Effects of egg yolk powder addition to the flour dough on the lipid oxidation development during frying

Effects of egg yolk powder added to the dough on the oxidation of frying oil and lipid of fried products were studied. Flour dough containing egg yolk at 0, 3.53, 6.73, and 9.66/100 g was fried in 180 °C sunflower oil for 1.5 min, and 55 fryings were performed. Lipid damage was determined by free fatty acids (FFA), conjugated dienoic acids (CDA), and polar compounds contents, and p-anisidine values (PAV). Phospholipid (PL) classes were determined by high performance liquid chromatography. PL was not detected in frying oil and fried products without egg yolk, while the first batch of fried products added with egg yolk at 3.53, 6.73, and 9.66 in 100 g of the dough contained total PL at 3.73, 7.93, and 8.98 mg/g, respectively. Contents of PL classes tended to increase in the products fried in the oil performing more fryings. As the number of fryings of oil increased, FFA, CDA, and polar compounds contents and PAV of frying oil increased. Addition of egg yolk to the dough significantly decreased CDA and polar compounds contents and PAV of frying oil, but it increased FFA values. Lipid of fried products showed the same tendency in CDA contents and PAV. The results clearly indicate that egg yolk powder improved the oxidative stability of frying oil during frying, possibly due to PL.     

Nutritional composition of novel nutraceutical egg products developed with omega-3-rich oils

The ω-3 fatty acids (ω-3 FAs)-fortified eggs are typically developed through alteration of hen feed. The present study aimed at creating ω-3 FAs-fortified egg products via processing. Novel, nutritionally-enhanced egg products were developed by substituting cholesterol-containing yolk with ω-3 FAs-rich flaxseed, menhaden, algae, or krill oil. Experimental egg products (egg whites, ω-3 oils, and annatto), whole egg, and liquid egg product (Egg Beaters™) were microwave-cooked, analyzed, and compared. Protein, fat, and moisture contents of experimental egg products matched (P > 0.05) whole egg. Cholesterol was the highest (P < 0.05) in whole egg (1.35 g/100 g, dry weight basis); while it ranged 0.01-0.24 g/100 g (dry weight basis) in experimental egg products. On a per egg basis, one whole egg contained 216 mg; while experimental egg products ranged 1-38 mg. The total ω-3 FAs content was the lowest (P < 0.05) in whole egg (5.9% of total FAs) and the highest (P < 0.05) in experimental egg products developed with krill oil (46.5%), followed by flax (43.1%), algae (DHASCO-42.5% and DHAS-39.5%), and menhaden oil (27.6%). The essential amino acid (EAA) content of experimental egg products was similar (P > 0.05) to whole egg except methionine, phenylalanine, and valine were generally greater in experimental egg products. Experimental egg products also had similar (P > 0.05) content of non-EAA to whole egg except alanine and glutamic acid were higher (P < 0.05); while arginine and cysteine were generally lower and higher in experimental egg products, respectively. However, total EAA, total non-EAA, and the ratio of total EAA to total AA were similar (P > 0.05) between experimental egg products and whole egg. Whole egg contained more (P < 0.05) Ca, P, and Fe, but less Mg than experimental egg products.     

保健酱香软包装卤鸡蛋的研制

以土鸡蛋为主料,研究了加工具有保健作用的酱香型软包装卤鸡蛋食品的工艺条件和产品配方.确定最佳工艺技术是:压力/温度为0.15MPa/126℃,配方Ⅲ,卤制时间480rain,蛋料重量比1∶1.5.最优卤料液配方是Ⅲ:水500g,酱油100g,复合高倍甜味剂0.12g,味精1.0g,鸡精0.5g,复合香辛料1.2g.成品外表呈棕褐色,质地坚韧,酱香浓郁,具有一定的保健作用.     

