Effect of the storage temperature on the quality of eggs inoculated with Salmonella Enteritidis onto shell

This study explored the temperature-dependent effect on the growth characteristics of Salmonella Enteritidis (SE) on eggshell toward identifying an appropriate storage temperature for unwashed eggs in an actual distribution environment. Among the test storage temperatures (10 °C, 25 °C, and 35 °C), 25 °C was determined to be an appropriate storage temperature, with no effect of changing temperature on the control of SE on eggshell. Regarding the effect of the temperature on egg quality, the quality indicators of egg such as Haugh unit, yolk index, albumin index, and albumin pH were significantly maintained. These results indicated that unwashed eggs should be distributed at 25 °C for SE control, and the storage temperature should be below 10 °C from at least day 4 onward after the start of distribution to maintain egg quality. This study will assist for safety management of unwashed egg in an actual distribution environment.

Quality characteristics, lysozyme activity, and albumen viscosity of fresh hatching duck eggs after a week's storage at various temperatures

The study aimed to analyze the qualitative features of Cherry Valley duck' hatching eggs during storage at different temperatures. Eggs were divided into 3 equal groups with 30 eggs each: fresh egg and stored at 7 °C and 17 °C within one week. Qualitative analyses of duck eggs were carried out, considering the morphological composition, physicochemical characteristics, lysozyme activity, and albumen viscosity. The highest weight of yolk and its percentage was found in the 17 °C group. The weight and percentage of albumen were significantly the highest in the group of fresh eggs. Higher egg weight loss was observed in the group stored at higher temperatures. Higher thick albumen height and Haugh units were found in fresh eggs and eggs stored at 7 °C. Different temperatures of egg storage did not affect lysozyme activity in thick and thin albumen. Stored eggs were characterized by lower albumen viscosity only at a shear rate of 10 rpm. The higher viscosity of thick albumen compared to thin ones was demonstrated at 10 and 20 rpm shear rates. The presented research results indicate a large diversity of selected qualitative indicators of hatching duck eggs, which may affect their storage and suitability for incubation.

Combination of sensory evaluation with conventional physiochemical analyses to evaluate quality changes during long-term storage and estimate the shelf life of chicken eggs

1. This study developed a comprehensive sensory evaluation system that consisted of descriptions corresponding to United States Department of Agriculture photos to evaluate overall acceptability, albumen and yolk appearances and odours. It determined physiochemical parameters of eggs stored at 7°C (7W12 and 7U12 for washed and unwashed, respectively) for 12 weeks and stored at 25°C (25W4 and 25U4 for washed and unwashed, respectively) for four weeks.2. Throughout storage, there was a general downward trend in Haugh units (HU) and yolk index and an upward trend in air cell size, weight loss and S-ovalbumin content were observed (P < 0.05). The 25W4 and 25U4 egg quality rapidly deteriorated from grade AA (HU 81.7) to grade B after two weeks (HU 46.5 and 49.6), whereas 7W12 and 7U12 eggs remained grade A after 12 weeks (HU 67.3 and 66.9). High correlations were observed between the sensory and physiochemical parameters (i.e., R2 = 0.93, 0.93, 0.88 and 0.94 for albumen appearance, yolk appearance, sensorial odour and overall acceptability, respectively, with HU in 25W4 eggs).3. Eggs stored at 25°C and classified into 'premium', 'class I', and 'class II' on the basis of their HU had estimated shelf life of 0.5, 1.5 and 2.5 weeks, while shelf lives of 4, 9 and 15 weeks were estimated for 7°C-stored premium, class I and II eggs, respectively.4. In conclusion, distinct HU requirements for eggs of different quality classes under two storage temperatures need to be established. Incorporating sensory evaluation with conventional physiochemical analyses is promising to assess and estimate egg quality changes. Further research work about the influences of different storage temperatures and possible temperature fluctuations during storage on egg quality changes is needed.

Metabolomics reveals changes in metabolite composition of duck eggs under the impact of long-term storage

BACKGROUND

Eggs are essential food sources as they provide low cost and high nutritional content of animal protein. The preservation period is one of the apparent factors affecting egg quality. Previous studies based on traditional detection techniques demonstrated that storage period would significantly influence egg weight, eggshell weight, albumen height, haugh unit (HU) and albumen viscosity. Herein, we employed non-targeted metabolome technology to reveal the comprehensive changes in metabolite composition in duck eggs under the impacts of storage period.

