Liquid Egg Research Articles

Development and Evaluation of Egg Processing Machine for Poached Eggs Production

This study was carried out to develop and evaluate an egg processing machine for poached eggs. The parts of the machine include the hopper, conveyor screw, the main housing, shell outlet, liquid egg outlet, motor, belt, pulley and cooking section. Materials for construction of the machine were carefully selected by balancing availability, durability, resistance to corrosion, suitability for food contact application with cost. The machine was evaluated in terms of throughput and material capacities and the values obtained were 301.14 kg/h and 548.4 kg/h respectively. Proximate compositions of the raw and poached eggs were 0.655%, 10.751%, 6.722% and 0.569%, 9.849%, 6.344% for ash, protein and fat contents respectively. It can be deduced that there was no reduction in the quality of the poached eggs as compared to the raw eggs.

Viscoelastic and Viscoplastic Glucose Theory (VGT #30): Applying VGT with two Different CGM Sensor Measured 3-Hour Postprandial Plasma Glucose (PPG) Values from 240 Liquid Egg Meals and 191 Solid Egg Meals as the Strain, Along with the PPG Change Rate Multiplied by a Viscosity Factor of Average Carbs/Sugar Amounts for Each Egg Meal Type as the Stress, and then Applying

The author has studied strength of materials and theory of elasticity through his undergraduate courses at the University of Iowa. He also conducted research work on UI campus to earn a master’s degree in Biomechanics under Professor James Andrews. At that time, he used a combined spring and dashpot model to simulate the behaviors of human joints, bones, muscles, and tendons in order to investigate the human-weapon interactions during the Vietnam war era. Later, he went to MIT to pursue his PhD study under Professor Norman Jones, who taught him theory of plasticity and dynamic plastic behaviors of various structure elements. He also took additional graduate courses in the field of fluid dynamics and thermodynamics along the way of his schooling years. Since then, many advancements have been made in the biomechanics branch, especially with human body tissues that possess certain viscoelastic characteristics, such as bones, muscles, cartilages, tendons (connect bone to muscle), ligaments (connect bone to bone), fascia, and skin. For example, the author suffered plantar fasciitis for many years. He understood that the night splint dorsiflexes forefoot, at the back of the foot, increases plantar fascia tension to offer stress-relief for the pain. This model where muscles and tendons connect the lower leg and foot is a form of viscoelastic study for medical problem solving. When dealing with human internal organs, it is not easy to conduct live experiments to obtain accurate measurements for the biomedical material properties. Blood itself is a viscous material (time-dependent) and its viscosity factor may fall between water, honey, syrup, or gel. The author’s research focuses on “glucose” where the blood sugar amount is produced by the liver and carried by red blood cells, not the blood itself. The postprandial plasma glucose (PPG) is strongly influenced by both energy input via carbs/sugar intake amount (~60%) and energy output via post-meal exercise level (~40%). Fundamentally, the PPG level is also dependent on the individual’s health conditions in regard to liver cells and pancreatic beta cells, which produce glucose and release insulin to control the glucose level in blood. Therefore, it is nearly impossible to measure the material geometry or material properties to determine the viscosity of “glucose” like in engineering research work. As a result, the best the author could do is to apply the “concept” of viscoelasticity and/or viscoplasticity” to construct an analogy model of time-dependent glucose behaviors.

Viscoelastic and Viscoplastic Glucose Theory (VGT #31): Applying VGT with Two Different CGM Sensor Measured 2-Hour Postprandial Plasma Glucose (PPG) Values from 240 Liquid Egg Meals and 191 Solid Egg Meals as the Strain, Along with the PPG Change Rate Multiplied by a Viscosity Factor of Average Carbs/Sugar Amounts for Each Egg Meal Type as the Stress, and then Applying

