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In order to investigate the effect of conventional packaging forms on the freshness of market shell eggs, this research investigated shell egg freshness of Roman pink in paper-based packaging without overlapped eggs arrangement, paper-based packaging with overlapped eggs arrangement, foam-based cushioning packaging, carton-based packaging, plastic-based packaging 5 groups. The shell eggs were stored at 25 ℃ for 30 d, and evaluated weight loss, air space diameter and height, yolk index, Haugh unit, thick-to-thin albumen ratio and albumen pH at 0, 10, 20, 30 d. The results showed that in shell eggs treated with paper-based packaging with overlapped eggs arrangement had significantly (P

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Shell egg freshness is the key factor of evaluating egg quality. This review summarizes evaluation methods, influence factors of shell egg freshness, methods of retarding shell egg freshness deteriorations and future research directions of shell egg freshness. The results shows that egg freshness can be possibly evaluated by combination of destructive testing technology and non-destructive testing technology in an objective, dynamic and on-line manner. Hen age, diet, storage, transportation and environmental conditions can make a great influence on shell egg freshness. The characteristics of shell egg freshness can be possibly well maintained by adopting young hen, balanced nutrition diets, low temperature storage and avoiding mechanical damages during transportation and storage. Sterilization, packaging and coating methods can probably retard shell egg freshness deteriorations. Partially/totally adopting green, high efficient and energy-saving non-conventional food sterilization methods, and active, biodegradable and intelligent packaging/coating methods can possibly avoid microbial spoilage and retard egg freshness deteriorations during egg preservation. More researches of non-destructive testing technologies, diet formulations, simulating actual production, storage, transportation and sales, as well as optimization of non-conventional food sterilization-packaging and coating technologies need to be further explored, thus achieving quality improvement and industry promotion of shell eggs.

ABSTRACT: The purpose of this study is to investigate the characteristics of egg consumption in China and the production of functional eggs, and finally enrich the types of shell egg products. Trial 1 explored the influence of egg quality on Chinese consumers' willingness to purchase eggs through a questionnaire, which investigated 1,317 consumers' preferences for egg appearance, factors influencing egg purchase, and purchase of functional eggs. The results showed that about 65% of respondents ate more than 4 eggs per wk, pink eggs were the most popular in China, about 65% of consumers preferred eggs with an egg weight of 48 to 58 grams. For functional eggs, 75.32% of consumers have never heard of them. Preferences for eggshell color and yolk color varied by geographic region, with darker colors preferred in Northeast China. Based on the survey results of functional eggs consumption in Trial 1, the dwarf layers of China Agricultural University were used in Trial 2 to produce functional eggs. The eggs are small and pink in color, which is in line with the preferences of Chinese consumers. Three hundred dwarf layers were divided into 4 groups, using the linseed oil added, marigold extract added, and yeast selenium added diets to produce normal, n-3 fatty acid-enriched, lutein-enriched and selenium-enriched eggs by feeding for 28 d, determined the eggs’ nutrient content and egg quality. The results showed that the n-3 fatty acid, lutein and selenium contents of the eggs of dwarf layers were significantly increased by changing the diets and did not affect the egg weight, eggshell strength, Haugh units or the proportion of egg parts. The results of this study are helpful to understand the trend of egg consumption preferences in China, and on this basis to produce functional eggs that meet the consumers’ expectations.

Thermal pasteurization of shell eggs, at various time-temperature combinations, has been proposed previously and implemented industrially. This study was conducted to determine if shell egg heating rate, which varies with different pasteurization implementations, alters the Salmonella enterica serovar Enteritidis response to different stresses or expression of virulence. Shell eggs, containing Salmonella Enteritidis in yolk, were subjected to a low (2.4°C/min) or a high (3.5°C/min) heating rate during treatments that mimicked the pasteurization temperature come-up stage. The low heating rate protected Salmonella from the following processes: (i) lethal heat at the holding stage, (ii) loss of viability during 8-h cooling after heating, and (iii) sequential antimicrobial ozone treatment. Transcriptional analysis using Salmonella reporter strains revealed that the heat stress response gene grpE was transcribed at 3-fold-higher levels (P = 0.0009) at the low than at the high heating rate. Slow heating also significantly increased the transcription of the Salmonella virulence-related genes sopB (P = 0.0012) and sseA (P = 0.0006) in comparison to fast heating. Salmonella virulence was determined experimentally as 50% lethal dose (LD50) values in an in vivo model. The slow heat treatment mildly increased Salmonella Enteritidis virulence in mice (LD50 of 3.3 log CFU), compared to that in nontreated yolk (LD50 of 3.9 log CFU). However, when ozone application followed the slow heat treatment, Salmonella virulence decreased (LD50 of 4.2 log CFU) compared to that for heat-treated or nontreated yolk. In conclusion, heating shell eggs at a low rate can trigger hazardous responses that may compromise the safety of the final pasteurized products but following the thermal treatment with ozone application may help alleviate these concerns. [ABSTRACT FROM AUTHOR]

