• Food Science of Animal Resources
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• v.33 no.2
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• pp.239-243
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• 2013

Salmonella Enteritidis is responsible for causing foodborne diseases upon consumption of egg products. While cases of S. Enteritidis isolation from eggs have been reported in other countries, no such cases have previously been reported in Korea. In this study, we report the first isolation and identification of S. Enteritidis from domestically distributed eggs in Korea. Eggs were collected from eight countrywide grocery stores during different seasons between 2011 and 2012. Egg contents and washing solution of egg shells were incubated in buffered peptone water, and the enriched broth was further enriched in tetrathionate broth and Rappaport-Vassiliadis. The secondary enriched broth was streaked on xylose lysine desoxycholate agar. The suspected colonies were confirmed to S. Enteritidis by a biochemical test, serotyping, and PCR test. Genetic relatedness among the isolates was analyzed using Diversilab Salmonella kit. Three strains of S. Enteritidis were isolated from egg contents and egg shells collected from grocery stores of the Eumseong-city in the fall of 2011. All three stains showed resistance to chloramphenicol, streptomycin, nalidixic acid, and ampicillin by the disk diffusion method. In addition, the isolates showed more than 99% DNA homology, indicating that they were presumably identical strains. Therefore, there is a requirement to monitor and control against S. Enteritidis from eggs in Korea.

• Korean Journal of Veterinary Service
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• v.28 no.3
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• pp.225-234
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• 2005

Egg has been considered as one of the most important food sources in both nutritionally and economically. However, because the hazards of egg flow chains' complexity from producers to consumers and the insufficiency of cold chain systems in Korea are still remained, preventive measures for egg safety should be established. This experiment was carried out to investigate the changes of egg qualify during storage in order to find out the proper storage condition and eggshell treatment. Eggs were stored at cold condition $(5^{\circ}C,\;relative\;humidity;\;RH:\;65\pm3\%)$ and room Condition $(1st: Sep\; 6\~Nov\; 15,\;2001,\; 10\~30^{\circ}C,\;RH\;41\~86\%,\;2nd;\; Dec\;13,\;2001\~Feb\;21,\;2002,\;4\~23^{\circ}C,\;RH\;36\~89\%)$ after eggshell treatment (unwashed, washed and coated egg) during'10 weeks and examined weight loss and interior quality periodically. Weight loss was in decreasing order room washed > room unwashed > cold washed > cold unwashed > room coated > cold coated egg. And, Haugh unit was decreasing order room washed > room unwashed > room coated > cold washed > cold unwashed > cold coated egg. Our findings show that both coated eggs and refrigeration reduces the rate of decline in Haugh units and egg weight. And, washed eggs had lower average Haugh units and a higher weight loss than any of the eggshell treatment in both storage conditions. Conclusively, for washing eggshell, 150 ppm of sodium hypochlorite, regular exchange and temperature control of water should be consistent and also eggs should be dried immediately after washing. Also, national guidelines for temperature and moisture of storage places, transportation and expiration data should be established to keep quality and weight loss of eggs. Storage temperature that is a critical factor in the quality and safety of eggs should be kept under 12'c and labelling of expiration date should be obligatory.

• Korean Journal of Agricultural Science
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• v.47 no.2
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• pp.283-290
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• 2020

In 2018, 647 thousand tons of eggs were produced and consumed. However, the issue of pesticides used for egg in 2017 made Korean consumers worry about the food safety of eggs, and the volume of egg consumption decreased. The Korean egg industry also has another problem due to an unclear and inefficient marketing structure at the farm level. This marketing situation of eggs at the farm level in Korea needs a large-scale restructuring of the market structure, including introducing an EPC (egg processing center). Especially, the introduction of an EPC has been discussed by government officers and specialists, but the social benefit of an EPC, which will be the driving point for approving an EPC, has not been measured yet. The purpose of this study was to measure the effect of introducing an EPC in Korea. Through an analysis using EDM (equilibrium displacement model), a few findings are presented. First, the introduction of an EPC may increase the transparency of price discovery and decrease the transaction cost. And thus, it results in a higher producer price, lower consumer price, and larger quantity at market equilibrium. Second, an EPC will improve the level of food safety of eggs, which can increase the satisfaction of domestic producers and consumers. Third, the introduction of an EPC may create new consumption of eggs. Based on these three effects, the new social benefits in monetary terms from the introduction of an EPC in Korea could be 23.9 - 35.2 billion won.

