performance than hens fed diets supplemented with inorganic phosphorus. Addition of supplemental inorganic phosphorus at levels of .10 to .40% resulted in the best overall hen performance. Plasma phosphorus was directly related to dietary phosphorus level. Egg shell quality as measured by specific gravity was inversely related to dietary phosphorus levels above .50%.

Animals↗

PubMed1985

Calcium and its relationship to excess feed consumption, body weight, egg size, fat deposition, shell quality, and fatty liver hemorrhagic syndrome.

In Experiment 1, Hyline W36 caged hens were fed diets containing 1.7, 2.9, 3.5, and 4.1% calcium for 10 and 16 weeks. In Experiments 2 and 4, Dekalb XL and Hyline W36 pullets were fed diets containing 1.0, 1.7, and 3.75% calcium for 3 weeks (Exp. 2) or until 25 pullets from each group laid 7 eggs (Exp. 4). In Experiment 3 and 5, Dekalb and Hyline hens were fed diets containing 1.5 (Dekalb only), 1.75, 2.25, 2.75, and 3.75% calcium for 8 weeks. Criteria were liver, fat pad, egg and shell weights, egg specific gravity, production, feed consumption, liver fat and fatty acid composition, liver hemorrhage score, and body weight. As percent dietary calcium decreased, Hyline birds (Exp. 1, 4, and 5) had increased liver fat, body weight (except Exp. 4), and feed consumption, but egg specific gravity and shell weight decreased. Reduced dietary calcium levels had no effect on egg production in Experiment 1 but significantly reduced production in Experiment 5. Liver hemorrhage score significantly increased as percent dietary calcium decreased (Exp. 1). As dietary calcium decreased, Dekalb pullets (Exp. 2) had increased feed consumption, fat pad weight, and liver hemorrhage score. There was no increase in liver fat. However, in Dekalb hens (Exp. 3), feed consumption and egg production were significantly decreased as dietary calcium decreased. It is concluded that overconsumption caused by feeding pullets or hens inadequate calcium had no beneficial effect on egg size or egg production and, depending on strain, increased liver fat, liver hemorrhage score, body weight, and fat pad weight.

Adipose Tissue↗

PubMed1987

Relationship of parents' age, hatching egg weight, and shell quality to day-old chick weight as influenced by oviposition time.

This study was conducted with 840 eggs from commercial breeder hens to determine relationship of parents' age, egg weight, and to oviposition time and shell quality and day-old chick weight. Results indicate that eggs laid in the afternoon were significantly smaller with significantly better shell quality than those laid in the morning (64.1 vs. 64.5 g and specific gravity of 1.077 vs. 1.074, respectively). Also, chicks from afternoon eggs tended to weigh significantly less than those from morning eggs. However, the egg weight: chick weight ratio was not significantly affected by oviposition time; it was the same for morning and afternoon eggs (70.7 vs. 70.1%). The linear relationships between egg weight, age, and chick weight or between egg weight and chick weight were strong (R2 = .78 to .91), but the associations between specific gravity and chick weight were weaker (R2 = .28 to .24). It was possible to use both parents' age and egg weight or egg weight alone to predict chick weight for chicks hatched from morning and afternoon eggs.

Aging↗

PubMed2001

Laying season and egg shell cracks on the growth of Salmonella enteritidis in the egg albumen during storage.

We studied the effects of laying seasons and egg shell cracks on the ability of egg albumen to support the growth of Salmonella Enteritidis (SE) in eggs. Hens eggs used were those laid in February, June, and October in a farm in Japan and stored at 10, 20, and 30 degrees C, and at 30 degrees C after storage at 10 degrees C, immediately after receipt or after cracking the shell. At several-day intervals during storage, the egg contents were poured into a dish, SE was inoculated into albumen, and then the growth of SE during 3 days incubation at 18 degrees C was measured. The results demonstrated that storage temperature and laying season affected the growth of SE in the egg albumen. The proportion of eggs upon which albumen allowed the growth of SE was higher in the eggs stored at 30 degrees C than those stored at 10 degrees C. The growth of SE in eggs was lowest in the following order of laying: February, October, and June. SE grew preferably in albumen of cracked eggs than intact eggs.

Animals↗

PubMed2005

Salmonella and raw shell eggs: results of a cross-sectional study of contamination rates and egg safety practices in the United Kingdom catering sector in 2003.

