Consumption of Contaminated Eggs: A Public Health Concern

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Saif N. Al-Bahry Ibrahim Younis Mahmoud Salma K. Al-Musharafi James Rolf Paulson


The presence of pathogenic bacteria and fungi in food and the contamination of food with heavy metals and organic pollutants have become major global public health issues and economic concerns.  Although eggs are often thought of as perfect, naturally packaged sources of nutrition, the eggs of chickens, other fowl, and sea turtles are in fact among the most commonly contaminated foods worldwide.  The egg cuticle and eggshell are generally ineffective in preventing the entry of microbes and some chemicals. As a result of the overuse of antibiotics, pathogenic microorganisms that invade eggs are often found to be resistant to antimicrobial drugs.  In addition, due to heavy usage in agriculture and various industries, synthetic organic chemicals and heavy metals enter the environment and can find their way into food chains and eventually contaminate eggs.  In an effort to minimize these various types of contamination, regulations have been established to control the egg industry.  However, in some regions of the world enforcement is lax and compliance is poor.  The aim of this paper is to raise awareness of the need for rigorous enforcement of the rules, greater industry compliance with standards, increased monitoring, and further research on the public health issues.

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How to Cite
AL-BAHRY, Saif N. et al. Consumption of Contaminated Eggs: A Public Health Concern. Medical Research Archives, [S.l.], v. 2, n. 4, nov. 2015. ISSN 2375-1924. Available at: <>. Date accessed: 16 apr. 2024.
Eggs; contamination; microbes; organic pollutants; heavy metals; antibiotic resistance
Review Articles


[1] Al-Bahry SN. “Antibiotic resistance of Salmonella isolated from Muscat, Oman,” Pakistan Journal of Biological Sciences, vol. 2, no. 2 (1999): 523-528, url:
[2] Al-Bahry SN. “Plasmid profiles of antibiotic resistant Salmonella species isolated in Muscat, Oman,” Pakistan Journal of Biological Sciences, vol. 3, no. 2 (2000): 215-218, url:
[3] Al-Bahry SN, Al-Mashani BM, Elshafie AE, Pathare N, Al-Harthy AH. “Plasmid profile of antibiotic resistant Escherichia coli isolated from chicken intestines,” Journal of Alabama Academy of Sciences vol. 77, no. 3-4 (2006): 152-159.
[4] Al-Bahry SN, Elshafie AE, Al-Busaidi S, Al-Hinai JA, Al-Shidi, I. “Antibiotic resistant Salmonella spp. from human and non-human sources in Oman,” Eastern Mediterranean Health Journal, vol. 13, no. 1 (2007): 49-55, url:
[5] Al-Bahry SN, Mahmoud IY, Elshafie AE, Al-Harthy A, Al-Ghafri S, Al-Amri I, Alkindi AY. “Bacterial flora and antibiotic resistance from eggs of green turtles Chelonia mydas: an indication of polluted effluents,” Marine Pollution Bulletin, vol. 58, no. 5 (2009): 720-725, url:
[6] Al-Bahry SN, Mahmoud IY, Al-Belushi KI, Elshafie AE, Al-Harthy A, Bakheit CK. “Coastal sewage discharge and its impact on fish with reference to antibiotic resistant enteric bacteria and enteric pathogens as bio-indicators of pollution,” Chemosphere, vol. 77, no. 11 (2009): 1534-1539. url:
[7] Al-Bahry SN, Mahmoud IY, Al-Khaifi A, Elshafie AE, Al-Harthy, A. “Viability of multiple antibiotic resistant bacteria in distribution lines of treated sewage effluent used for irrigation,” Water Science & Technology, vol. 60, no. 11 (2009): 2939-2948.
[8] Al-Bahry SN, Mahmoud IY, Al-Zadjali M, Elshafie A, Al-Harthy A, Al-Alawi W. “Antibiotic resistant bacteria as bio-indicator of polluted effluent in the green turtles, Chelonia mydas in Oman,” Marine Environmental Research, vol. 71, no. 2 (2011): 139-144.