RESULTS

The results showed that the primary metabolites in the yolk of duck eggs are amino acids, carbohydrates and lipids. In contrast, the primary metabolites in the albumen are amino acids, benzene and indoles. We screened 43 and 16 different metabolites, respectively, in the albumen and yolk of duck eggs with different preservation periods. In addition, kyoto encyclopedia of genes and genomes (KEGG) enrichment was performed, and the results showed that various nutrients were degraded in the egg after preservation, thus affecting the quality of duck eggs. These nutrients included amino acids, fatty acids, nucleotides, sugars and vitamins; meanwhile, ammonia, biogenic amines and some flavor substances were produced, affecting the quality of the eggs.

CONCLUSION

Ourfindings can contribute to a holistic understanding of metabolite composition changes in duck eggs during deterioration in storage. © 2022 Society of Chemical Industry.

Impacts of polyphenols on laying hens' productivity and egg quality: A review

There has been a rapid increase in the world's output of main poultry products (meat and eggs). This reflects customer desire for these high-quality and safe products and the comparatively low price. Recently, natural feed additives, plants and products have been increasingly popular in the poultry and livestock industries to maintain and improve their health and production. Polyphenols are a type of micronutrient that is plentiful in our diet. They are phytochemicals that have health benefits, notably cardiovascular, cognitive function, antioxidant, anti-mutagenic, anti-inflammatory, antistress, anti-tumour, anti-pathogen, detoxification, growth-promoting and immunomodulating activities. On the other hand, excessive polyphenol levels have an unclear and sometimes negative impact on gastrointestinal tract health, nutrient digestion, digestive enzyme activity, vitamin, mineral absorption, laying hens performance and egg quality. As a result, this review illuminated polyphenols' various sources, classifications, biological activities, potential usage restrictions and effects on poultry, layer productivity and egg external and internal quality.

Potential Implications of Natural Antioxidants of Plant Origin on Oxidative Stability of Chicken Albumen during Storage: A Review

Enhanced albumen quality is reflected in increased thick albumen height, albumen weight, and Haugh unit value, while the antimicrobial, antioxidant, foaming, gelling, viscosity, and elasticity attributes are retained. Improved albumen quality is of benefit to consumers and to the food and health industries. Egg quality often declines during storage because eggs are highly perishable products and are most often not consumed immediately after oviposition. This review provides insights into albumen quality in terms of changes in albumen structure during storage, the influence of storage time and temperature, and the mitigation effects of natural dietary antioxidants of plant origin. During storage, albumen undergoes various physiochemical changes: loss of moisture and gaseous products through the shell pores and breakdown of carbonic acid, which induces albumen pH increases. High albumen pH acts as a catalyst for structural changes in albumen, including degradation of the β-ovomucin subunit and O-glycosidic bonds, collapse of the ovomucin-lysozyme complex, and decline in albumen protein–protein interactions. These culminate in declined albumen quality, characterized by the loss of albumen proteins, such as ovomucin, destabilized foaming and gelling capacity, decreased antimicrobial activity, albumen liquefaction, and reduced viscosity and elasticity. These changes and rates of albumen decline are more conspicuous at ambient temperature compared to low temperatures. Thus, albumen of poor quality due to the loss of functional and biological properties cannot be harnessed as a functional food, as an ingredient in food processing industries, and for its active compounds for drug creation in the health industry. The use of refrigerators, coatings, and thermal and non-thermal treatments to preserve albumen quality during storage are limited by huge financial costs, the skilled operations required, environmental pollution, and residue and toxicity effects. Nutritional interventions, including supplementation with natural antioxidants of plant origin in the diets of laying hens, have a promising potential as natural shelf-life extenders. Since they are safe, without residue effects, the bioactive compounds could be transferred to the egg. Natural antioxidants of plant origin have been found to increase albumen radical scavenging activity, increase the total antioxidant capacity of albumen, reduce the protein carbonyl and malondialdehyde (MDA) content of albumen, and prevent oxidative damage to the magnum, thereby eliminating the transfer of toxins to the egg. These products are targeted towards attenuating oxidative species and inhibiting or slowing down the rates of lipid and protein peroxidation, thereby enhancing egg quality and extending the shelf life of albumen.

Do the differences in egg contamination, penetration, and resistance against microorganisms among the hen genotypes exist?