This study was prompted by epidemiological investigations of the unusual number of Salmonella Enteritidis outbreaks associated with the use of eggs in catering premises in England and Wales during 2002. The aims of the study, performed between April and May 2003, were to establish the rate of Salmonella contamination in raw shell eggs from catering premises, investigate any correlation between the origin and type of eggs and the presence of particular serotypes or phage types (PTs) of Salmonella, and examine the use of raw shell eggs in catering premises in the United Kingdom. A total of 34,116 eggs (5,686 pooled samples of six eggs) were collected from 2,104 catering premises, most of which were eggs produced in the United Kingdom (88%). Salmonella was isolated from 17 pools (0.3%) of eggs. Of these, 15 were Salmonella Enteritidis, which were further characterized to PTs as follows: PT6 (0.1%), PT4 (0.07%), PT12 (0.04%), PT1 (0.04%), and PT14b (0.02%). Salmonella Livingstone and Salmonella Typhimurium definitive type 7 resistant to ampicillin, streptomycin, sulfonamides, and tetracycline were also isolated. The Salmonella contamination rate of eggs produced in the United Kingdom appears to have decreased significantly since 1995 and 1996. This trend is reflected in the decrease of Salmonella Enteritidis and, in particular, Salmonella Enteritidis PT4. The impact of the United Kingdom Food Standards Agency's advice on the use of eggs, issued in January 2003, is discussed.

Animals↗

PubMed2005

Destruction of Salmonella Senftenberg on the shells of intact eggs by thermoultrasonication.

The combined effect of ultrasonic waves and heat treatment applied simultaneously was evaluated on the survival of strains of Salmonella Senftenberg on shells of intact eggs. This combined process has a higher killing effect than heat treatment alone. The decimal reduction times (D-values) were decreased by 65.2 to 11.1% in the temperature range studied (57.8 to 67 degrees C). In contrast to the effect on Salmonella enterica serovar Enteritidis in a previous study, thermoultrasonication had no important advantage for elimination of Salmonella Senftenberg. However, because 52 degrees C is a nonlethal temperature for Salmonella Senftenberg, the conditions used for the elimination of Salmonella Enteritidis (52 degrees C for 12 min) in the previous study would be equivalent to ultrasonic treatment alone in the present study. This thermoultrasonication treatment may result in a 100-fold greater reduction of Salmonella Senftenberg than that achieved by common in-shell egg pasteurization (60 degrees C for 3.5 min).

Animals↗

PubMed1992

Is there lipid peroxidation induced malondialdehyde production during egg shell formation?

The marked increase observed in malondialdehyde concentration of the blood plasma and liver of laying hens during egg shell formation in a previous experiment (Mézes and Lencsés, 1985) were explained as a possible consequence of physiologically controlled lipid peroxidation. In this experiment, 54-week-old laying hens were treated intrauterinally with indomethacin (1.0 and 2.0 mg/kg body mass) after oviposition. Two other groups of hens were treated per os with excess amounts of vitamin E (100 and 200 mg/bird). The higher dose of indomethacin significantly decreased the PGF2 alpha production and malondialdehyde content of the sell gland, as well as the malondialdehyde concentration of the plasma. The excess amount of vitamin E had the same effect. The results suggest that during egg shell formation malondialdehyde is derived from prostanoid biosynthesis rather than from a free-radical initiated lipid peroxidative process. On the other hand, the excess amount of vitamin E inhibited prostaglandin biosynthesis as well as malondialdehyde production.

Animals↗

PubMed2006

Acid glycosidases in the isthmus of the hen oviduct and egg shell membranes.

Specific activities of seven acid glycosidases: beta-hexosaminidase, alpha- and beta-galactosidase, alpha- and beta-mannosidase, alpha-glucosidase and alpha-fucosidase were determined in various parts of the domestic hen oviduct (infundibulum, isthmus, shell gland and vagina). The activity of most enzymes was the highest in the isthmus. Multiple forms of all acid glycosidases from the isthmus were separated by strong anion exchange chromatography at pH 6.0. The isoelectric points of the isthmus forms of beta-hexosaminidase, beta-galactosidase and alpha- and beta-mannosidase were determined by chromatofocusing. For the first time the high beta-galactosidase activity was found in hen egg shell membranes.

Analysis of Variance↗

PubMedDate not supplied

Preincubation dipping of turkey hatching eggs. I. Effect of shell treatment on amount and variability of fluid intake.

Two techniques for egg-shell treatment were evaluated for their effects on the quantity and variability of the fluid absorbed by turkey hatching eggs subjected to the temperature-differential method of egg dipping. The use of pin or drill to pierce a uniform hole through the shell and membrane(s) on the large end of each egg caused a significant increase in the quantity of dip solution absorbed. Variability in fluid uptake by the eggs also was reduced significantly. Utilization of dilute acid to remove cuticle completely from the whole egg surface or partially from either end also had similar effects. The techniques described also permit and effective dipping procedure that does not require the preheating step.

Absorption↗