[9] Al-Bahry SN, Mahmoud IY, Al-Musharafi SK, Al-Ali MA. “Penetration of spoilage and food poisoning bacteria into fresh chicken egg: a public health concern,” Global Journal of Bioscience and Biotechnology (GJBB), vol. 1, no. 1 (2012): 33-39.
[10] Al-Bahry SN, Al-Zadjali MA, Mahmoud IY, Elshafie AE. “Biomonitoring marine habitats in reference to antibiotic resistant bacteria and ampicillin resistance determinants from oviductal fluid of the nesting green sea turtle, Chelonia mydas,” Chemosphere, vol. 87, no. 11 (2012): 1308-1315. url:
[11] Al-Bahry SN, Mahmoud IY, Al-Musharafi SK. “Antibiotic resistant bacteria used as bioindicators of environmental pollution produced by tertiary treated sewage effluent,” in Water Pollution XI, WIT Transactions on Ecology and the Environment vol. 164, C.A. Brebbia, Ed., WIT Press, Southampton, UK, 2012, pp. 313-321.
[12] Al-Bahry SN, Mahmoud IY, Al-Musharafi SK. “The overuse of tetracycline compounds in chickens and its impact on human health,” IPCBEE, vol. 50, no. 1 (2013): 21-25.
[13] Al-Bahry SN, Al-Hinai JA, Mahmoud IY, Al-Musharafi SK. “Opportunistic and microbial pathogens in municipal water distribution systems,” APCBEES Procedia, vol. 5 (2013): 339-343. url:
[14] Al-Bahry SN, Al-Mashani BM, Al-Ansari AS, Elshafie AE, Mahmoud IY. “Escherichia coli tetracycline efflux determinants in relation to tetracycline residues in chicken,” Asian Pacific Journal of Tropical Medicine, vol. 6, no. 9 (2013): 718–722. url:
[15] Al-Bahry SN, Mahmoud I, Al-Rawahi S, Paulson JR. “Egg contamination as an indicator of environmental health,” in Eggs: Nutrition, Consumption and Health. W. Segil and H. Zou, Eds., Nova Science Publishers, Inc. Hauppauge, New York, USA, 2013, pp. 1-24.
[16] Al-Bahry SN, Mahmoud IY, Al-Musharafi SK, Al-Gharaibi IS, Al-Harthy NK, Al-Zadjali HA. “Microbial and chemical pollution of water-wells relative to sewage effluents in Oman,” IAFOR Journal of Sustainability, Energy and the Environment (IJSEE), vol. 1, no. 1 (2014): 35-56. url:
[17] Al-Bahry SN, Mahmoud IY, Paulson JR, Al-Musharafi SK. “Antibiotic resistant bacteria in terrestrial and aquatic environments: a review,” International Arabic Journal of Antimicrobial Agents, vol. 4, no. 3 (2015): 1-11. url:
[18] Al-Lawati IJ, Al-Bahry SN, Ba-Omar T, Elshafie AE. “The use of SEM in studying infected chicken eggs by Salmonella typhimurium,” Microscopy and Microanalysis, vol. 9, suppl. 2 (2003): 1490-1491.
[19] Al-Musharafi SK. “Analysis of heavy metal in eggshells of green turtles, Chelonia mydas, by scanning electron microscopy and x-ray microanalysis,” in Biotechnology and Conservation of Species from Arid Regions, S.A. Farooq, R.M.M. Abed and S. Baqir, Eds, Nova Science Publishers, Inc., Hauppauge, New York, USA, 2014, pp. 137-144.
[20] Al-Musharafi SK, Mahmoud IY, Al-Bahry SN. “Heavy metal contamination from treated sewage effluents,” in Water Pollution XI, WIT Transactions on Ecology and the Environment vol. 164, C.A. Brebbia, Ed., WIT Press, Southampton, UK, 2012, pp. 381-389.