The aim of this study was to evaluate and compare the impact of genotype and storage conditions (temperature and time) on microbiological contamination and eggshell quality. There were four genotypes of laying hens used, Czech golden spotted (CGS), Greenleg Partridge (GP), White Leghorn (WL) and commercial hybrid (CH) hens were included. After collection, the eggs were divided equally into five groups regarding the storage time (0, 14, 28 days) and temperature (5 and 20 °C). The microbiological analysis included counting of colonies forming units (CFU) of Escherichia coli (EC), Enterococcus (ENT) and total number of microorganisms (TNM) on eggshell surface, eggshell membranes and in thin albumen. The analysis of eggshell quality included the determination of eggshell proportion (SP), thickness (ST), strength (SST), index (SI) and surface (SS). Moreover, egg weight (EW) and egg weight loss (EWL) were determined. The significant effect of genotype was found in contamination of eggshell by EC, ENT and TNM, eggshell membranes by TNM and albumen by EC (all P ≤ 0.05). The significantly lowest contamination of eggshell from EC was in eggs from the WL hens (4.42 log CFU/eggshell), while from ENT was in eggs from the CGS hens (1.22 log CFU/eggshell) and from the WL hens (1.40 log CFU/eggshell). The lowest incidence of TNM was also detected in eggs from the WL hens (5.03 log CFU/eggshell). Statistically the lowest contamination of eggshell membranes by TNM was found in eggs from the WL (0.12 log CFU/eggshell membranes) and CH hens (0.15 log CFU/eggshell membranes). Regarding the effect of genotype, the GP (not detected) and WL (not detected) hens was in eggs with statistically the lowest occurrence of EC bacteria in albumen. Regarding the EW and eggshell quality, all the parameters were significantly affected by the genotype (P ≤ 0.0001). Also EWL was significantly (P ≤ 0.05) affected by genotype (after 14, 21 and 28 days of storage). There were found to be significant differences of microbial contamination of egg surface among observed hen genotypes. The penetration of selected microorganisms was also significant in contamination of eggshell membranes by TNM and in contamination of albumen by EC.

Development of predictive models for egg freshness and shelf-life under different storage temperatures

The objective of the present study was to develop models for egg freshness and shelf-life predictions for the selected evaluation indicators including egg weight, Haugh unit (HU), and albumen height. Experiments were carried out at different storage temperatures for a total period of 29–32 days. All data were collected and fitted in to Arrhenius equation for egg freshness, while the HU data were applied to a probability model for shelf-life prediction. The results showed that egg weight, albumen height, and HU decreased significantly, while albumen pH increased with the extension of storage time. The higher the storage temperature, the faster the egg quality decreased. In addition, the bias factor, accuracy factor, and the standard error of prediction were selected to verify the developed quality models. Maximum rescaled R-square statistic, the Hosmer–Lemeshow goodness-of-fit statistic, and the receiver operating characteristic curve were used to evaluate the goodness-of-fit of the developed probability model for the shelf-life of eggs, which indicated that the presented predictive models can be used to assess egg freshness and predict shelf-life during different storage temperatures.

Effect of dietary pumpkin (Cucurbita moschata) seed meal on layer performance and egg quality characteristics

Objective

The objective of this study was to investigate the of dietary pumpkin (Cucurbita moschata) seed meal (PSM) on laying performance, quality, fatty acids, cholesterol, antioxidant compounds and shelf life of eggs.

Methods

Eighty Tetra SL laying hens, 50-week-old, were randomly divided into two equal groups, having 10 replicates with 4 birds in each. The control (CON) treatment was fed with basal diet, while experimental treatment was fed a diet with 9% pumpkin seed meal (PSM), for a 6 week period.

Results

Dietary PSM significantly decreased average daily feed intake (p<0.05), with no significant effect on other performance parameters. The PSM, enriched the eggs with polyunsaturated fatty acids, especially α linolenic acid (0.33 vs. 0.21g/100g) and linoleic acid (20.65 vs. 18.37 g/100g), whereas it reduced the amount of arachidonic acid with 3.91% and n-6/n-3 ratio in PSM eggs compared with CON. The inclusion of 9% PSM significantly (p<0.05) diminished the cholesterol concentration in yolk with 11.31% and in egg with 10.38%, in respect to the CON samples. The significantly (p<0.05) higher concentration of polyphenols and antioxidant compounds, determined in PSM eggs, proved to be effective on shelf life of eggs preserved at refrigerator (5°C) and room temperature (21°C) for 28 days, by delaying the lipid oxidation and protein denaturation. This effect was reflected in significantly (p<0.05) higher Haugh Unit in eggs stored 28 days at 21°C and lower albumen pH values for the overall storage time, both at 5°C and 21°C, proving the antioxidant effect of pumpkin.

