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PubMed2006

Salmonella enterica serotype Enteritidis and eggs: a national epidemic in the United States.

Beginning in the 1970s, the incidence of Salmonella enterica serotype Enteritidis (SE) infection and the number of related outbreaks in the United States has increased dramatically. By 1994, SE was the most commonly reported Salmonella serotype, with an incidence of >10 laboratory-confirmed infections per 100,000 population in the Northeast. Intensive epidemiologic and laboratory investigations identified shell eggs as the major vehicle for SE infection in humans, and that the eggs had been internally contaminated by transovarian transmission of SE in the laying hen. Three key interventions aimed at preventing the contamination and growth of SE in eggs have included farm-based programs to prevent SE from being introduced into egg-laying flocks, early and sustained refrigeration of shell eggs, and education of consumers and food workers about the risk of consuming raw or undercooked eggs. Since 1996, the incidence of SE infection in humans has decreased greatly, although many cases and outbreaks due to SE contaminated eggs continue to occur.

Animals↗
PubMed2000

The role of outbreaks in developing food safety policy: population based surveillance of salmonella outbreaks in Wales 1986-98.

In developing public policy on food safety, systematic identification and thorough investigation of all general outbreaks is necessary in order to avoid bias towards highly publicised outbreaks. In Wales, from 1986 to 1998, 87 general foodborne outbreaks of salmonellosis were identified. Most outbreaks occurred at functions or were associated with small catering outlets such as bakeries and sandwich bars. In 50 outbreaks, a vehicle of infection was confirmed microbiologically and/or epidemiologically. The most common food vehicles were those containing shell eggs. Salmonella enteritidis outbreaks were significantly more likely than outbreaks of other serotypes to be associated with vehicles containing shell eggs, suggesting that eggs were also the source of infection in many outbreaks. The routine use of analytical epidemiological studies to identify vehicles in outbreaks is recommended.

Disease Outbreaks↗
PubMed1998

Calcium metabolism in olive ridley turtle eggs during embryonic development.

Analyses of calcium, magnesium, sulphur, potassium and phosphorus content of the eggshell, yolk-albumen and embryos of olive ridley turtle, Lepidochelys olivacea, have been carried out at various stages of embryonic development. Calcium is the major inorganic constituent in the egg (shell and yolk-albumen) and embryos. Other elements are present either in trace or in minute trace amounts. The egg contents (yolk and albumen) provide only 40% of the embryonic calcium requirement of the hatchling. The remaining 60% is provided by the eggshell. The eggshell also undergoes a similar reduction in its calcium content from laying to hatching. Elements other than calcium present in the yolk-albumen are sufficient for normal embryonic development. The movement of calcium from the eggshell to the embryo starts at about the 40th day of development at 29.5 degrees C. Birds, turtles and crocodiles use their eggshell as the secondary source of embryonic calcium requirement. This dependence on the eggshell varies in different groups which is highest in birds and lowest in crocodiles.

Albumins↗
PubMed1990

Study on effects of feeding laying hens on separate mycotoxins (aflatoxins, patulin, or citrinin)-contaminated diets on the egg quality and tissue constituents.

Four groups (each of 8 laying hens plus one cock) were offered commercial laying mash contaminated with 100 ppb of aflatoxins, citrinin, patulin or uncontaminated (control) for 6 weeks. The mycotoxin-contaminated diets led to some significant changes in egg characteristics and composition such as ash and calcium contents of the egg shell. The noticeable changes including also the relative weights of adrenal glands. Blood profile reflected too alterations (P greater than 0.05) in urea content and activity of both glutamic oxaloacetic transaminase and alkaline phosphatase as well. The mycotoxins affected significantly moisture and fat contents of the red muscle and protein content, texture and percentage of lean meat in both types of muscles (red and white). Patulin toxicosis was responsible for the strongest alterations in moisture, fat and vitamin A contents of the laying hen's liver and for the lowest calcium content of egg shell besides the shape alteration of the eggs. Laying hens fed on aflatoxin-contaminated diet produced hatched chicks with higher weight (P less than or equal to 0.05) than those from the controls. Citrinin residues were 10 ppb in the fresh muscles and egg yolk and 6 ppb in egg white.