[21] Al-Musharafi SK, Mahmoud IY, Al-Bahry SN. “Heavy metal pollution from treated sewage effluent,” APCBEES Procedia, vol. 5 (2013): 344 – 348. url:
[22] Al-Musharafi SK, Mahmoud IY, Al-Bahry SN. “Contamination of marine fish by heavy metals from coastal sewage treated effluent runoff,” The Third Asian Conference on Sustainability, Energy and the Environment, acsee2013, The International Academic Forum (IAFOR), Osaka, Japan, 2013, pp. 100-107. url:
[23] Al-Musharafi SK, Mahmoud IY, Al-Bahry SN. “Environmental contamination by industrial effluents and sludge relative to heavy metals,” Journal of Geoscience and Environment Protection, vol. 2, no. 2 (2014): 14-18. url:
[24] Al-Musharafi SK, Mahmoud IY, Al-Bahry SN., “Environmental hazards and pollution from liquid waste lagoons,” IPCBEE, vol. 69, no. 1 (2014): 1-5.
[25] Al-Rawahy SH, Al Kindi AY, Elshafie A, Mahmoud IY, Al-Bahry SN, Al-Siyabi SS, Mansour MH, Al-Kiyumi AA. “Accumulation of metals in the egg yolk and liver of hatchling of green turtles Chelonia mydas at Ras Al Hadd, Sultanate of Oman,” ANSI: Journal of Biological Sciences, vol. 7, no. 6 (2007): 925-930. url:
[26] Allen HK, Donato J, Wang HH, Cloud-Hansen KA, Davies J, Handelsman J. “Call of the wild: antibiotic resistance genes in natural environments,” Nature Reviews Microbiology, vol. 8, no. 4 (2010): 251-259. url:
[27] American Egg Board,, 2015. Accessed 15 March 2015.
[28] Arias JL, Fernandez MS. “Role of extracellular matrix molecules in shell formation and structure,” World’s Poultry Science Journal, vol. 57, no. 3 (2001): 349-357.
[29] Baars AJ, Bakker MI, Baumann RA, Boon PE, Freijer JI, Hoogenboom LA, Hoogerbrugge R, van Klaveren JD, Liem AK, Traag WA, de Vries J. “Dioxins, dioxin-like PCBs and non-dioxin-like PCBs in foodstuffs: Occurrence and dietary intake in The Netherlands,” Toxicology Letters, vol. 151, no. 1 (2004): 51–61. url:
[30] Baker JR, Balch DA. “A study of the organic material of the hen’s-egg shell,” Biochemical Journal, vol. 82, no. 2 (1962): 352-361. url:
[31] Baker RC, Hogarty S, Poon W, Vadehra DV. “Survival of Salmonella typhimurium and Staphylococcus aureus in eggs cooked by different methods,” Poultry Science, vol. 62, no. 7 (1983): 1211-1216. url:
[32] Bargellini A, Marchesi I, Rizzi L, Cauteruccio L, Masironi R, Simioli M, Borella P. “Selenium interactions with essential and toxic elements in egg yolk from commercial and fortified eggs,” Journal of Trace Elements in Medicine and Biology, vol. 22, no. 3 (2008): 234–241. url:
[33] Barrow PA. “Experimental infection of chickens with Salmonella enteritidis,” Avian Pathology, vol. 20, no. 2 (1991): 145-153. url:
[34] Bellairs R, Boyde A. “Scanning Electron Microscopy of the shell membranes of the hen’s egg,” Cell and Tissue Research, vol. 96, no. 2 (1969): 237-249.
[35] Berger-Bachi B. “Resistance mechanisms of gram-positive bacteria,” International Journal of Medical Microbiology, vol. 292, no. 1 (2002): 27-35. url:
[36] Berrang ME, Frank JF, Buhr JR, Bailey SJ, Cox NA. “Egg shell membrane structure and penetration by Salmonella typhimurium,” Journal of Food Protection, vol. 62, no. 1 (1999): 73-76.
[37] Błądek T, Posyniak A, Gajda A, Gbylik M, Żmudzki J. “Multi-class procedure for analysis of antibacterial compounds in eggs by liquid chromatography-tandem mass spectrometry,” Bull. Vet. Inst. Pulawy, vol. 56, no. 3 (2012): 321-327.