Conclusion

Dietary PSM supplementation was significantly effective on average daily feed intake and egg quality by increasing some fatty acids while lowering the cholesterol concentration. Also, PSM proved to be effective improving shelf life of eggs for 28 days storage time.

Egg characteristics of Japanese quail fed diets containing guava extract (Psidium guajava L.)

The main purpose of this study was to evaluate the characteristics of eggs produced by Japanese quails fed with guava extract. A total of 400 eggs collected from the quails fed with experimental diets, were distributed in a completely randomized design in factorial arrangement 4 x 4 with main effects including four dietary levels of guava extract (0, 3, 6 and 9 g kg-1) and four storage periods (0, 9, 18 and 27 days) totalizing 16 treatments with five replicates of five eggs. The eggs were produced by Japanese quails, fed with experimental diets. The diets were isonutritive formulated by corn-soybean basis. The eggs were stored for different periods, at the same conditions, to constitute the treatments. The parameters evaluated were egg weight loss (g and %), yolk color, Haugh unit, specific gravity, eggshell thickness and pH of the yolk and albumen. Data were submitted to ANOVA, and means were compared using Scott-Knott test, using α = 0.05. The specific gravity of fresh eggs was better with the use of 6 g kg-1 of guava extract in the diet. The use of 3 g kg-1 of guava extract resulted in smaller eggshell thickness of fresh eggs. The Haugh unit was affected just by the storage periods. The dietary guava extract (3, 6 or 9 g kg-1) increased the pH of albumen in eggs stored for 27 days. The use of 6 g kg-1 of guava extract in quails diet increase the specific gravity in fresh eggs and increase the yolk color when the eggs are stored.

Guinea fowl (Numida meleagris) eggs and free-range housing: a convenient alternative to laying hens' eggs in terms of food safety?

The aim of this study was to evaluate the impact of the genotype (guinea fowl, native breed Leghorn, and commercial hybrid hens), storage time (0, 14, 28 d) and storage temperature (fresh, 5, 20°C) on eggshell quality traits and microbiological contamination of eggshell, eggshell membranes, and albumen. A total of 150 hens (50 hens per genotype—divided into 2 equal groups because of the results replication) were used. There were 150 eggs (50 per genotype) used for microbial analysis and 600 eggs used for the analysis of eggshell quality. The effects of genotype, storage time, and storage temperature were observed. Moreover, interactions between these factors were calculated. The significant effect of genotype (P = 0.0001) was found in egg weight, in all observed parameters of eggshell quality (proportion, thickness, strength, surface, and index), eggshell contamination of Escherichia coli (EC) and total number of micro-organisms (TNM), penetration of TNM into eggshell membranes (P = 0.0014), and penetration of TNM into albumen (P = 0.0019). Storage time significantly affected egg weight and all parameters of eggshell quality except the eggshell strength and index. It also significantly affected count of Enterococcus (ENT) on eggshell, TNM in eggshell membranes and TNM in albumen. Storage temperature significantly influenced egg weight (P = 0.0001) and all parameters but eggshell thickness and surface. Regarding the microbial contamination, storage temperature significantly affected a count of ENT on shell, TNM in shell membranes, and TNM in albumen. Concerning significant interactions, the interaction among genotype and storage time was found significant (P = 0.0148). Fresh and 28-day-old commercial hybrid eggs were the most contaminated, whereas guinea fowl eggs (fresh and 14 d old) and Leghorn hen eggs (fresh, 14, 28 d old) had the lowest level of contamination by EC. When looking for an alternative to laying hens, guinea fowls should be taken into consideration due to their higher resistance to diseases, ability of adaptation to different environmental conditions, and especially in terms of eggshell quality and therefore egg safety.