Aflatoxins↗
PubMed1975

[Studies on the hatching of miracidia of Dicrocoelium dendriticum (author's transl)].

The eggs of Dicrocoelium dendriticum were induced to open by solutions of formic acid and caproic acid (Table 1). The miracidia hatched in O2-free water after the eggs had been dried with N2 or in vacuum. The miracidia were able to live for 3 hours if water contained 20 mM NaCl, 10 mM KCl, and 1 mM CaCl2. Ca++-ions are obviously necessary for the mobility of miracidia. The experimental use of intestinal juice of the Roman snail Helix pomatia gave hatching results which were dependent on the absence of O2 (exposure to N2) and the presence of bacteria with a still unknown function. The dependence on pH seems to be indirect (Abb. 2). Studies on the permeabilities of the egg shell and the embryonic membrane ("vitelline membrane"), the evidence of an oligosaccharide (Abb. 3) liberated from the "spaltraum" (Abb. 1) during egg-opening, and the determination of the osmotic pressure of the hatching process (50% hatching in 1.2--14. Osmols sucrose/1000 ml H2O; Abb. 4) led to the following hypothesis of hatching mechanism: After the activation of the granular gland of the miracidium an enzyme is released into the extra-embryonic "spaltraum". A polysaccharide is digested to an oligosaccharide which cannot permeate the egg shell and the embryonic membrane. The rising osmotic pressure bursts off the operculum.

Animals↗
PubMed1987

The innermost chorionic layer of Drosophila. II. Three-dimensional structure determination of the 90 degrees crystal form by electron microscopy.

The innermost chorionic layer (ICL) within egg shells of Drosophila is composed of a family of related, thin three-dimensional crystals that form a continuous sheath encapsulating the egg shell lumen. Junctions formed by interdigitating lattices play a central role in the construction of this macroscopic assembly. The three-dimensional structure of a two-dimensional crystal isolated from the ICL, with a primitive lattice angle delta of 90 degrees, has been determined from a complete tilt series of a negatively contrasted specimen at a resolution of 25 A. Inspection of the three-dimensional transform after data merging revealed that the space group is c222 and this symmetry was employed to generate a three-dimensional structure. The basic structural unit of the ICL is an octamer, described formally as a tetramer of dimers with point group symmetry 222. There are two classes of dimer in the octamer designated alpha and beta. The chorin octamer is composed of two classes of bent dimers, which make intramolecular contacts at the top and bottom of the molecule. The alpha-dimers are curved outwards away from the crystallographic 2-fold axis, while the beta-dimers are curved towards the molecular center. In addition, lattice contacts are formed primarily by beta-chorin dimers at both the top and bottom surfaces of the unit cell. The molecular weight of a chorin octamer determined from the analysis is about 6 X 10(5). The conformation of the chorin octamer determined here suggests that permutations of a basic molecular mechanism may be adequate to explain both the observed lattice polymorphisms of the ICL and the formation of interplate junctions necessary for the assembly of the macroscopic sheath.

Animals↗
PubMed1985

[Number of intrauterine eggs in female Enterobius vermicularis by body length]