[38] Blankenship LC, Davis CE, Magner GJ. “Cooking methods for elimination of Salmonella typhimurium experimental surface contaminant from rare dry-roasted beef roasts,” Journal of Food Science, vol. 45, no. 2 (1980): 270-273.
[39] Blumenthal D. “Salmonella enteritidis; from the chicken to the egg,” FDA Consumer, vol. 24, no. 3 (1990): 7-11.
[40] Board R, Clay C, Lock J, Dolman J. “The egg: a compartmentalized, aseptically packaged food,” in Microbiology of the Avian Egg, R.G. Board and R. Fuller, Eds, Chapman and Hall, London, 1994, pp. 43-61.
[41] Borland ED. “Salmonella infection in poultry,”. Veterinary Record, vol. 97, no. 21 (1975): 406-408.
[42] Burger J, Gochfeld M. “Cadmium and lead in common terns (Aves: Sterna hirundo): relationship between levels in parents and eggs,” Environmental Monitoring and Assessment, vol. 16, no. 3 (1991): 253-258.
[43] Burjaq SZ, Shehabi AA. “Fresh leafy green vegetables associated with multidrug resistant E. coli,” The International Arabic Journal of Antimicrobial Agents, vol. 3, no. 2 (2013): 1-7. url:
[44] Burley RW, Vadehra DV. The avian egg: Chemistry and Biology, John Wiley and Sons, NewYork, 1989.
[45] Cabello FC. “Heavy use of prophylactic antibiotics in aquaculture: A growing problem for human and animal health and for the environment,” Environmental Microbiology, vol. 8, no. 7 (2006): 1137-1144. url:
[46] Cason J, Bailey J, Cox N. “Location of Salmonella typhimurium during incubation and hatching of inoculated eggs,” Poultry Science, vol. 72, no. 11 (1993): 2064-2068. url:

[47] Catalano CR, Knabel SJ. “Destruction of Salmonella enteritidis by high pH and rapid chilling during simulated commercial egg processing,” Journal of Food Protection, vol. 57, no. 7 (1994): 592-595.

[48] Chen J, Clarke RC, Griffiths MW. “Use of luminescent strains of Salmonella enteritidis to monitor contamination and survival in eggs,” Journal of Food Protection, vol. 59, no. 9 (1996): 915-921.
[49] Chopra I, Roberts M. “Tetracycline antibiotics: mode of action, applications, molecular biology, and epidemiology of bacterial resistance,” Microbiology and Molecular Biology Reviews, vol. 65, no. 2 (2001): 232-260.
[50] Darwish WS, Eldaly EA, El-Abbasy MT, Ikenaka Y, Nakayama S, Ishizuka M. “Antibiotic residues in food: the African scenario,” Japanese Journal of Veterinary Research, vol. 61, suppl. (2013): S13-S22. url:
[51] Davidson CM, Witty JK. “Fate of Salmonella in vacuum–packaged ground meat during storage and subsequent cooking,” Canadian Institute of Food Science and Technology Journal, vol. 10, no. 3 (1997): 223-225.
[52] Demirulus H. “The heavy metal content in chicken eggs consumed in Van Lake territory,” Ekoloji, vol. 22, no. 86 (2013): 19-25.
[53] De Reu K, Grijspeerdt K, Messens W, Heyndrickx M, Uyttendaelle M, Debevere J, Herman L. “Eggshell factors influencing eggshell penetration and whole egg contamination by different bacteria, including Salmonella enteritidis,” International Journal of Food Microbiology, vol. 112, no. 3 (2006): 253–260.
[54] Donoghue DJ. “Antibiotic residues in poultry tissues and eggs: human health concerns?” Poultry Science, vol. 82, no. 4 (2003): 618-621. url:
[55] Doyle ME, Mazzotta AS. “Review of studies on the thermal resistance of Salmonellae,” Journal of Food Protection, vol. 63, no. 6 (2000): 779-795.