The author has studied strength of materials and theory of elasticity through his undergraduate courses at the University of Iowa. He also conducted research work and earned a master’s degree in Biomechanics under Professor James Andrews. In 1970-1971, he used a combined spring and dashpot model to simulate the behaviors of human joints, bones, muscles, and tendons in order to investigate the human-weapon interactions during the Vietnam war era. Later, he went to MIT to pursue his PhD study under Professor Norman Jones, who taught him theory of plasticity and dynamic plastic behaviors of various structure elements. To further his education, he took additional graduate courses in various fields of fluid dynamics, thermodynamics, bridge design using energy absorption pad, and soil mechanics under earthquake influences which have dealt with “time-dependency” issues. Since then, many advancements have been made in the biomechanics branch, especially with human body live tissues that possess certain viscoelastic characteristics, such as bones, muscles, cartilages, tendons (connect bone to muscle), ligaments (connect bone to bone), fascia, and skin. For example, the author suffered plantar fasciitis for many years. He understood that the night splint dorsiflexes forefoot, at the back of the foot, increases plantar fascia tension to offer stress-relief for the pain. This model where muscles and tendons connect the lower leg and foot is a form of viscoelastic study for medical problem solving. When dealing with human internal organs, it is not easy to conduct live experiments to obtain accurate measurements for the biomedical material properties. Blood itself is a viscous material (time-dependent) and its viscosity factor may fall between water, honey, syrup, or gel. But, the author’s research focus is on “glucose” where the blood sugar amount is produced by the liver and carried by red blood cells, not the blood itself. The postprandial plasma glucose (PPG) is strongly influenced by both energy input via carbs/sugar intake amount (~60%) and energy output via post-meal exercise level (~40%). Fundamentally, the PPG level is also dependent on the individual’s health conditions in regard to liver cells and pancreatic beta cells, which produce glucose and release insulin to control the glucose level in blood. Therefore, it is nearly impossible to measure the material geometry or material properties to determine the viscosity of “glucose” like in engineering research work. As a result, the best the author could do is to apply the “concept” of viscoelasticity and/or viscoplasticity” to construct an analogy model of time-dependent glucose behaviors.

The Quality Analysis and Deterioration Mechanism of Liquid Egg White during Storage

The quality of liquid egg white (LEW) during storage is critical for the development of the egg industry. In order to effectively control its storage quality, the effects of packaging materials and storage conditions on the quality of LEW were investigated. High-throughput sequencing (HTS) was applied to explore changes in bacterial population proportions and microflora in the spoilage of LEW. The shelf life of LEW packaged with glass (LEW-PG), plastic (LEW-PP), and tinplate (LEW-PT) was preliminarily determined to be 8, 5, and 7 days, respectively. LEW-PG possessed superior sensory scores (65) and L values (87.5), and a lower growth rate of total volatile basic nitrogen (TVB-N) content among the three samples on the last day of shelf life, and was chosen for further study. During 24 days of storage, the sensory scores of the LEW-PG in 10 °C and 4 °C groups decreased by 32.7% and 25.7%, respectively. There was no significant difference in foaming properties of LEW-PG between the 10 °C and 4 °C groups (p > 0.05). HTS analysis showed that the abundance of species composition in the 10 °C samples was higher than that in the 4 °C samples, though the latter possessed a higher community diversity. At the genus level, the dominant bacteria in the 10 °C group were Pseudomonas (21.79%), others (19.21%), and Escherichia (11.21%), while others (37.5%), Escherichia (30.40%), and Bifidobacterium (17.72%) were highly abundant in the 4 °C samples. It is hoped that this study could provide theoretical support for quality control of LEW during storage.