Effect of gamma radiation and cold storage on chemical and organoleptic properties and microbiological status of liquid egg white and yolk

This investigation aims to establish a feasible radiation dose for treating liquid egg white (LEW) and yolk (LEY) at room temperature to improve their microbial safety. Samples of LEW and LEY were subjected to gamma irradiation doses of 0,1,2,3 and 4 kGy at room temperature followed by storage at 4 ± 1 °C. Then the effects of irradiation and cold storage on proximate composition, pH, soluble protein and free sulfhydryl content (SH) were determined for LEW and LEY in addition to the contents of total carotenoids in LEY. Moreover, free fatty acids (FFA) and peroxide value (PV) were determined for lipids of LEY.The microbial safety of LEW and LEY was established during storage throughout the enumeration of the total plate count, enterobacteriaceae, Staphylococcus aureus as well as the detection of Salmonella. The effects of irradiation at 3 kGy dose, which was enough for improving the microbial safety of samples, on amino acid composition of LEW and LEY and fatty acid profiles of LEY lipids were studied. In addition, sensory evaluation was carried out for liquid and scrambled egg white and egg yolk samples. The results showed that gamma irradiation and refrigerated storage had no significant effects on proximate composition and pH of liquid egg samples, while significantly decreased the contents of total carotenoids in LEY samples. Furthermore, gamma irradiation had no significant effects on protein solubility and the contents of free SH in LEW, while induced significant slight decreases in protein solubility and the contents of free SH in LEY. Cold storage, however, showed no significant effects on protein solubility and free SH in all liquid egg samples. FFA contents and PV of LEY lipids significantly increased post irradiation treatments and during storage, but the observed values were relatively low and acceptable. In addition, gamma irradiation at 3 kGy dose had no significant effects neither on the amino acid composition of LEW and LEY nor on fatty acid profiles of LEY lipids. The sensory preference did not alter neither for the liquid egg samples nor for scrambled egg samples that prepared from irradiated liquid egg products. Finally, gamma irradiation at 3 kGy dose appeared to be the optimum for treating LEW and LEY at room temperature followed by cold storage at 4 ± 1 °C.     

Admittance measurements to assess the total solids and fat contents in liquid whole egg products

In the present research, a method based on admittance measurements able to assess total solids and fat contents (%) in nine different liquid whole egg products was set up. By means of a tetrapolar platinum cell connected to a signal conditioning circuit, an alternating current generator and a data acquisition system, the effect of 15 different combinations of frequencies of the oscillating field (10, 100, 500, 1000 and 5000 Hz) and input voltage levels (1, 1.5 and 2 V) on the estimation of the total solids and fat contents were analyzed. The influence of the temperature solution on the electrical measurements was also assessed. The best estimations were obtained at 1000 Hz and 1 V (R² = 0.998; SE = 0.14%) for the total solids content and at 5000 Hz and 1 V (R² = 0.995; SE = 0.19%) for the fat content. For both parameters, the measurements conducted at 10 Hz appeared affected by the polarization occurring at the electrodes-solution interface. The admittance of the liquid whole egg products linearly increased with the temperature, and a temperature coefficient θ at 20 °C of about 2.1 was calculated. These excellent results encourage an industrial application of the technique for a rapid and economic assessment of the total solids and fat contents in the liquid egg products.     

Traceback Investigation for Salmonella Contamination at Egg Processing Plants in South Korea: Prevalence,Antibiotic Resistance,and Epidemiological Tracing by Rep‐PCR Fingerprinting

We conducted a survey of Salmonella from 8 egg‐breaking plants and a farm to determine the prevalence and the source of the bacteria. The contents of 2400 shell eggs (20 eggs per pool), 75 pasteurized liquid egg products, and 120 unpasteurized liquid egg products from 8 egg‐breaking plants in South Korea were examined. In liquid egg samples, 4 Salmonella‐positive samples from 120 unpasteurized ones (3.3%) and 5 positive samples from 75 pasteurized ones (6.7%) were identified; no eggs were positive for Salmonella among shell egg samples. To trace the source of Salmonella, we revisited the 2 Salmonella‐positive plants (plants A and C). We investigated the equipment and environments of the plants and a henhouse (farm A) that supplied shell eggs to plant A, and collected additional liquid eggs and shell eggs from plants A and C. All Salmonella isolates from plant A and the associated farm A, except for a single Typhimurium strain from farm A, were serotyped as Bareilly. Three serovars, including one Bareilly, four Tennessee, and one Richmond, were isolated from plant C. Most Salmonella isolates were susceptible to tested antibiotics. To identify differences between isolates, molecular subtyping by using the automated rep‐PCR system was conducted. All Salmonella Bareilly (S. Bareilly) strains from plant A exhibited high similarity, indicating possible contamination by Salmonella strains from the henhouse A. Meanwhile, 2 S. Bareilly strains from plant C, one from liquid egg at the 1st visit and the other from container at the 2nd visit, exhibited identical antibiotic resistance and similar subtyping pattern, but clearly discriminated from the ones of plant A.     