In the United States, all shell eggs processed under the USDA Agricultural Marketing Service voluntary grading standards must receive a shell sanitizing rinse of 100–200 ppm chlorine or its equivalent after leaving the washing process. A study was conducted to determine the concentration of peroxyacetic acid (PAA) which would be equivalent to 100–200 ppm chlorine (Cl) in reducing target organisms under the required washing conditions for shell eggs. Three isolates of Salmonella spp. (Enteritidis, Braenderup, and Typhimurium), as well as Enterobacter cloacae were used as inocula. Sanitizing treatments were negative control; deionized water; 100 and 200 ppm Cl; and 50–500 ppm PAA (7 concentrations). Considering all isolates tested, 100 and 200 ppm chlorine had 2.6 and 2.3 log cfu/mL cultural organisms remaining on shell surface; 50 and 100 ppm peracetic acid had 1.9 and 1.0 log cfu/mL cultural organisms remaining, respectively, compared with untreated control average of 3.8 log cfu/mL (P 250 ppm did not produce significant reductions in microbial populations as PAA concentration increased. Culturing for the prevalence of viable and injured organisms, 400–500 ppm PAA resulted in fewer eggs (P

Egg safety and quality is a long-standing concern for producers and consumers. Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) is the prevalent egg-product-related foodborne pathogen. The treatment with organic acids, including lactic acid, for the elimination and control of foodborne pathogens is generally recognized as safe, and is widely applied in many foods. In this study, we found that spraying with 2% lactic acid on the eggshell surface effectively reduced Salmonella Enteritidis counts. Agar-filled eggs were used to study the bacterial penetration of the eggshell (eggshell and membranes), and the contamination of the whole egg contents was investigated. No significant differences were observed between the Salmonella Enteritidis penetration in lactic acid sprayed and unsprayed eggs stored at 4 °C. The Haugh unit, albumin pH, and eggshell strength values were similar in the sprayed and washed eggs. Average Haugh unit scores for sprayed eggs were still Grade A within 3 weeks. However, the lactic acid treatment decreased the eggshell strength and cuticle layer thickness. SEM observations confirmed that spraying of lactic acid damaged the cuticle integrity. The results from our research will indicate that lactic acid spray is highly effective in reducing Salmonella contamination on the eggshell surface, but trans-shell penetration was demonstrated in the eggs stored at room temperature. Consequently, low-temperature storage is important for the prevention of recontamination of the egg after spraying. • Spraying with lactic acid on the eggshell surface effectively reduced Salmonella Enteritidis contamination. • No significant effect of lactic acid spraying was recorded on Salmonella Enteritidis penetration at 4 °C. • Salmonella penetration was correlated with the coverage of cuticle layer. • Low-temperature storage is effective at inhibiting SE recontamination of the egg after spraying. [ABSTRACT FROM AUTHOR]

Summary: The existing radio frequency (RF) shell egg pasteurisation method, while 60% faster than the industrial hot water method, requires manual rotation of the eggs and expensive deionised water. Therefore, the RF pasteurisation equipment was redesigned to automate egg rotation and use inexpensive tap water. A two‐step process heated eggs for 6 min with RF and then for 15 min with 56.7 °C water. The 21‐min combination process reduced Salmonella Typhimurium in eggs by 6.1 log without affecting the appearance of the albumen, whereas processing with 56.7 °C water alone required 60 min to reduce Salmonella by 5.0 log and clouded the albumen. Angel food cakes made from 21 min RF eggs had significantly greater volumes (P < 0.0001) than those from 60‐min hot water eggs. The improved RF process produced better eggs and cakes than those from the industrial hot water process and is now commercially feasible. The radio frequency (RF) pasteurisation process was improved by automating it and reducing its cost. Using the new RF equipment, Salmonella in shell eggs was reduced by 99.9999% in 21 min which is approximately one‐third the time of the existing industrial pasteurisation process. RF pasteurisation maintained the fresh appearance of egg whites and produced significantly better angel food cakes compared to those from the industrial process. [ABSTRACT FROM AUTHOR]