[56] ECHM (Environmental Chemistry and Hazardous Materials), “Periodic table of elements,” Accessed 15 March, 2015.
[57] Eckert KL, Eckert SA. “Embryo mortality and hatch success in in situ and translocated leatherback sea turtle (Dermochelys coriacea) eggs,” Biological Conservation, vol. 53, no. 1 (1990): 37-46.
[58] Edwards JW, Edyvane KS, Boxall VA, Hamann M, Soole KL. 2001. “Metal levels in Seston and marine fish flesh near industrial and metropolitan centers in South Australia,” Marine Pollution Bulletin, vol. 42, no. 5 (2001): 389-396. url:
[59] Eljarrat E, Monjonell A, Caixach J, Rivera J. “Toxic potency of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and polychlorinated biphenyls in food samples from Catalonia (Spain),” Journal of Agricultural and Food Chemistry, vol. 50, no. 5 (2002): 1161–1167. url:
[60] Elshafie AE, Ba-Omar TA, Al-Bahry SN, Mahmoud IY, Alkindi AY, Alamri I. “Localization of fungal hyphae in the eggshells of the green sea turtle, Chelonia mydas from Ras Al-Hadd Reserve, Oman,” Microscopy and Microanalysis, vol. 10, suppl. 2 (2004): 1536-1537.
[61] Elshafie AE, Al-Bahry SN, Al-Kindi AY, Ba-Omar T, Mahmoud IY. “Mycoflora and aflatoxins in soil, eggshells, and failed eggs of Chelonia mydas at Ras Al-Jinz, Oman,” Chelonian Conservation and Biology, vol. 6, no. 2 (2007): 267-270.
[62] Fathi MM, Afifi YK, El-Safty SA. “Ultrastructural diversity of eggshell quality in some Egyptian local breeds of chicken,” Egyptian Poultry Science, vol. 30, no. 3 (2010): 813-827. url:
[63] Focant JF, Eppe G, Pirard C, Massart AC, André JE, De Pauw E. “Levels and congener distributions of PCDDs, PCDFs and non-ortho PCBs in Belgian foodstuffs: Assessment of dietary intake,” Chemosphere, vol. 48, no. 2 (2002): 167–179. url:
[64] Gallani B, Verstraete F, Boix A, Von Holst C, Anklam E. “Levels of dioxins and dioxin-like PCBs in food and feed in Europe,” Organohalogen Compounds, vol. 66 (2004): 1893–1900.
[65] Gantois I, Ducatelle R, Pasmans F, Haesebrouck F, Gast R, Humphrey TJ, Van Immerseel F. “Mechanisms of egg contamination by Salmonella enteritidis,” FEMS Microbiology Reviews, vol. 33, no. 4 (2009): 718-738. url:
[66] Gast RK. “Understanding Salmonella enteritidis in laying chickens: the contributions of experimental infections,” International Journal of Food Microbiology, vol. 21, no. 1-2 (1994): 107–116.
[67] Gast RK, Holt PS. “Influence of the level and location of contamination on the multiplication of Salmonella enteritidis at different storage temperatures in experimentally inoculated eggs,” Poultry Science, vol. 79, no. 4 (2000): 559-563. url:
[68] Graves RC, MacLaury DW. “The effects of temperature, vapor pressure and absolute humidity on bacterial contamination of shell eggs,” Poultry Science, vol. 41, no. 4 (1962): 1219-1225. url:
[69] Grijspeerdt K. “Modelling the penetration and growth of bacteria in eggs,” Food Control, vol. 12, no. 1 (2001): 7-11. url:
[70] Hamm S, Grümping R, Schwietering J. “Levels of polychlorinated dibenzo(p)dioxins, dibenzofurans and dioxin-like PCBs in milk, milk products and eggs from West European countries,” 25th International Symposium on Halogenated Environmental Organic Pollutants, Toronto, Canada, 2005, pp. 1406–1408.