Rheological Properties of Liquid Egg Products (LEPS)

Rheological properties were determined at 4°C (refrigerated temperature), 25°C (room temperature), 60°C (pasteurization temperature) for liquid whole egg (LWE) and liquid egg yolk (LEY) and 4, 25, 55.6°C for liquid egg white (LEW) by using concentric cylinder viscometer. The shear rate range was 8 to 53.7 s^?1 for LEW and LWE, and 1 to 34 s^?1 for LEY. Selected physical properties (e.g., density) of LEPs were studied at broad range of temperatures from 4°C to 60°C. All liquid egg products (LEPs) exhibited mildly shear thinning (pseudoplastic) behavior. Experimental data of LWE and LEW successfully fitted Herschel-Bulkley model, LEY data were well described by power law model. LEW and LWE showed thixotropy and time-dependency at their pasteurization temperatures (55.6°C for LEW, 60°C for LWE) and considered being time-independent below these temperatures. LEY exhibited time-dependent behavior at 4°C and 60°C. But its rheological behavior showed no thixotropy and time-dependency at room temperature. The density of all three products decreased with increasing temperature. Density data were correlated by polynomial models (r² > 0.99).     

鸡蛋液发酵条件对蛋挞营养和风味的影响

利用乳酸乳球菌（Lactococcus lactis）、嗜热链球菌（Streptococcus thermophilus）和梅利斯丛梗孢酵母（Moniliella mellis）为发酵剂,采用单因素和正交试验设计,研究发酵剂接种量、发酵时间和发酵温度对蛋挞风味和质构的影响规律,得到最优发酵工艺条件为接种量2%、发酵温度42 ℃、发酵时间42 h,此条件下制备的蛋挞外形完整、无裂缝,蛋挞芯凝固成型、色泽亮黄,甜度适中,品质最佳。质构测定结果显示,最优条件下其硬度为87.8 g,黏附力为18.3 g,黏结性为74.3 g·mm,凝胶强度为730.6 g·mm。营养成分分析显示, 经过发酵后蛋液粗蛋白呈下降趋势,氨基酸总量、必需氨基酸和鲜味氨基酸质量分数由7.55%、3.26%和3.08%分别提高至9.13%、4.01%和5.15%,蛋液由中性（pH 7.6）转为弱酸性（pH 5.1）。利用气相色谱-质谱联用技术进行风味分析,显示发酵蛋液及其制备的风味蛋挞挥发性物质分别为24 种和46 种,未发酵蛋液及其制备的普通蛋挞挥发物质分别为15 种和31 种。发酵蛋挞特征风味成分主要为己醛、壬醛、乙偶姻、丁酰乳酸丁酯、2,5-二甲基吡嗪,呈现独特的芳香风味。本研究利用蛋液发酵手段制备蛋挞的风味与营养更加丰富,为发酵蛋制品在烘焙食品中的应用提供一定理论基础。     

Characterization of lipids and antioxidant capacity of novel nutraceutical egg products developed with omega‐3‐rich oils

BACKGROUND: Cardiovascular disease has had an unquestioned status of the number one cause of death in the US since 1921. Omega‐3 polyunsaturated fatty acids (ω‐3 PUFAs) have cardio‐protective benefits. However, egg is typically a poor source of ω‐3 PUFAs and, in general, the American diet is low in these cardio‐protective fatty acids. Novel, nutritionally enhanced egg products were developed by substituting yolk with ω‐3 PUFA‐rich flaxseed, menhaden, algae, or krill oil. Experimental egg products matched composition of hen egg (whole egg). The experimental egg products, mixed whole egg, and a liquid egg product (Egg Beaters^?) were microwave‐cooked and compared. RESULTS: Although fat, protein, and moisture contents of experimental egg products matched (P > 0.05) mixed whole egg, experimental egg products had more (P < 0.05) ω‐3 PUFAs, lower (P < 0.05) ω‐6/ω‐3 ratio, and depending on oil added, a higher (P < 0.05) unsaturated/saturated fatty acids ratio compared to mixed whole egg. Triglycerides were the main lipid class in all experimental egg products except those developed with krill oil, which had even more phospholipids than mixed whole egg. Analysis of thiobarbituric acid reactive substances showed that lipid oxidation of experimental egg products was lower (P < 0.05) or similar (P > 0.05) to mixed whole egg, except for experimental egg products with krill oil. However, peroxide value showed that all egg samples had minimal oxidation. Experimental egg products developed with menhaden or flaxseed oil had the highest (P < 0.05) concentration of the antioxidant, ethyoxquin compared to all other egg samples. However, experimental egg products with krill oil likely contained a natural antioxidant, astaxanthin. CONCLUSION: This study demonstrated an alternative approach to developing novel, nutraceutical egg products. Instead of dietary modification of chicken feed, yolk substitution with ω‐3 PUFAs oils resulted in enhancement of ω‐3 PUFAs beyond levels possible to achieve by modifying chicken feed. Copyright © 2011 Society of Chemical Industry     