Comparison the Zn-Threonine, Zn-Methionine, and Zn Oxide on Performance, Egg Quality, Zn Bioavailability, and Zn Content in Egg and Excreta of Laying Hens

The experiment was conducted to investigate the effect of supplementary zinc-threonine (Zn-Thr), zinc-methionine (Zn-Met), and zinc oxide (ZnO) on the laying performance, egg quality, Zn content in egg and excreta. One hundred and sixty hens (Hy-Line W36) were randomly divided into 10 treatments with 4 replications of 4 hens each. During the first 4 weeks, groups were fed a corn-soy basal diet without extra zinc (30.3 mg Zn/kg diet) to depletion storage zinc from the body and it was used as the control diet. During the ensuing 10 weeks from 36 to 45 weeks of age, 3 levels of 30, 60, and 90 mg Zn/kg were added to the diet by ZnO, Zn-Met, and Zn-Thr sources. Results showed that there were no significant differences between the experimental treatments in terms of egg weight, feed intake, eggshell weight, eggshell percentage, and albumen weight. In total experimental period, the supplementation of Zn-Met and Zn-Thr decreased feed conversion ratio and increased egg mass and egg production compared with ZnO 30 and 60 mg Zn/kg and control treatments (P < 0.05). The results showed that treatment effect on Zn content in egg and excreta was significant (P < 0.05). It is concluded that diets supplied with lower levels of organic Zn can maintain egg production performance, improve egg quality, enrich eggs, increase bioavailability, and reduce the negative effects of age on egg quality characteristics in laying hens compared with their oxide form.

Turmeric powder in the diet of Japanese quails improves the quality of stored eggs

SUMMARY This study evaluated the effect of turmeric powder (TP) on the productivity and egg quality of quails and on the quality of eggs stored at different temperatures for 7 or 14 d. Quails were distributed in three treatments that consisted of sorghum-based diets with 1.5% and 3% TP or zero TP inclusion, with five replicates for 84 d. Eggs were stored at ambient temperature or refrigerated for 7 or 14 d in a 3 × 2 × 2 factorial arrangement with three TP levels × two storage temperatures (ST) × two storage periods (SP). Inclusion of TP did not affect the performance of the quails or egg quality at 84 d. Interaction SP × ST influenced the height and diameter of yolk and albumen, and the Haugh unit value. Eggs of quails with a diet supplemented with 3% TP and stored for 14 d showed specific gravity similar to the eggs stored for 7 d, despite the TP supplementation. It was concluded that diets with 3% TP did not affect the performance and quality of fresh eggs but improved the quality of eggs stored for 14 d at ambient temperature.

Bee pollen improves productivity of laying Japanese quails

SUMMARY This study aimed to evaluate the effects of bee pollen (BP) on the performance of laying Japanese quails and egg quality. A total of 60 quails were used in a completely randomized experimental design with four treatments (0%, 0.5%, 1%, and 1.5% BP inclusion in diets) and five replicates. At the end of the study, productive performance and egg quality were evaluated; 160 eggs were maintained at different temperatures based on a completely randomized design and factorial arrangement (4 × 2), with four BP levels (cited above) and two storage temperatures (room temperature and refrigeration) for 14 days, totaling eight treatments with four replicates. BP levels did not influence (P> 0.05) feed conversion; however, daily feed intake, laying rate, egg mass, and weight and percentage of albumen increased. Yolk percentage decreased due to the augmentation of BP in diets. There was no effect (P> 0.05) of interaction of storage temperature × BP levels on egg quality, except with regard to the Haugh unit. BP supplementation resulted in higher egg weight and index of yolk and albumen. Refrigerated eggs had better internal quality than normal eggs. BP inclusion in diets of Japanese quails improved bird performance and the quality of fresh and stored eggs.

The Influence of Hen Aging on Eggshell Ultrastructure and Shell Mineral Components

The eggshell, which is a complex and highly ordered structure, is very important factor for food safety and egg marketing. This study investigated the changes in eggshell structure and shell components in relationship to hen age. For this study, we examined the histological change of the endometrium of the 30-, 60-, and 72-wk-old commercial layers, and analyzed the ultrastructure and ionic composition of their eggshells. The results showed that histological deformation, fibrosis, atrophy and elimination of micro-villi in the uterus endometrium were found through microscopic observation that was associated with increasing hen age. Concentration of blood-ion components such as Ca2+, Na+, K+, and Cl- ions did not change with age. Along with the results from the ultrastructure analysis of the eggshell, the palisade layer ratio and the density of mammillary knobs were significantly decreased in older hens. In addition, the type B mammillary knobs were frequently observed with increasing hen age. In the mineral element assay from the eggshell, Ca2+, S2-, and Co2+ significantly decreased with increasing hen age, whereas Na+, K+, and V2+ significantly increased. Therefore, the damages of endometrial tissue inhibit the processes of ion transmission and the crystallization of eggshell formation, resulting in a large and non-uniform mammillary knob formation. This means the conditions of endometrial cells affect the formation of the eggshell structure. In conclusion, hen aging causes the weakness of the eggshell and degrades the eggshell quality.