Egg is a regularly consumed food item. Currently, chlorinated water washing is the most common practice used to disinfect eggs, but this process has a negative environmental impact. A new physical technique, plasma-activated water (PAW), has been demonstrated to possess effective antibacterial activities without long-term chemical residue. In this study, air PAW was used to inactivate Salmonella enterica serovar Enteritidis on shell eggs. Different combinations of activation parameters, including water sources (reverse osmotic (RO) water, tap water), power (40 W, 50 W, 60 W) and activation time (10 min, 20 min, 30 min), were evaluated. The oxidation−reduction potential (ORP) and pH values of each combination were measured, and their antibacterial activity was tested in a bacterial suspension. Higher antibacterial activities, higher ORP values, and lower pH values were obtained with higher power, longer activation time, and lower water hardness. The antibacterial activities of PAW decreased rapidly by increasing the storage time both at room and refrigeration temperatures. Afterwards, RO water was pre-activated for 20 min at 60 W, and then the eggs inoculated with S. enteritidis were placed into PAW for 30 s, 60 s, 90 s, or 120 s with a plasma on-site treatment in the water. More than a 4 log reduction was obtained with 60-s and 120-s treatments. The results showed that the freshness indexes of the eggs treated with PAW were similar to those of the untreated controls and better than those of the eggs treated with commercial processes. In addition, observation under a scanning electron microscope also showed less surface damage of the cuticle on the PAW-treated eggs than on the commercially treated eggs. The results of this study indicate that PAW could be an effective antibacterial agent with less damage to the freshness of shell eggs than commercial methods.

Salmonella Enteritidis (SE) prevalence in eggs is a major concern to the egg industry. Some research has shown that egg sweating can increase Salmonella penetration into egg contents when refrigerated eggs are moved to a warmer temperature. This occurs when eggs are tempered before wash, to minimize thermal cracks. The effect of egg sweating on SE penetration into shell eggs over a 6 week storage period at 4°C was assessed. A 2 × 2 factorial of SE inoculation and egg sweating was utilized. Treatments included (SES) nalidixic acid (NA)-resistant SE inoculated and sweated, (SENS) NA-resistant SE inoculated and not sweated, (NSES) buffered peptone water (BPW) inoculated and sweated, and (NSENS) BPW inoculated and not sweated. Eggs were inoculated with 108 SE. Eggs formed condensation for approximately 17 min in a 32°C incubator. Shell rinse, shell emulsion, and egg contents were sampled then enumerated and assessed for prevalence of SE over a 6 wk storage period at 4°C. After wk 1, the SENS shell rinse had higher SE counts (0.32 log10 CFU/mL) than the other 3 treatments, where no SE was enumerated. A significant week by treatment interaction was found for the shell rinse SE detection (P < 0.05). In subsequent weeks, no SE counts were obtained from the egg shell rinse, shell emulsion, or egg contents. The SENS shell rinses had significantly higher SE prevalence than the SES rinses in weeks 1 (100% vs. 34.3%), 2 (57.6% vs. 22.2%), and 3 (38.2% vs. 11.1%) (P < 0.05). In samples from weeks 4, 5, and 6, there was no difference in SE prevalence between SES and SENS. Egg sweating did not increase SE penetration into the shell emulsion across treatment or week (P < 0.05). The decreasing trend of SE prevalence obtained over the study period indicate that refrigeration is effective at inhibiting SE growth. These results indicate that egg sweating occurring under common US egg handling practices is not harmful to egg safety. [ABSTRACT FROM AUTHOR]

The interior of the eggs obtained from healthy hens might be accepted to be free of microorganisms while the outer shell surface might include various microorganisms including pathogens. These microorganisms might pass through micro-cracks in the shell, or egg constituents might be contaminated while the shells are broken by accident or for process related purposes. These cause high microbial risk. Various surface decontamination techniques for shell eggs are applied, and thermal techniques have a certain limitation not to affect the functional properties of egg constituents especially egg white. Infrared application for surface decontamination is one suggested industrial application, and like all the other thermal methods, surface temperature of the shell should not exceed a certain value and must be determined in a quick and accurate manner. Thermocouple measurements bring certain difficulty for surface temperature determination. Hence, use of more convenient methods is required. Therefore, in this study, an infrared thermography method was improved for surface temperature measurement of the eggs undergoing an infrared surface decontamination process. [ABSTRACT FROM AUTHOR]