In order to correlate the number of eggs in female Enterobius vermicularis with their body length and to re-evaluate the number of eggs liberated by gravid females, a total of 203 worms were examined. Those females were removed from naturally infected orphans with mebendazole (100 mg) and had been fixed in 10 percent formalin(Cho et al., 1981). The decent ones which were selected under dissecting microscope were unbroken, neatly fixed females without contaminated eggs on their surface. The worms were measured by their body length, softened in 0.1N NaOH solution overnight, and teased by dissecting needles. And their number of shelled eggs was measured in a counting chamber made as described by Denham et al. (1971). The results were summarized as follows: The observed females, 4.10~9.90 mm long, began to have shelled eggs in uterus when body length was 5.50 mm or longer. The percentage of females with eggs in uterus was as follows by range of body length: 25 percent in 5.50~5.99 mm long, 53.3 percent in 6.00~6.49 mm long, 86.7 percent in 6.50~6.99 mm long, 95.2 percent in 7.00~7.49 mm long and 100 percent in 7.50 mm or longer. The mean and standard deviation of egg number were as follows by the length of females: 19+/-50 in 5.50~5.99 mm long, 734+/-1,597 in 6.00~6.49 mm long, 1,473+/-1,606 in 6.50-6.99 mm long, 1,530+/-2,055 in 7.00-7.49 mm long, 2,567+/-2,046 in 7.50-7.99 mm long, 5,598+/-2,470 in 8.00~8.49 mm long, 9,318+/-2,651 in 8.50~8.99 mm long, 10,678+/-2,892 in 9.00~9.49 mm long and 13,323+/-1,778 in 9.50~9.90 mm long. The numbers of uterine eggs showed greater individual variation when the female lengths were in range of 5.5~8.0 mm. When the female length was longer than 9.0 mm, the egg numbers were over 10,000 in majority, and showed lesser individual variations. Above results suggested that the egg production in female E. vermicularis began in 28-32 days after infection and that in early stages, the egg production varied by individual worms, but in gravid females longer than 9.0 mm at last deposited 10,000 to 16,000 eggs in their uterus with the least individual variations.

Journal Article↗
PubMed1980

Reproductive capacities of control mallard ducks (Anas platyrhynchos) during a one-generation reproduction study.

The Mallard duck (Anas Platyrhynchos) is the waterfowl model of choice for testing the reproductive impairment of pesticides and environmental contaminants. The literature contains numerous reports on the effects of pesticides on egg shell development for mallards, quail and other avian species. Limited control data for reproductive evaluation of pesticides can be found. This paper summarizes one generation reproduction results from 75 control female mallard ducks. One male and five female adult ducks were housed in clean pens with tap water and game bird breeder ration available ad libitum. The pre-egg laying cycle was ten weeks in duration. For the first eight weeks, the photoperiod was seven hours light per day, after which the photoperiod was increased to 17 hours to induce egg laying. Eggs were collected daly for eight weeks and incubated. Shell thickness was measured on one egg from each pen bi-weekly. The mean reproductive indices are as follows: Eggs Cracked/Eggs Laid - 2.18%; Viable 11-Day Embryos/Eggs Set-85.2%; Live 21-Day Embryos/Viable 11-Day Survivors-97.6%; Hatchlings/Live 21-Day Embryos-80.6%; and 14-Day Survivors/Hatchlings-89.3%. The mean egg shell thickness for 60 eggs is 0.378 millimeters.

Animals↗
PubMed1992

An investigation into an outbreak of Salmonella enteritidis phage-type 4 infection and the consumption of custard slices and trifles.

Epidemiological investigation into an outbreak of food poisoning in 17 patients caused by Salmonella enteritidis phage-type 4 demonstrated a highly significant association with consumption of custard, retailed in custard slices and trifles from a bakery on one day. The bakery had changed their recipe for custard 2 weeks earlier to include fresh shell eggs and had not followed earlier national advice on cooking eggs for human consumption. The case-control study supports earlier work associating Salmonella enteritidis phage-type 4 infection with consumption of uncooked or lightly cooked shell eggs.

Adult↗
PubMed1983

Survival of Salmonella typhimurium and Staphylococcus aureus in eggs cooked by different methods.

Shell eggs inoculated with Salmonella typhimurium and Staphylococcus aureus were cooked by recommended procedures for boiling, poaching, and frying. Except for poaching, the recommended procedures were inadequate in destroying the inoculum placed in the yolk. Boiling for 7 min was necessary for complete destruction of S. typhimurium and it took 12 min of boiling to destroy Staph. aureus. Cooking time-temperature relationship for complete kill depended on the cooking method with fried eggs. Four minutes and 70 C were needed for covered eggs, 3 min on each side at 64 C for turned over eggs, while cooking for 7.5 min at 64 C for sunnyside eggs was not sufficient for destruction of both of the test organisms. None of the test organisms could be recovered from omelets baked by the recommended procedure (86 C for 25 min). Scrambling for 1 min at 74 C was required for the complete destruction of S. typhimurium and 2 min at 78 C for Staph. aureus.