[71] Han FX, Banin A, Kingery WL, Triplet GB, Zhou LX, Zheng SJ, Ding WX. “New approach to studies of heavy metal redistribution in soil,” Advances in Environmental Research, vol. 8, no. 1 (2003): 113- 120. url:
[72] He ZL, Yang XE, Stoffella PJ. “Trace elements in agroecosystems and impacts on the environment,” Journal of Trace Elements in Medicine and Biology, vol. 19, no. 3 (2005): 125-140. url:
[73] Humphrey T. “Salmonella enteritidis PT4 infection in laying hens and consequences for egg contamination,” in Quality of Poultry Products. 2, Eggs and Egg Products: Proceedings of the 4th European Symposium on the Quality of Eggs and Egg Products, Doorwerth, Mary 12-17, 1991, A. Oosterwoud and A.W. de Vrie, Eds., Speldenholt Centre for Poultry Research and Information Services, Beekbergen, 1991, pp. 9-17.
[74] Humphrey TJ, Whitehead A. “Egg age and the growth of Salmonella enteritidis PT4 in egg contents,” Epidemiology and Infection, vol. 111, no. 2 (1993): 209-219. url:
[75] Humphrey TJ, Greenwood M, Gilbert RG, Rowe B, Chapman PA. “The survival of salmonellas in shell eggs cooked under simulated domestic conditions,” Epidemiology and Infection, vol. 103, no. 1 (1989): 35-45. url:
[76] Indar L, Baccus-Taylor G, Commissiong E, Prabhakar P, Reid H. “Salmonellosis in Trinidad: Evidence for transovarian transmission of Salmonella in farm eggs,” West Indian Medical Journal, vol. 47, no. 2 (1998): 50-53.
[77] Javed T, Hameed A, Siddique M. “Egg shell penetration tendency of different Salmonella Serotypes by attached ring color method.” Acta Microbiologica Polonica, vol. 43, no. 1 (1994): 67-72.
[78] Kenny C. “FDA inaction on antibiotics is making the world deadlier,” Bloomberg Businessweek,, 13 Dec. 2013.
[79] Khan S, Martin M, Bartsch H, Rahimtula, AD, “Perturbation of liver microsomal calcium homeostasis by ochratoxin A,” Biochemical Pharmacology, vol. 38, no. 1 (1989): 67-72.
[80] Kim CJ, Emery DA, Rinke H, Nagaraja KV, Halvorson DA. “Effect of time and temperature on growth of Salmonella enteritidis in experimentally inoculated eggs,” Avian Diseases, vol. 33, no. 4 (1989): 735-742.
[81] Kojadinovic J, Potier M, Le Corre M, Cosson RP, Bustamante P. “Bioaccumulation of trace elements in pelagic fish from the Western Indian Ocean,” Environmental Pollution, vol. 146, no. 2 (2007): 548-566. url:
[82] Kümmerer K. “Antibiotics in the aquatic environment. A review. Part I.” Chemosphere, vol. 75, no. 4 (2009): 417–434. url:
[83] Kümmerer K. “Antibiotics in the aquatic environment. A review. Part II.” Chemosphere, vol. 75, no. 4 (2009): 435–441. url:
[84] Limpus CJ, Reed P, Miller JD. “Islands and turtles: the influence of choice of nesting beach on sex ratio,” in Proceedings of the Inaugural Great Barrier Reef Conference, Townsville, Queensland, 28 August-2 September 1983, J.T. Baker, R.M. Carter, P.W. Sammarco and K.P. Stark, Eds., James Cook University Press, Townsville, Queensland, Australia, 1983, pp. 397-402.
[85] Mahmoud IY, Al-Bahry SN, Al-Musharafi SK. “Fresh water habitat pollution by treated sewage effluent in relation to multiple-antibiotic-resistant bacteria,” APCBEES Procedia, vol. 5 (2013): 363 – 367. url:
[86] Masshoff W, Stolpmann H. “Licht- und electronenmikroskopische Untersuchungen an der Schalenhaut und Kalkschale des Huhnereies,” Zeitschrift für Zellforschung, vol. 55, no. 6 (1961): 818-832.