Relationship between iron bioavailability and Salmonella Typhimurium fitness in raw and pasteurized liquid whole egg

SalmonellaEnteritidis growth rates in liquid whole egg have been shown to be dependent on the initial inoculum dose and on the egg product's thermal history. This study's objective is to obtain further insight into the mechanisms underlying both phenomena. First we verified that Salmonella Typhimurium ATCC 14028s cells displayed the behavior already described for S. Enteritidis cells. Then, we carried out supplementation assays by adding different concentrations of egg-white antimicrobial proteins, iron, or siderophores to the egg samples (raw or pasteurized liquid whole egg, depending on the assay). These experiments revealed that addition of lysozyme (at the concentration at which it is present in liquid whole egg) did not affect Salmonella growth in pasteurized liquid whole egg, but that ovotransferrin as well as Ex-FABP caused a significant (p < 0.05) reduction in Salmonella growth rates in whole egg pasteurized at 70 °C for 1.5 min. Furthermore, we observed that the inactivation of ovotransferrin was dependent on treatment intensity within the range studied. On the other hand, addition of iron or siderophores to raw or low temperature (60 °C/3.5 min) pasteurized liquid whole egg increased the growth rate of Salmonella cells inoculated at a low initial dose. The concentration of these supplements required to reach the growth rate of cells inoculated at a high dose was lower for pasteurized than for raw egg. Finally, growth of a set of deletion mutants in genes coding for proteins related to different iron uptake systems, along with supplementation assays using spent medium revealed the key role of salmochelin in growth of S. Typhimurium in raw whole egg. In summary, our results strongly suggest that iron bioavailability determines the fitness (growth rates) of Salmonella cells in liquid whole egg. Thus, the higher the intensity of the thermal treatment applied to liquid egg, the more iron would be available, a phenomenon that would be linked to the denaturation of iron and/or siderophore binding egg proteins. Further work is still required to fully elucidate why lower Salmonella initial doses lead to lower growth rates, but it can be hypothesized that this might be related to a lower amount of siderophores being released to the medium (especially salmochelin), which would also limit iron bioavailability.

Effects of guar gum or xanthan gum addition in conjunction with pasteurization on liquid egg white

In this study, effects of varying levels of xanthan or guar gum (XG/GG, 0.05%, 0.1%, 0.2%, 0.4% and 0.8%, w/v) on the spatial structure and functional properties of egg white (EW) proteins under different pasteurization conditions of the liquid egg was evaluated. Results showed that XG could bury the aromatic ring residues and reduce the hydrophobicity of protein in EW, whereas GG could only increase the hydrophobicity. With 0.8% GG addition and pasteurization under 60℃/3.5 min, the emulsifying stability of EW was improved by nearly 100%, while with 0.8% XG addition the gel structure of EWwould become porousandloosen under each pasteurization condition. The hardness of EW gels was decreased by 90% when the concentration of XG was 0.4% or 0.8%. According to the results, the concentration of gums and the pasteurization parameters should be considered together when adding gums into the liquid egg products for pasteurization simultaneously.

Improvement of Structural Characteristics for Liquid Egg White by Enzyme Treatment

ABSTRACT In this study, the functionality of liquid egg albumin pre-treated by protease was investigated to evaluate the storage stability mechanisms for field of gastronomy and gastronomist. This study aims to improve the physicochemical and functional properties such as relative whipping capacity (RWC), foam stability, color, pH, and turbidity by protease (0-control, 0.5, 1.0, and 1.5%-v/v). The protease enhanced RWC comparing to the untreated on day-0 and 27, while the control group showed lower RWC and higher values in 1% and 1.5% treatments. The effect of protease was more clearly apparent on turbidity with significantly decrease during storage (p < .05). The turbidity values ranged from 0.74 to –0.31. A considerable decrease was observed in color values of treated samples on day 27, while the best treatment was 1.0% in foam stability and 1.5% in RWC. Protease could be used in modified albumin to improve techno-functional characteristics of bakery products.