Hedonic modeling and retail scanner data were utilized to investigate the influence of local, organic, nutrition benefits, and other attributes of shell eggs on retail price premium in Hawaii. Within a revealed preference framework, the analysis of local and organic attributes, simultaneously, under a single unified setting is important, as such work is highly deficient in the published literature. This paper finds high to moderate price premiums in four key attributes of shell eggs -- organic (64%), local (40%), nutrition benefits claimed (33%), and brown shell (18.4%). Large and extra-large sized eggs also experience price premiums over medium sized eggs. With each larger packing size, the estimated coefficients were negative, indicating a price discount, relative to the baseline packing size. However, there is no evidence to support the overwhelming influence of "local" over "organic", as hypothesized in other research work. Overall, the findings in this paper suggest industry producers and retailers should highlight and market effusively the primary attributes of their shell eggs, including "local", to remain competitive in the marketplace. Effective communication channels are crucial to delivering the product information, capturing the attention of consumers, and securing retail sales. [ABSTRACT FROM AUTHOR]

Salmonella is a zoonotic pathogen commonly transmitted through food. External disinfection of shell eggs is of crucial importance to health in reducing egg-borne salmonellosis, since Salmonella on the shells can be easily transmitted to other food products or infect food handlers. A new thermal treatment was developed for the inactivation of Salmonella enterica on shell eggs. Steam is applied to the eggs while they move through a Thermal Trap (TT)- a partially enclosed chamber filled with steam. Following parameter optimization, a short treatment of a few seconds in a TT prototype completely inactivated Salmonella (>7.8 log CFU reduction) on artificially-inoculated fresh shell eggs. The treatment had no adverse effects on Haugh units, albumen and yolk pH, and albumen whip. The technology is efficient in terms of energy and operation and may provide a feasible solution for shell egg external disinfection. • Shell eggs were treated for external disinfection. • A new method for efficient thermal treatment was applied. • Complete eradication of Salmonella was achieved by seconds of exposure to steam. • No adverse effects on egg quality were found. [ABSTRACT FROM AUTHOR]

This study investigated the bactericidal effect of low-energy X-ray on mono-culture biofilms of Salmonella Enteritidis and Pseudomonas fluorescens biofilm as well as co-culture biofilms of S. Enteritidis and P. fluorescens at the ratio of 1:1 and 1:100 (S. Enteritidis: P. fluorescens) on shell eggs. The results showed that the low-energy X-ray irradiation could effectively inactivate the mono-culture biofilm cells of S. Enteritidis and P. fluorescens with the t R values of 63.19 Gy and 66.53 Gy, respectively. The low-energy X-ray irradiation could also effectively inactivate co-culture biofilm cells with t R values of 80.03 Gy and 47.97 Gy for S. Enteritidis biofilm cells in the 1:1 and 1:100 ratios of co-culture, respectively, and 61.87 Gy and 30.16 Gy for P. fluorescens biofilm cells in the two ratios of co-co-culture, respectively. Apart from inactivating biofilm cells, extracellular polysaccharide (EPS) was markedly reduced at increasing dosage of irradiation. Based on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and texture profile analysis (TPA) results, egg white proteins and the puncture force of eggshell remained unchanged after the irradiation at up to 225 Gy. No 2-alkylcyclobutanones (2-ACBs) were detected in the irradiated eggs. These findings demonstrated that low-energy X-ray has potential as an effective method to inactivate the mono- and co-culture biofilms of S. Enteritidis and P. fluorescens on shell eggs. • Low energy X-ray showed high sterilization efficacy on egg shell. • Mono/co-culture S. Enteritidis biofilm cells were inactivated by 5 log at 175–225 Gy. • Low-energy X-ray caused destruction of extracellular polysaccharide. • No 2-alkylcyclobutanones (2-ACBs) were detected in irradiated egg. • Irradiation did not change egg white proteins and egg shell puncture force. [ABSTRACT FROM AUTHOR]

The current approaches remain insufficient for measuring chicken egg spoilage or present analytical limitations. This study aimed to complement the existing analyses and identify novel markers using liquid chromatography-high resolution mass spectrometry-based foodomics strategies. In the discovery set, comparative untargeted metabolomics was utilized to identify marker candidates in microbially inoculated chicken eggs. Markers were annotated by spectral matching with authentic standards, experimental libraries, or in silico fragmentation. In the validation set, targeted metabolomics was employed to verify the markers in stored chicken eggs from five farms. Statistical differences at a p -value < 0.001 revealed increases in lactic and 3-hydroxybutyric acids and decreases in phosphocholine, LPE(O-18:1), LPC(16:0), and LPC(18:0) in stored eggs. Receiver operating characteristic curve analysis of the six combined markers yielded an AUC of 0.956 and a sensitivity and specificity of ∼90%. Four phospholipids were highlighted as a novel class of spoilage markers. Our findings may contribute to further industrial implementation, benefiting the quality assurance and food safety of poultry egg production.