[87] Messens W, Grijspeerdt K, Herman L. “Eggshell penetration by Salmonella: a review,” World’s Poultry Science Journal, vol. 61, no. 1 (2005): 71-82.
[88] Miyamoto T, Horie T, Baba E, Sassai K, Fukata T, Arakawa A. “Salmonella penetration through eggshell associated with freshness of laid eggs and refrigeration,” Journal of Food Protection, vol. 61, no. 3 (1998): 350-353
[89] Mo CL, Salas I, Caballero M. “Are fungi and bacteria responsible for olive ridley’s egg loss?” in Proceedings of the 10th Annual Workshop on Sea Turtle Biology and Conservation, 20-24 February 1990, Hilton Head Island, South Carolina, T.H. Richardson, J.I. Richardson and M. Donnelly, Eds., NOAA Tech. Mem. NMFS-SEFSC-278, 1990, pp. 249–252.
[90] Møller-Stray J, Eriksen HM, Bruheim T, Kapperud G, Lindstedt BA, Skeie Å, Sunde M, Urdahl AM, Øygard B, Vold L. “Two outbreaks of diarrhoea in nurseries in Norway after farm visits, April to May 2009”, Eurosurveillance, vol. 17, no. 47 (2012): 1-7. url:
[91] Moss MO. “Mycotoxin review – 1. Aspergillus and Penicillium,” Mycologist, vol. 16, no. 3 (2002): 116-119. url:
[92] Nascimento V, Cranstoun S, Solomon S. “Relationship between shell structure and movement of Salmonella enteritidis across the eggshell wall,” British Poultry Science, vol. 33, no. 1 (1992): 37-48.
[93] Padron M. “Salmonella typhimurium penetration through the eggshell of hatching eggs,” Avian Diseases, vol. 34, no. 2 (1990): 463-465
[94] Peters A, Verhoeven KJF, Strijbosch H. “Hatching and emergence in the Turkish Mediterranean loggerhead turtle, Carretta carretta: natural causes for egg and hatching failure,” Herpetologica, vol. 50, no. 3 (1994): 369-373. url:
[95] Phillott AD. “Pisonia grandis does not appear to harbour fungi known to invade sea turtle nests at Heron Island, Eastern Australia,” Transactions of the Royal Society of South Australia, vol. 125, no. 1 (2001): 69-70.
[96] Phillott AD, Parmenter CJ. “The ultrastructure of sea turtle eggshell does not contribute to interspecies variation in fungal invasion of the egg,” Canadian Journal of Zoology, vol. 84, no. 9 (2006): 1339-1344. url:
[97] Phillott AD, Parmenter CJ, Limpus CJ. “Mycoflora identified from failed green (Chelonia mydas) and loggerhead (Carretta carretta) sea turtle eggs at Heron Island, Australia,” Chelonian Conservation and Biology, vol. 4, no. 1 (2001): 170-172.
[98] Pruden A, Arabi M, Storteboom HN. “Correlation between upstream human activities and riverine antibiotic resistance genes,” Environmental Science & Technology, vol. 46, no. 21 (2012): 11541-11549. url:
[99] Radu-Rusu CB, Pop IM, Albu A, Bologa M, Radu-Rusu RM. “Transferability of certain heavy metals from hens feed to table eggs laid within different rearing systems,” Lucrări Ştiinţifice-Seria Zootehnie, vol. 59, no. 18 (2013): 218-222. url:
[100] Ritter L, Solomon KR, Forget J, Stemeroff M, O'Leary C. “Persistent organic pollutants,” United Nations Environment Programme (UNEP), 2007, url: Accessed March 2015.
[101] Ritz M, Freulet M, Orange N, Federighi M. “Effects of high hydrostatic pressure on membrane proteins of Salmonella typhimurium,” International Journal of Food Microbiology, vol. 55, no. 1-3 (2000): 115-119. url:
[102] Rupley JA. “The binding and cleavage by lysozyme of N-acetylglucosamine oligosaccharides,” Proceedings of the Royal Society B, vol. 167, no. 1009 (1967): 416-428.