Effect of Biodegradable Packaging on the Shelf-Life of Pasteurised Whole Egg Mass

Abstract The aim of this study was to determine the effect of two types of packaging on the change in quality indicators of pasteurised liquid egg mass. Traditionally, the shelf-life of pasteurised liquid egg mass is up to 28 days. The increase in shelf-life would increase the exportation options of this product. The liquid egg mass was pasteurised on the equipment Ovobel AR56SH; the pasteurisation process continued for 60 minutes, reaching a maximum temperature from 65 °C to 68 °C (hold time: 360 seconds). This paper focuses on two main packaging materials: high-density polyethylene (HDPE) and Tetra Rex® Bio-based. Forty-two samples of each packaging material were used to study the contents. Changes in the quality of samples during storage were estimated by measuring the total bacterial count (CFU/g) from 200 at the start of shelf-life up to 30×105 units (LVS ISO 4833-1:2014). Data in the test was explored with Anova: Single Factor statistical model and correlation method. Data that was obtained emphasises the importance of packaging type, which could provide stable quality of ready-to-use products for a duration of up to forty-five days.

MEMPELAJARI JANGKA WAKTU BLANSING DENGAN UAP AIR TERHADAP BEBERAPA KARAKTERISTIK TEPUNG TELUR

Egg flour is one form of egg preservation through the process of drying and curing. Besides being more durable, another advantage of egg flour is that the volume of the material becomes much smaller so that it saves storage and transportation space. chemical, quality degradation (Buckle, Edward, Fleet and Wotton, 1987). One of the obstacles in the manufacture of egg flour is the occurrence of the browning process in egg flour. This browning process occurs due to the presence of glucose in the liquid egg which reacts with the amino groups of the protein. The purpose of this study was to determine the appropriate period of blanching with water vapor, in order to obtain some characteristics of good egg flour. The research will be carried out from March to April 2020 in Laboratory Food Technology at the Faculty of Agriculture Ma’soem University, Bandung City. The experimental method used in this study is an experimental method using a Randomized Block Design. Each treatment consisted of 5 treatments and each treatment was repeated 5 times. These factors: blanching period of 1 minute, 3 minutes, 5 minutes, 7 minutes and 9 minutes. The results showed that the blanching period with steam for 3 minutes produced good characteristics. This determination was based on chemical analysis of the water content of egg flour (2.75%), protein content (49.97%) and fat content (35.83%) and organoleptic assessment of color ( 3.40), Aroma (4.30) and Texture of egg flour (2.68)

Determination of Selenomethionine, Selenocystine, and Methylselenocysteine in Egg Sample by High Performance Liquid Chromatography—Inductively Coupled Plasma Mass Spectrometry

The deficiency of selenium in dietary is recognized as a global problem. Eggs, as one of the most widely consumed food products, were readily enriched with selenium and became an important intake source of selenium for humans. In order to better understand the speciation and bioaccessibility of selenium in eggs, a simple and reliable approach that could be easily used in a routine laboratory was attempted to develop for analyzing selenium species. Three of organic selenium species (selenocystine, methylselenocysteine, and selenomethionine) in liquid whole egg were completely released by enzymatic hydrolysis and detected by high performance liquid chromatography in combination with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). All the parameters in enzymatic hydrolysis and separation procedures were optimized. The effect of matrix in analysis was critically evaluated by standard addition calibrations and external calibrations. Under the optimal conditions, the spike recoveries of selenium species at 0.1–0.4 μg g−1 spike levels all exceeded 80%. This method was successfully applied to the determination of selenium species in fresh egg and cooked eggs.

Structural and rheological properties of mung bean protein emulsion as a liquid egg substitute: The effect of pH shifting and calcium

The objective of this study was to develop functional egg substitutes using mung bean protein (MBP) through pH12-shifting modification and calcium addition. The influence of pH12-shifting and Ca2+ ions on emulsion stability and the physical properties of MBP-based emulsion gels were elucidated in a neutral (pH 7) composite system (7.2% MBP and 10% canola oil). Results showed that the pH12-treated MBP emulsions were stable even after 5-day storage at 25 °C. The pH12-shifting significantly decreased the average emulsion droplet size from 524 nm in emulsion of native MBP to 422 nm. The emulsion samples were further heated at 95 °C to induce the formation of gels. With the calcium addition of 0 or 5 mM, the pH12 MBP emulsion did not form self-supporting gels. In the presence of 10–20 mM Ca2+, emulsion gels prepared with pH12-treated MBP exhibited a uniform and compact network structure. The gel hardness, water-holding capacity, and water distribution of pH12-treated MBP emulsion gels were superior to that of the native MBP samples. This study demonstrated MBP-based emulsion gels can be improved by pH12-shifting treatment in combination with calcium addition, resulting in a similar texture to egg, hence, the potential to develop MBP-based egg substitutes.