Eggs↗
PubMed1996

Introduction to egg pasteurization.

The science of microbiology is very young in comparison with the age of mankind. Related developments in the area of pasteurization have been made during the past 131 yr. This symposium reveals some recent advancements in pasteurization of shell eggs and egg products.

Animals↗
PubMed1979

Cadmium and the food chain: the effect of dietary cadmium on tissue composition in chicks and laying hens.

The cadmium content of body tissues and eggs was studied in broiler chicks and laying hens fed diets supplemented with 3, 12, and 48 microgram/g of cadmium. The 48 microgram/g level was selected as a slightly toxic level while the lower levels were felt to be representative of the amounts of cadmium which would occur in feedstuffs due to environmental contamination. All levels of cadmium resulted in increased cadmium content of kidney while only 12 and 48 microgram/g resulted in increases in the cadmium content of liver and muscle. As little as 3 microgram/g cadmium consistently increased the cadmium content of liver and muscle but this did not prove to be statistically significant. The transfer of dietary cadmium to the egg was found to be very low. Only the 48 microgram/g level resulted in an increase in cadmium content of the egg. This dietary treatment also resulted in reduced egg production and egg shell thickness.

Animal Feed↗
PubMed1998

Bacterial penetration into eggs washed with various chemicals and stored at different temperatures and times.

Eggs were washed with one of three commercial egg-washing chemicals, including a quaternary ammonium compound (QAC, pH 7.5), sodium carbonate (Na2CO3, pH 12), and sodium hypochlorite (NaOCl, 100 ppm, pH 7.5). One hundred fifty intact-shell eggs were washed at 43.3 degrees C with each of three chemicals. A control group was washed with tap water (H2O, pH 7.0). The washed eggs then were inoculated by immersion for 3 min into an aqueous suspension of Salmonella enteritidis at 10(4) colony-forming units/ml and dried for 30 min. The washed and inoculated eggs were stored at 4 degrees C or 23 degrees C, and bacterial penetration was checked at 0-, 7-, 14-, and 21-day intervals. The effects of egg-washing chemicals on microstructural changes of eggshell and postwash inoculation were examined using electron microscopy and conventional culture methods. Fifteen eggs were used in each sample. The results of microbial tests showed that both QAC and sodium hypochlorite treatments reduced bacterial penetration (less than 3.4% and 6.7%, respectively, on day 1 and 16.7% on day 21). The sodium carbonate treatment facilitated bacterial penetration during egg storage (less than 30% on day 1 and 76.7% on day 21). The eggs washed with tap water had a bacterial penetration rate of less than 6.7% on day 1 and 20% on day 21. As the storage intervals increased to 21 days, the bacterial penetration rate increased. Different storage temperatures (4 degrees C and 23 degrees C) did not cause a significant difference in bacterial penetration rates within 21-day interval. The results of electron microscopy showed that QAC and sodium hypochlorite at 100 ppm resulted in microbiologically clean eggs and did not destroy eggshell surfaces, which protected the eggs against future bacterial recontamination. The alkaline sodium carbonate produced visually clean eggs but altered the eggshell surface, which allowed bacterial recontamination.

Animals↗
PubMed1988

The emergence of grade A eggs as a major source of Salmonella enteritidis infections. New implications for the control of salmonellosis.

From 1976 to 1986, reported Salmonella enteritidis infections increased more than sixfold in the northeastern United States. From January 1985 to May 1987, sixty-five foodborne outbreaks of S enteritidis were reported in the Northeast that were associated with 2119 cases and 11 deaths. Twenty-seven (77%) of the 35 outbreaks with identified food vehicles were caused by Grade A shell eggs or foods that contained such eggs. National data from 1973 to 1984 showed that S enteritidis outbreaks (44%) were more frequently associated with egg-containing foods than were outbreaks of other Salmonella serotypes (15%). Reflecting the geographic distribution of human illness, cultures of bulk raw eggs from pasteurization plants in the Northeast more frequently yielded S enteritidis (10%) than did eggs from other regions of the United States (0%). The epidemic rise in S enteritidis infections due to Grade A shell eggs is unlike past problems of salmonellosis associated with cracked or soiled eggs and raises the possibility of trans-ovarian contamination of eggs with S enteritidis. New techniques may therefore be needed to control resurgent egg-associated salmonellosis in the United States.