• Food Science and Preservation
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• v.16 no.5
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• pp.782-788
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• 2009

The genotoxicological safety of gamma-irradiated egg white and yolk was examined to ensure that required safety parameters were met, and in an effort to further apply gamma-irradiation for improvement of the hygienic qualities of eggs. Egg white and yolk were irradiated at 20 kGy, much higher than the legally approved dose (less than 5 kGy), and possible genotoxicity was evaluated using in vitro and in vivo tests. The SOS chromotest employing Escherichia coli PQ37, and a chromosomal aberration test in cultured Chinese hamster lung (CHL) cells, were performed in vitro with or without metabolic activation (S9). An in vivo micronucleus development test was conducted using mouse bone marrow cells. Negative results were obtained in the SOS chromotest. The incidence of chromosomal aberration in CHL cells and the frequency of micronuclear developmentin mouse bone marrow cells treated with irradiated samples were not significantly different from those of non-irradiated controls. Thus, it may be concluded that up to 20 kGy of gamma irradiation applied to egg white and yolk did not show any genotoxic effects under our experimental conditions.

• Journal of Food Hygiene and Safety
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• v.37 no.4
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• pp.207-215
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• 2022

The intensity of fishy odor in eggs, which differs depending on the poultry type and individual perception, can be due to many factors including trimethylamine (TMA) which has been identified as the main. Notably, riboflavin can increase the activity of flavin-containing monooxygenase 3, the enzyme responsible for converting TMA into odorless trimethylamine-N-oxide. This study aimed to analyze the TMA content in egg yolk, evaluate its contribution to fishy odor, and develop a method to prevent this undesired odor. Solid-phase microextraction-gas chromatography/mass spectrometry was used to detect and quantify volatile compounds in egg yolk from hens fed a standard TMA-rich diet and hens fed a riboflavin-supplemented diet. To compare the relative content of volatile substances between eggs, a correlation study was performed using an electronic nose. Higher concentration of TMA (1.06 ± 0.12 mg/kg) was detected in egg yolks obtained from hens fed a normal diet than those fed a riboflavin-supplemented diet. Overall, this study suggests that riboflavin affects the quantity and quality of volatile substances, including TMA, present in eggs and we expect these findings to improve the quality and reduce the fishy odor of eggs.

• Food Science of Animal Resources
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• v.38 no.2
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• pp.291-301
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• 2018

To shorten the production cycle of Zaodan, this study first pickled Zaodan by a novel technology - vacuum decompression technology. Vacuum decompression technology could reduce the pickling time of Zaodan from 20 wk to about 9 wk. The protein content, moisture and pH of the Zaodan egg white gradually decreased with a concomitant increase in salt during the pickling process. The total sulfhydryl group (SH) group content of the egg white proteins was increased to $2.43{\times}10^{-3}mol/L$ after being pickled for 30 d, whereas the content of disulphide bonds (SS) was reduced to $23.35{\times}10^{-3}mol/L$. The surface hydrophobicity was lowest after pickling for 30 d. In addition, great changes occurred in the secondary structure of the egg white proteins after pickling for 20 d. The disappearance of ovomucin was noticeable based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis.

• Journal of Food Hygiene and Safety
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• v.39 no.4
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• pp.353-355
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• 2024

Salmonella enterica subsp. enterica serovar Gallinarum biovar Gallinarum causes fowl typhoid in poultry. In this study, we isolated Salmonella from a Korean retail chicken shell egg and performed whole-genome sequencing, from which we identified one chromosome (4,659,977-bp) and two plasmids (plasmid_1: 87,506 bp and plasmid_2: 2,331 bp). The isolate serotype was confirmed to be Gallinarum, with a biovar type of Gallinarum, which was finally identified as Salmonella enterica subsp. enterica serovar Gallinarum biovar Gallinarum. Multilocus sequence typing confirmed that the isolate was that of sequence type 78. The antimicrobial resistance gene, aac(6')-laa, was identified on the chromosome, and 166 virulence genes were detected on the chromosome and plasmid_1.