Rheological and Flow Behaviour of Yolk, Albumen and Liquid Whole Egg from Eggs of Six Different Poultry Species.

Liquid egg products are one of the basic raw materials for the food industry. Knowledge of their rheological and flow behaviour in real technical elements is absolutely necessary for the selection of suitable technological equipment for their processing. In this article, the rheological properties of liquid egg products were determined. Eggs from six different species of poultry are used: domestic hen (Gallus gallus domesticus) hybrid Hisex Brown; Japanese quail (Coturnix japonica); German carrier goose (Anser anser f. domestica); domestic ducks (Anas platyrhynchos f. domestica); domestic guinea fowl (Numida meleagris f. domestica); and domestic turkeys (Meleagris gallopavo f. domestica). Liquid egg products showed pseudoplastic behaviour in range of shear strain rates from 0.2 up to 200 s−1 and at the temperature of 18 °C. Thus, the flow curves were constructed using the Ostwald-de Waele rheological model, with respect to the pseudoplastic behaviour of liquid egg products. According to the values of the coefficients of determination (R2), the sum of squared estimate of errors (SSE) and the root mean square error (RMSE), this model was appropriately chosen. Using the consistency coefficient K, the flow index n and the adjusted equations for the flow rate of technical and biological fluids in standard pipelines, the 3D velocity profiles of liquid egg products were successfully modelled. The values of the Reynolds number of the individual liquid egg products were calculated, and the type of flow was also determined. A turbulent flow has been detected for some liquid egg products.

The manufacturing of lactobacillus microcapsules by freezing with egg yolk: The analysis of microstructure and the preservation effect against freezing and acid treatments

Encapsulation is an effective strategy to prevent probiotics from environmental damages. The survivability of Lactobacillus is generally reduced under frozen or acid environments. In this study, an attempt was made to encapsulate Lactobacillus into the egg yolk aggregates formed upon freezing. Lactobacillus broth was mixed with liquid egg yolk and frozen at selected temperatures and time periods. After thawing, the number of surviving bacteria was determined. The results showed that freezing with the addition of egg yolk improved Lactobacillus survivability. It was confirmed that freezing increased the number of egg yolk aggregates, and those aggregates coated Lactobacillus after freezing. The encapsulated Lactobacillus was treated at pH 2.5 for 10 min, and the results showed that the encapsulation process increased the acid resistance of Lactobacillus . These results indicate that freezing-induced encapsulation with egg yolk could effectively protect Lactobacillus against freezing and acid treatment. This finding could be useful for the design and preservation of probiotics-based food products. • Lactobacillus was encapsulated by freeze-induced aggregation of egg-yolk. • The present microencapsulation technique improved the survivability of lactobacillus. • Acid tolerance of lactobacillus was enhanced by the present encapsulation method. • The number concentration of egg-yolk aggregates increased under frozen environment. • Aggregate formation would correlate to the microencapsulation efficiency.

Sensory Studies on Snacks and Dips Elaborated with Lionfish Surimi

ABSTRACT Lionfish (Pterois volitans) have proliferated over the Caribbean Sea causing massive damage to coral reefs ecosystems. The development of products using lionfish is a control strategy that aims to decrease the negative impact of this species. In this research, the lionfish was processed to obtain surimi with a different set of binders (liquid egg white and starch) and high-power ultrasound. The surimi was used to elaborate two novel products: snacks and dipping sauce. A sensory panel was organized to determine the culinary applications with the highest appeal. The most liked fish snacks were obtained with ultrasound: (1) without binders and (2) with starch (3%). In case of dipping sauce, the most liked one was made by conventional method and egg white (1.5%). The use of ultrasound to obtain lionfish surimi in combination with binders demonstrated its potential to be used in the preparation of novel products with high sensory qualities.