[103] Shahidul I, Tanaka M. “Impacts of pollution on coastal and marine ecosystems including coastal and marine fisheries and approach for management: a review and synthesis,” Marine Pollution Bulletin, vol. 48, no. 7-8 (2004): 624-649. url:
[104] Shalinsky EI. “The ultrastructure of the shell and shell membrane of chicken eggs,” 6th International Congress on Electron Microscopy (Japan), 1966, p. 579.
[105] Simkiss K. Calcium in reproductive physiology: a comparative study of vertebrates, Chapman and Hall, London, 1967.
[106] Solomon SE. Egg and eggshell quality, Iowa State University Press, Ames, Iowa USA, 1997.

[107] Solomon SE, Baird T. “The effect of fungal penetration on the eggshell of the green turtle,” Proceedings of the Seventh European World Congress on Electron Microscopy, The Hague, the Netherlands, 24-29 August, 1980, P. Brederoo, Ed., vol. 2, Seventh European Congress on Electron Microscopy Foundation, Leiden, 1980, pp. 434-435.

[108] Solomon SE, Tippett R. “The intra-clutch localisation of fungal hyphae in the egg shells of the leatherback turtle Dermochelys coriacea,” Animal Technology, vol. 38, no. 2 (1987): 73-79.
[109] Sørensen PB, Vorkamp K, Thomsen M, Falk K, Møller S. Persistent organic pollutants (POPs) in the Greenland environment – Long-term temporal changes and effects on eggs of a bird of prey, National Environmental Research Institute. Ministry of the Environment, Denmark, 2004. url:
[110] Suzuki S, Hoa PTP. “Distribution of quinolines, sulfonamides, tetracyclines in the aquatic environment and antibiotic resistance in Indochina,” Frontiers in Microbiology, vol. 3, no. 1 (2012): 1-8. url:
[111] Tan CK, Chen TW, Chan HL, Ng LS. “A scanning and transmission electron microscopic study of the membranes of chicken egg,” Histology and Histopathology, vol. 7, no. 3 (1992): 339-345. url:

[112] Tyler C. “Avian eggshells: their structure and characteristics,” in International Review of General and Experimental Zoology, W.J.L. Felts and R.J. Harrison, Eds., vol. 4, Academic Press, New York, 1969, pp. 81-130.
[113] Van Overmeire I, Pussemier L, Hanot V, De Temmerman L, Hoenig M, Goeyens I. “Chemical contamination of free-range eggs from Belgium,” Food Additives and Contaminants, vol. 23, no. 11 (2006): 1109–1122.
[114] Wang H, Slavik MF. “Bacterial penetration into eggs washed with various chemicals and stored at different temperatures and times,” Journal of Food Protection, vol. 61, no. 3 (1998): 276-279.
[115] WHO (World Health Organization), Antimicrobial resistance: global report on surveillance, World Health Organization. Geneva, Switzerland, 2014. url:
[116] Yang HM, Wang ZY, Lu J. “Study on the relationship between eggshell colors and egg quality as well as shell ultrastructure in Yangzhou chicken,” African Journal of Biotechnology, vol. 8, no. 12 (2009): 2898-2902. url:
[117] Yang SE, Yu RC, Chou CC. “Influence of holding temperature on the growth and survival of Salmonella spp. and Staphylococcus aureus and the production of staphylococcal enterotoxin in egg products,” International Journal of Food Microbiology, vol. 63, no. 1-2 (2001): 99-107. url:
[118] Yildiz N, Yener G. “Dating of the sediment accumulation rate, radioactive and heavy metal pollution in the Van Lake.” Ekoloji, vol. 19, no. 87 (2010): 80-87.
[119] Zhou J, Wang S, Nie F, Feng L, Zhu G, Jiang L. “Elaborate architecture of the hierarchical hen’s eggshell.” Nano Research, vol. 4, no. 2 (2011): 171–179.