Effects of ohmic heating on technological properties of whole egg

The aim of this work was to study the effects of different ohmic heating conditions on color, rheology, foaming, and gelling properties of whole egg. Industrial products treated by conventional heat pasteurization and the corresponding raw materials were also evaluated. Ohmic treatments accomplished in a static cell (65.5 °C × 3 min, 70 °C × 1 min, and 67 °C × 4.5 min) increased whole egg apparent viscosity (up to 190%), but also foam overrun (up to 28%) and gel hardness (up to 15%). The performance improvement was confirmed by treatments carried out in a continuous pilot plant (71 °C × 0.6 min, 68 °C × 1.4 min) and the products resulted stable during storage at 4 °C for 30 days. In conclusion, this study demonstrated that ohmic heating is a suitable alternative to conventional pasteurization. Low temperature treatments are preferable to avoid possible rheological issues due to protein denaturation.Industrial relevanceWhole egg is a protein ingredient with multiple technological properties, used in many foods. Due to safety reasons, food manufacturers often use pasteurized liquid egg products, microbiologically safer and easier to handle with respect to shell eggs. In order to satisfy the required sanitary levels for liquid egg products, thermal pasteurization treatments are needed. However, since egg proteins are very sensitive to high temperatures, attention must be paid to avoid coagulation entailing deleterious effects against egg quality. In this study, different ohmic heating treatments were evaluated as milder alternatives to conventional pasteurization. The lab- and pilot-scale experiments and the subsequent statistical analyses of the obtained results contributed to assess the effects of the different ohmic treatments on technological features (e.g. color, rheology, foaming, and gelling properties) of liquid whole egg. This study demonstrated that ohmic heating is a suitable technology for whole egg treatment, paving the way for new opportunities in order to produce safe food ingredients with improved technological functionalities.     

Optimization of iron supplementation for enhanced detection of Salmonella Enteritidis in eggs

Mixed raw egg contents were inoculated with approximately 10 CFU of Salmonella Enteritidis and supplemented with 0 to 7 mg of FeSO4 per g of egg contents. Egg contents were then incubated at 37 degrees C, and Salmonella Enteritidis colonies were enumerated for up to 106 h. Iron supplementation significantly enhanced the growth of Salmonella Enteritidis. Within the first 24 h of incubation, the optimum iron level for Salmonella Enteritidis growth in egg contents was between 0.2 and 2 mg of FeSO4 per g of egg contents. After 24 h of incubation at 37 degrees C. Salmonella Enteritidis counts in eggs supplemented with 0.5 mg of FeSO4 per g of egg contents consistently reached approximately 1 x 10(9) CFU/ml, whereas Salmonella Enteritidis counts in eggs without iron supplementation varied from less than 5 CFU/ml to 8.4 x 10(6) CFU/ml. A 3 by 3 factorial design was used to study the effect of type of preenrichment and level of iron supplementation on the growth of Salmonella Enteritidis in egg contents. No significant differences in Salmonella Enteritidis counts between preenrichment and nonpreenrichment treatments were observed when egg contents were supplemented with 0.5 mg of FeSO4 per g of egg contents. It was concluded that preenrichment was not necessary for isolation of Salmonella Enteritidis from eggs. The effect of iron supplementation on the sensitivity of detection by the direct plating method was investigated. The direct plating method detected a significantly higher percentage of Salmonella Enteritidis in raw egg contents supplemented with 0.5 mg of FeSO4 per g of egg contents (90%) than in raw egg contents without iron supplementation (63.3%).     