To improve the gel properties of liquid whole egg by short-term lactic acid bacteria fermentation

Fermentation, as a simple, safe and environmentally friendly technology, is promising in the modification of proteins. In this study, the liquid whole egg (LWE) was fermented at 37 °C by Lactiplantibacillus plantarum 90 (L. plantarum 90) which the dose of inoculation was about 8 Log 10 CFU mL−1. During the process, the total aerobic mesophilic count (TAM) and the number of lactic acid bacteria (LAB) of LWE increased at 3 h and then decreased, consistent with the changes in protein solubility. Besides, the T2 relaxation time of fermented egg gels moved to low relaxation time (T22 shifted from 2154.44 ms (0 h) to 1232.85 ms (9 h)), indicating that the water retention of fermented egg gels was enhanced. After fermentation, it could be seen intuitively that the porous structure of the gel surface almost disappeared, along with the improved springiness and brightness by texture and color measurement. This study suggested that moderate fermentation (L. plantarum 90, 1% v/v, 9 h) could effectively improve the gel property of LWE, and thus had a potential to expand the application of LWE in the food industry.

Pengaruh Pemberian Pupuk Organik Cair Cangkang Telur Ayam Boiler dan Pupuk Anorganik Urea Terhadap Pertumbuhan dan Hasil Tanaman Bayam Merah (Amaranthus tricolor L.) Varietas Mira.

Red spinach is a vegetable plant that has high economic value and is usually consumed by the leaves. In 2019 there was a decrease caused by the lack of soil fertility so that to increase production, it could improve soil fertility by means of fertilization.The purpose of this study was to obtain the optimal combination dose of organic chicken eggshell fertilizer from inorganic urea fertilizer on the growth and yield of red spinach (Amaranthus tricolor L.) mira variety. The research was carried out from June to July 2021, on the exact land in Pasir jengkol Village, Majalaya District, Karawang Regency, West Java. The research method used was factorial randomized block design (RAK), the first factor was liquid organic fertilizer chicken egg shells (C) consisting of 3 levels: c0 (0 ml/L), c1 (30 ml/L), c2 (60 ml/L). L) and the second factor of inorganic fertilizer urea (u) consists of 3 levels: u0 (0 kg/ha), u1 (50 kg/ha), u2 (100 kg/ha).There were 9 treatments with 3 replications so there were 27 experimental units. The results showed that there was no interaction between the addition of liquid organic fertilizer chicken egg shells with inorganic fertilizers on the growth and yield of red spinach (Amaranthus tricolor L.) mira variety. There was no one dose of inorganic urea fertilizer that provided optimal growth and yield of red spinach (Amaranthus tricolor L.) mira variety for each dose of liquid organic fertilizer given chicken egg shells.

Validation of Modifications to the Soleris®E. coli Method for Detection and Threshold Determination of Escherichia coli in Select Foods: Level 3 Modification to AOAC Performance Tested MethodSM 101101.

Soleris®E. coli is an automated, growth-based method for detection and semi-quantitative determination of Escherichia coli in foods. The method can be used in dilute-to-specification (threshold) or presence/absence modes. The objective of the study was to validate four modifications to the method: (1) a change in the vial detection window plug composition from agar to agarose to improve plug consistency and robustness, (2) a change in pre-enrichment incubation time for presence/absence testing from 6 h to 18-24 h, (3) a change in vial incubation temperature from 44.5 to 43.5°C, and (4) incorporation of a simple direct-from-vial confirmation test as an alternative to traditional procedures. Elements of the study included inclusivity/exclusivity testing, matrix testing in comparison to the ISO 7251:2005 reference method, reagent stability/lot-to-lot consistency testing, and an independent laboratory study. In inclusivity testing, all 55 Escherichia coli strains tested produced positive results. In exclusivity testing, 30 of 31 strains of other bacterial species produced negative results, the sole exception being a strain of Enterobacter cloacae. In internal and independent laboratory matrix testing of mozzarella cheese, condensed milk, pasteurized liquid egg, and frozen green beans, results showed no significant differences in performance of the Soleris and reference methods with two exceptions, one in which the Soleris method produced more positive results, and one in which the reference method produced more positive results. Performance characteristics of the modified Soleris E. coli method are consistent with those of the original validated method. The Soleris E. coli method offers improvements in ease of use and reagent robustness.