Aged↗
PubMed1980

Autoradiographic localization of carbonic anhydrase in the developing chorioallantoic membrane.

Carbonic anhydrase was localized in the chorioallantoic membrane with labeled inhibitor autoradiography of 3H-acetazolamide at 11, 14 and 19 days of incubation. At 11 days carbonic anhydrase was present in low amounts only in the undifferentiated ectoderm cells. At 14 and 19 days, the enzyme was found in increased amounts in all three germ layers of the chorioallantois. In the chorionic ectoderm the villous cavity cells contained the highest level of carbonic anhydrase. This finding lends support to the theory of H+ production to solubilize the CaCO3 of the egg shell. Sinus covering cells showed a considerable lower concentration of the enzyme than did villous cavity cells. Carbonic anhydrase in these cells may be multifunctional, assisting in calcium transport, subserving HCO3- transport from egg shell to blood, and supporting gaseous exchange. In the allantoic endoderm carbonic anhydrase was found in granule-rich cells and might be involved in the transport of Na+ and Cl- ions from allantoic fluid into the blood. The enzyme in the undifferentiated endoderm cells may have a respiratory function. In the mesoderm carbonic anhydrase was detected in the endothelium and pericytes of blood vessels where it is interpreted to support respiratory function.

Allantois↗
PubMed1975

Exposure of eggs to ultrasound during incubation and its effect on hatchability and growth.

An experiment was undertaken to study the effect of exposing incubating embryos to short ultrasonic pulses across the intact egg shell. Three minute exposures to 2.25 MHz. pulses, average incident intensity equals 28.6 mW./cm.2, failed to show any effect on embryonic mutation, hatchability, sex ratio, or body weight. On the average the ultrasonic absorption of the egg shells ranged from 26 dB./mm. at 0.6 MHz. to 100 dB./mm. at 2.25 MHz. The transmitted power incident on the blastodisc, consisting mainly of spectrum components below 1.0 MHz., was estimated at congruent to 1% of the incident power.

Animals↗
PubMed1996

Line differences in resistance to Salmonella enteritidis PT4 infection.

1. Four groups of hens, each of a different line, were inoculated at peak of lay, per os in the crop with 1 ml of a suspension containing 10(9) cfu/ml Salmonella enteritidis PT4 (SE). The kinetics of SE contamination in the environment, egg shell and yolk were studied during the first 28 d post inoculation. On the day of slaughter, intestines, caeca, spleen, liver, ovary, oviduct and content were investigated for SE contamination. 2. The commercial egg-type line L2 was found to be the most susceptible to SE. It laid many SE-positive yolks (13.8%) and internal and faecal organs were frequently infected. 3. Certain lines are found to exhibit a degree of resistance to SE; the cause of which is unknown and might be attributed to major genes.

Abattoirs↗
PubMed1976

Calcium-binding protein and calcium absorption in the laying quail (Coturnix coturnix japonica).

A vitamin D3-dependent calcium-binding protein (CaBP) has been found in the intestinal mucosa of Japanese quail (Coturnix coturnix japonica). This protein is similar, if not identical to that of the chick (Gallus domesticus). A similar protein fraction appears also in uterine mucosa of laying quail. Both intestinal and uterine CaBP levels are higher in laying than in non-laying quails. Uterine CaBP was higher during egg shell formation than during uterine inactivity. The slight corresponding difference in the intestinal CaBP was not significant. Intestinal calcium absorption measured with 91Y as a reference substance was higher in birds during formation of egg shell than in those with inactive uteri. The possible role of CaBP in calcium translocation is discussed.

Animals↗