The objective of this work was to computationally investigate radio frequency (RF) heating rate and uniformity of shell egg as affected by orientation and rotation. To do this, a multiphysics model was developed using COMSOL to simulate RF heating of a vertically oriented non-rotating shell egg. This model was experimentally validated against temperature measurements taken at three different internal locations within the egg. Simulations were then performed using the validated model with both non-rotating and rotating egg for different orientations (vertical and horizontal). Rotation of egg was incorporated into the model by rotating the RF system around the stationary egg instead of rotating the egg. Temperature-dependent material properties of the yolk, albumen and shell within a temperature range of 20 to 70 °C were used in the model. Simulated temperature uniformity index (STUI) values were calculated to evaluate the effect of orientation and rotation on heating uniformity. The results showed that heating was more uniform when shell egg was oriented horizontally rather than vertically. However, rotation did not further improve heating uniformity of the horizontally-oriented egg. Although heating uniformity was improved when the vertically-oriented egg was rotated, concentrated heating around the air cell could not be avoided. • Radio frequency heating uniformity of vertically-oriented shell egg was highly non-uniform, even when it was rotated. • Shell egg heated much more uniformly, but more slowly, in the horizontal orientation. • Rotation did not improve heating uniformity of the horizontally-oriented shell egg placed in the middle of the electrodes. • A rapid and relatively uniform heating may be achieved if shell egg is horizontally oriented and rotated near the electrodes. [ABSTRACT FROM AUTHOR]

Egg is a regularly consumed food item. Currently, chlorinated water washing is the most common practice used to disinfect eggs, but this process has a negative environmental impact. A new physical technique, plasma-activated water (PAW), has been demonstrated to possess effective antibacterial activities without long-term chemical residue. In this study, air PAW was used to inactivate Salmonella enterica serovar Enteritidis on shell eggs. Different combinations of activation parameters, including water sources (reverse osmotic (RO) water, tap water), power (40 W, 50 W, 60 W) and activation time (10 min, 20 min, 30 min), were evaluated. The oxidation–reduction potential (ORP) and pH values of each combination were measured, and their antibacterial activity was tested in a bacterial suspension. Higher antibacterial activities, higher ORP values, and lower pH values were obtained with higher power, longer activation time, and lower water hardness. The antibacterial activities of PAW decreased rapidly by increasing the storage time both at room and refrigeration temperatures. Afterwards, RO water was pre-activated for 20 min at 60 W, and then the eggs inoculated with S. enteritidis were placed into PAW for 30 s, 60 s, 90 s, or 120 s with a plasma on-site treatment in the water. More than a 4 log reduction was obtained with 60-s and 120-s treatments. The results showed that the freshness indexes of the eggs treated with PAW were similar to those of the untreated controls and better than those of the eggs treated with commercial processes. In addition, observation under a scanning electron microscope also showed less surface damage of the cuticle on the PAW-treated eggs than on the commercially treated eggs. The results of this study indicate that PAW could be an effective antibacterial agent with less damage to the freshness of shell eggs than commercial methods. [ABSTRACT FROM AUTHOR]

The current study was conducted to evaluate the ability to recover Salmonella from shell egg contents by culture methods. A total of 4,000 eggs were obtained from a grading and packing center located in the Gyeonggi Province of South Korea, and 200 samples were created by pooling 20 broken eggs. The pooled samples were held at room temperature for 4 d before a 25-mL aliquot of each pool was added to 225 mL of modified trypticase soy broth (mTSB) and incubated at 35°C for 24 ± 2 h. A loopful of the culture was streaked onto chromogenic Druggan-Forsythe-Iversen (DFI) agar and incubated at 36 ± 1°C for 18-24 h. In addition, 1 mL and/or 0.1 mL of the mTSB cultures were added to 10 mL of Muller-Kauffmann tetrathionate with novobiocin (MKTTn) or Rappaport-Vassiliadis (RV) broth, and they were incubated for 24 ± 2 h at 35 ± 2°C or 42 ± 0.2°C, respectively. A loopful from these cultures was streaked onto Brilliant Green (BG), xylose lysine deoxycholate (XLD), and bismuth sulfite (BS) agar plates, respectively. Directly streaking onto DFI agar revealed the presence of Salmonella in 14 out of the 200 pooled samples (7%); whereas the combination of RV medium and BG, XLD, and BS agar detected the pathogen in only 9 (4.5%), 7 (3.5%), and 3 (1.5%) of the pooled samples, respectively. When MKTTn broth was used, Salmonella was detected in 7 (3.5%), 2 (1%), and 0 (0%) of the samples when streaked onto BG, XLD, and BS agar, respectively. The results indicate that direct plating onto DFI agar without enrichment was the most suitable among the methods evaluated in this study for detecting Salmonella in raw shell egg contents with a low microbial load.