Effect of different salt concentration on the physical properties of frozen thawed egg yolk

AbstractFreezing can enhance the storage time of liquid egg products, but egg yolk undergoes an irreversible textural and structural change when it is cooled to –6 °C. In this study, the effects of different salt concentrations on the physical properties of frozen-thawed egg yolk were investigated.The pasteurised liquid egg yolk (LEY) was treated with 4, 5, and 6% of NaCl before freezing and it was stored at –18 °C for 4 weeks. The colour, pH, and rheological characteristics (firmness, consistency, cohesiveness, and index of viscosity) of yolk samples were evaluated before and after freezing.Salt treatment resulted in preventing gelation, with decreasing firmness, consistency and viscosity compared to control samples. The pH of all yolk samples increased during frozen storage. The lightness value decreased in treated samples and increased in the control sample after freezing.The results indicated that the applied salt concentrations could inhibit protein aggregation of LEY induced by freezing during the storage period. At least 5% salt concentration could reduce effectively the changes in rheological properties.

In vitro efficiency evaluation of phage cocktail for biocontrol of Salmonella spp. in food products.

This study used a set of different bacteriophages to control contaminations of Salmonella spp., a major food pathogen. A cocktail of four phages designated based on host range and in vitro lytic assay showed a lower bacteriophage insensitive mutant frequency and considerable stability at 4°C and 28°C up to 60days. The work evaluated the effectiveness of cocktail of four phages in reducing Salmonella spp. in four different food matrices (liquid egg, eggshell, milk, lettuce). A maximum of 1.7 log reduction in Salmonella spp. was achieved upon treatment of liquid eggs with phage cocktail for 72h at 4°C. In milk, the application of phage cocktail reduced recoverable Salmonella spp. by 1.9 log and 1.8 log at 28ºC (6h) and 4ºC (72h), respectively. A significant 2.9 log reduction of Salmonella spp. was obtained in eggshell after a 6h incubation and Salmonella spp. was beyond detection level after 24h at 28ºC. The application of cocktail also reduced Salmonella spp. beyond the detectable level in lettuce after 8h at 28°C. Our results indicated considerable stability of phages in different food matrices. Taken together, our findings establish the potential effectiveness of the bacteriophage cocktail as a biocontrol agent for Salmonella spp. in different food matrices.

Characterization and Application of a Lytic Phage D10 against Multidrug-Resistant Salmonella

Salmonella is a widely distributed foodborne pathogen that is a serious threat to human health. The accelerated development of drug resistance and the increased demand for natural foods invoke new biocontrol agents to limit contamination by multidrug-resistant (MDR) Salmonella strains. In this study, a lytic Salmonella phage named D10 was characterized at the biological and genomic levels. D10 possesses a short latent period (10 min) and a large burst size (163 PFU/cell), as well as adequate stability under a range of pH conditions and moderate thermal tolerance. D10 effectively lysed different MDR Salmonella serovars and repressed their dynamic growth in the medium. Genomic analysis disclosed that D10 is a new member of the Siphoviridae family and lacks the genes implicated in lysogeny, pathogenicity, or antibiotic resistance. A three-ingredient phage cocktail was then developed by mixing D10 with previously identified myovirus D1-2 and podovirus Pu20. The cocktail significantly reduced the count of MDR strains in liquid eggs, regardless of the temperature applied (4 and 25 °C). These results suggest that phage D10 is a promising tool to prevent food contamination by MDR Salmonella.