Brown potato croquettes low in acrylamide by coating with egg/breadcrumbs

Potato croquettes are preparations of mashed potato or potato powder with milk powder or egg, fried in oil or baked in the oven. Product identity calls for fairly strong browning, which may cause high acrylamide contents. Prefabricates from the Swiss market resulted in products of intermediate acrylamide content (50–570 µg/kg), strongly depending on frying conditions. The potential of acrylamide formation of these products was modest, since the potato powder used was low in reducing sugars and asparagine. Defatted milk powder increased the 120 °C potential by 200–700 µg/kg (lactose), whereas egg was approximately neutral. Coating with egg/breadcrumbs resulted in stronger browning and at the same time in reduced acrylamide formation. It shields the potato from the heat by a material the browning of which is not linked with acrylamide formation. Croquettes prepared from fresh potato confirmed that coating with egg/breadcrumbs improves the product quality while strongly decreasing the acrylamide content.     

Functional properties of pasteurised liquid whole egg products as affected by the hygienic quality of the raw eggs

The viscosity, foaming and baking performances of pasteurised liquid whole egg products were investigated to study the influence of raw egg hygienic quality on egg product functional performances. Uracil, lactic acid and 3OH-butyric acid measured in the pasteurised egg products were taken as chemical indices of the hygienic quality of the raw material. A high variability in the functional properties was observed, especially for overrun and foam stability, as well as in the chemical indices of hygiene. Many interesting correlations were found between variables, for example between overrun and cake volume (p < 0.001). Instead, no significant correlations were found between the chemical indices and the different functional properties. However, the application of Principal Component Analysis demonstrated that a good hygienic quality of the raw material used to prepare the liquid whole egg products is a prerequisite needed to develop good functional performances, although other factors pertaining to composition or processing also have a role.     

Denaturation of egg antigens by cooking

Changes in egg protein contents by cooking were measured with an ELISA kit using Tris-HCl buffer in model foods including cake, meatballs, pasta and pudding made with whole egg, egg-white and egg-yolk. The egg protein contents were lowest in the deep-fried model foods of cakes and meatballs. Ovalbumin (OVA) was undetectable (<1 μg/g) and ovomucoid (OVM) was lowest in pouched meatballs, suggesting that processing temperature and uniform heat-treatment affect the detection of egg protein. Furthermore, egg protein contents were below 6 μg/g in the pouched meatballs and pasta made with egg-yolk, and OVA and OVM were not detected by Western blotting analysis with human IgE from patients' serum. On the other hand, processed egg proteins were detected with an ELISA kit using a surfactant and reductant in the extract buffer.     

Occurrence of beta-hydroxybutyric acid in incubator reject eggs.

A simplified method for extraction of β-hydroxybutyric acid from whole egg prepared from incubator reject eggs is described. It is concluded that the presence of 15.95 ± 8.54 mg of β-hydroxybutyric acid per 100 g of liquid whole egg would strongly indicate that the egg had been prepared from incubator reject eggs. There is no obvious correlation between the numbers and types of bacteria present and the amounts of β-hydroxybutyric acid found in incubator reject eggs. The relative merits of a test for the presence of incubator reject egg in egg products based on the estimation of β-hydroxybutyric acid as opposed to alternative proposed tests, described in the literature, are reviewed.     

Ohmic Heating of Liquid Whole Egg: Rheological Behaviour and Fluid Dynamics

Although ohmic heating is used as an alternative heating method for liquid egg products commercially, there is a lack of information on the change of rheological properties and fluid dynamics characteristics of ohmically heated liquid whole egg in the literature. The change of rheological behaviour of the ohmically heated liquid whole egg, across a temperature range of 4–60 °C, was determined by using a concentric rotational viscometer. The ohmic heating was conducted by applying the voltage gradient (20 V/cm) at 50 Hz. The temperature dependency of the electrical conductivity of liquid egg was linear (R ² = 0.999). The rheological behaviour was found to be shear thinning since power law model had higher regression coefficient and lower χ ² and root mean square error values than Newtonian model. Ohmically heated liquid whole egg exhibited higher degree of thixotropic index indicating the occurrence of the protein denaturation at 60 °C. The flow behaviour of liquid whole egg in the continuous ohmic heating system was predicted as laminar (GRe range of 87.59–538.87) for the mass flow rate range of 0.0056–0.0166 kg/s. The friction factors and pressure losses in the system in those mass flow rates were also assessed. The result of this study will give necessary information on flow characteristics of liquid whole egg for the modelling, designing and the scaling up of the continuous ohmic heating systems for pasteurisation of liquid egg products.     