• Development and Reproduction
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• v.17 no.1
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• pp.25-35
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• 2013

We investigated the effects of shell height on reproductive potential of the female Rapana venosa in three regions of different salinities (the coastal zone of the Gwangyang Bay (S-1); the upper reaches (S-3); lower reaches (S-2) of the Seomjin River). The number of egg capsules, egg capsule height, and fecundity associated with reproductive potential of larger female rapa whelks were higher than those of smaller individuals in all three regions. Correlation analyses showed that there is a significant positive correlation between egg capsule and female shell height. Mean of shell heights, egg capsule heights, the number of egg capsules in an egg mass, and fecundity in an egg capsule produced from female individuals inhabiting S-1 region were markedly higher than those inhabiting S-2 and S-3 regions. In particular, the fecundity of the rapa whelk increased with the salinity and shell height. Although large rapa whelks produced a large number of egg capsules at S-1 region, those at S-3 habitat laid less egg capsules with smaller size. If these rapa whelks were put into S-2 region, the number of egg capsules produced by a female at S-2 region was slightly larger than those produced by a female at S-3 region. This provides a clear evidence that the number of the egg capsules can be controlled by the salinity. In the coastal zone of the Gwangyang Bay and the upper reaches of Seomjin River, the fecundity of this species was estimated to be approximately 182,000-1,302,000 eggs/ind./yr.

• International Journal of Industrial Entomology and Biomaterials
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• v.15 no.1
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• pp.1-7
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• 2007

At present, multivoltine silkworm races reared five times per year involving huge manpower and rearing expenditure. Egg diapausing behavior is facultative in multivoltine and egg diapause was induced in selected multivoltine races by regulating temperature at $18^{\circ}C$, relative humidity 80% and photoperiod (6L:18D) in the late stage silkworm rearing. The maximum percentage of egg diapause induction was recorded in Rong Diazo, Diazo and MW13 showed 94%, 93% and 92% respectively, whereas the races A14DY and OS-616 showed minimum diapause induction 15% and 18% respectively. The diapause induced multivoltine eggs were preserved up to six months by cold preservation schedule normally adopted for bivoltine. After three and six months egg preservation, the diapause induced layings were released and observed for hatching percentage, all races showed above 82 % of hatching except the race AP12, which showed only 78 % of hatching. This methods reduce the crop cycle, gives strong safety backup and preventing the genetic erosion. This study helps formulating a new conservation method for multivoltine silkworm germplasm.

• Journal of the FoodService Safety
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• v.2 no.1
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• pp.30-35
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• 2021

This study was conducted to understand the perception and the usage pattern of egg dishes in university students. The questionnaires were collected from 200 university students residing in Seoul. The age group was 118 (59.0%) in 20s, 50 (25.0%) in 30s, and 32 (16.5%) in 40s and older. Also, 179 (89.5%) were undergraduate students and 21 (10.5%) were graduates. The result of food preferences in the overall survey was as follows: Meats and Poultry (4.46±1.03) > Seafoods (2.92±1.41) > Fruits (2.91±1.17) > Eggs (2.50±1.10) > Vegetables (2.21±1.17). The preference of foods using eggs as the main ingredient was as follows: Rolled egg (4.07±0.81) > Steamed egg (4.05±0.91) > Scrambled egg (3.83±1.03) > Rice omelet (3.77±1.03). The preference of foods using eggs as sub-ingredient was Egg in Ramyeon (4.11±1.08) > Fried egg over Bibimbob (3.87±0.91) > Sliced boiled egg in Naengmyeon (3.78±1.11). The preference of eggs as desserts was Egg tart (4.01±1.08) > Sponge cake (3.72±1.09) > Egg bread (3.63±1.13). The result of the frequency of eating eggs indicating that approximately two-thirds of university students consumed eggs more than 3 times a week. Although there was no significant difference, male students not only consumed eggs more frequently than female students, but also consumed a higher amount. In recent years, since one-person household in college students tends to increase, it is more important to save cooking time and food quality. Thus, the development and dissemination of various egg recipes should be prioritized for university students.