SELECTED PHYSICAL PROPERTIES of LIQUID EGG PRODUCTS AT PASTEURIZATION TEMPERATURES

The influence of temperature on the rheological properties and density of liquid egg product at pasteurization temperatures was investigated. the density of all these products decreased with increasing temperature: however, the changes were different depending on the product. the change in density may be represented by simple linear equations. All the products showed pseudoplastic flow behavior that may be described by the Power-law model. Egg white had the lowest power law index (n=0.552). Salted egg yolk had the highest n value (>0.8), thus it is closer to Newtonian fluid in its behavior. This index did not vary greatly with temperature for whole egg and egg white but decreased with temperature for egg yolk and salted egg yolk the lowest consistency coefficient (m=54.52mPa.sⁿ) was observed for whole egg. Salted egg yolk had the highest m value (269.9mPa.sⁿ). Them value increased with temperature for egg yolk and egg white, but decreased with temperature before showing an increase for salted egg yolk and egg white. the calculated Generalized Reynolds number was below 2100 for all the products. These results show that laminar flow exits during typical pasteurization of liquid egg products and therefore the minimum residence time is half the average resident time.     

Dielectric properties of egg whites and whole eggs as influenced by thermal treatments

Effects of cooking on dielectric properties of liquid whole eggs and liquid egg whites were studied in connection with radio frequency and microwave heating processes to preserve shelf-stable products. Dielectric measurements were made using an open-ended coaxial probe method over a temperature range of 20 and 120 °C at radio frequencies 27 and 40 MHz, and microwave frequencies 915 and 1800 MHz. Thermal denaturation of liquid egg whites and whole eggs influenced the dielectric constants and dipole loss component of eggs, as reflected by changes in loss factors above 60 °C. In addition, loss factor of liquid whole eggs was generally smaller than that of egg whites and larger than the loss factor of egg yolk. Ionic conductivity was a dominant factor determining the dielectric loss behavior of egg products at radio frequencies, whereas dipole water molecules played an increasing role with an increase in microwave frequencies.     

Electrical Conductivities of Liquid Egg Products and Fruit Juices Exposed to High Pulsed Electric Fields

Electrical conductivity can be used to monitor important changes in a food product during pulsed electric field (PEF) processing. Electrical conductivities of selected fruit juices (namely apple, orange, and pineapple juices) and liquid egg products (namely whole egg, yolk, and egg white) were determined online during a PEF treatment. The property was measured at broad processing temperatures ranging from 5 to 55°C. Electrical conductivity increased linearly with increasing temperatures for all the products. The liquid egg products have the highest overall electrical conductivity varying from 0.22 to 1.1 S/m whereas fruit juice products have the lowest electrical conductivity ranging from 0.13 to 0.63 S/m. Regression equations of electrical conductivity as functions of temperature were developed. This paper provides a database and equation correlations of food electrical conductivity that could be used to design and optimize PEF process.     

EFFECT OF RAPID COOLING OF SHELL EGGS ON MICROCRACK DEVELOPMENT, PENETRATION OF SALMONELLA ENTERITIDIS, AND EGGSHELL STRENGTH

Eggs were subjected to cryogenic cooling treatments using liquid CO₂ or liquid N_2. In order to minimize the thermal stress in eggshells due to rapid cooling, a two-stage air-cooling method was also evaluated in this study. Eggs were cooled from an initial temperature of 25C to approximately 7C. It was found that cooling produced microcracks on eggshells. However, rapid cooling did not increase the penetration of Salmonella enterica serovar Enteritidis (Salmonella enteritidis) into egg contents. When egg contents alone were sampled for Salmonella enteritidis, extending the immersion time from 24 to 48 h significantly (P < 0.01) increased the penetration of Salmonella enteritidis from 5.0 to 25.0%. When egg contents together with eggshells were sampled, Salmonella enteritidis was detected in 100% of the egg samples at the above two time intervals. There were no significant differences (P > 0.05) in the eggshell strength between control (no cooling) and cooling treatments, indicating that cooling did not weaken eggshell strength.