Oxygen Permeable Film Research Articles

Storage and Packaging Effects on the Protein Oxidative Stability, Functional and Digestion Characteristics of Yak Rumen Smooth Muscle.

The objective of this study was to investigate the effects on protein oxidative stability, functional and digestion characteristics of yak rumen smooth muscle with overwrap packaging using oxygen-permeable film (OWP) and vacuum packaging bag (VP) during storage (0, 7, 14, 28, 42, 56, 84, 168 and 364 days) at −18 °C. The results show that yak rumen smooth muscle was oxidized with frozen storage through the formation of protein carbonyls and disulfide bonds, the loss of total sulfhydryl. The emulsifying activity of yak rumen smooth muscle protein (SMP) under VP began to perform a higher level than that under OWP after 14 days, and the foaming capacity under VP showed the highest level on the 28th day of 111.23%. The turbidity under VP reached the minimum 0.356 on the 28th day as well, followed by significantly increasing on the 56th day compared with OWP. The digestibility of yak rumen SMP under both OWP and VP reached the maximum on the 28th day of frozen storage. Moreover, yak rumen under VP at 28–56 days of frozen storage had good functional properties and high digestibility of SMP, which showed better edible value.

Retail display life extension of beef by gelatin-chitosan edible coating incorporated with allspice leaves extract

This study was aimed to examine the potential use of ethanolic allspice extracts as antioxidant agent on the edible gelatin-chitosan coating film to preserve the beef during retail display. Beef sirloins steaks were used in control (without edible coating), GEL (coating film) and AEXT (coating film containing 300 mg/kg of allspice extract) treatments, overwrapped in oxygen-permeable film and evaluated up to 10 days, in refrigeration (2.5°C). The effects and their interactions were analyzed using the F test (ANOVA) and, when statistically significant (P < 0.05), the means were compared using Duncan test. The psychrotrophic bacteria multiplication was not affected by treatments, but lactic acid bacteria growth was retarded in the coated meat samples. The edible coatings decreased weight losses and lipid oxidation of the meat compared to the control during storage, but the AEXT coating was most effective as an antioxidant. The coatings did not affect the myoglobin redox forms but increased the color stability, leading to samples with lighter (higher L* values) and bright red (higher h values) colors for up to 8-days against 6-days to control. However, these changes in instrumental color were considered small. The use of allspice extract on the edible coating film as an antioxidant is feasible, but more studies are needed to reach the ideal blend to reduce meat discoloration during display.

Feeding, Muscle and Packaging Effects on Lipid Oxidation and Color of Avileña Negra-Ibérica Beef.

Simple SummaryIn recent years, interest has grown in improving the productivity of pure local breeds in Spain using corn silage as an alternative to concentrates. The aim of this investigation was to evaluate the lipid oxidation, color and visual color acceptability of meat from the Avileña-Negra Ibérica breed fed with corn silage in total mixed ration. The inclusion of corn silage led to lower lipid oxidation and higher visual color acceptability when the samples were packaged in a modified atmosphere. The use of corn silage could serve as a feeding option for this type of animal without affecting the quality of the derived meat.In order to increase the economic profitability of Avileña-Negra Ibérica beef production, the inclusion of corn silage in total mixed rations was proposed during the fattening period. Twenty-four Avileña-Negra Ibérica breed entire young bulls were used to evaluate the effects of two feeding systems—concentrate (CON) and corn silage (SIL)—and two packaging systems—vacuum (VAC) and modified atmosphere (MAP)—on the lipid oxidation, color evolution and visual color acceptability of meat throughout display with either oxygen-permeable film (FILM) or modified atmosphere (MAP). Two muscles were assessed: Longissimus thoracis (LT) and Semitendinosus (ST). Meat from SIL-fed animals had higher TBA values than CON-fed animals after 7 days in MAP packaging. Lipid oxidation was prevented more effectively by VAC packaging than MAP. Display time highly influenced lipid oxidation, since oxidation rates were lower with VAC than MAP packaging. After 14 days of display in MAP, the LT from CON was lighter than the ST. Meat discoloration after 7 days of display was significantly different between packaging systems. Vacuum-packaged meat kept the same color throughout the storage time. Visual color acceptability for the LT was higher throughout display than for the ST. Samples from the MAP were well accepted by consumers, especially the meat from the SIL group. Alternatively, feeding with corn silage could be used for this type of animals without affecting important aspects of meat quality.

Efecto de la suplementación con selenio orgánico sobre la calidad de la canal y la vida útil de la carne de vaquillonas terminadas en feedlot

The objective of this work was to evaluate the effect of organic selenium supplementation (Selplex®) on heifer’s carcass quality and meat shelf life in a feedlot system. Thirty Hereford heifers were used: 14 of 20 months of age, with an initial weight of 323 ± 26.27 kg, and 16 of 36 months and 405 ± 30.52 kg. Animals were housed in individual pens and drawn within each age category to 2 treatments: Control and Supplementation with organic selenium at a rate of 0.9 mg Se/kgDM/day. All animals were fed a fully mixed ration (RTM) including 15% moha bale (Setaria italica) and 85% commercial ration for fattening cattle. Animals were slaughtered after 62 days of feeding. Color evolution, lipid and protein oxidation were measure on sample packed using an oxygen permeable film and stored during 12 days in a refrigerated display case. Selenium supplementation resulted in an increase level of glutathione peroxidase (GSH-Px) (195.9 vs 259.7 U/gr Hg, p<0.0001), a decrease lipid oxidation (0.65 vs. 0.57 mg MDA/kg) (p<0.05) and shear force after 7 days of ageing (3.22 vs. 2.68 kg) (p<0.05). Twenty months heifers supplemented with selenium achieved higher levels of GSH-Px (242 vs. 213 U/gr Hg) (p<0.05) and was detected a lower rancid flavor in relation to those of 36 months (2.9 vs. 3.6) (p<0.05). Organic selenium supplementation may be an alternative to decrease meat lipid oxidation, however it had no effect on color evolution and in reducing protein oxidation (0.31 vs.0.35 nmoles/mg) (p ≥ 0.05).

A Vibration-Assisted Separation Method for Constrained-Surface-Based Stereolithography

Abstract For the bottom-up based stereolithography (SL) process, a separation process is required to detach the newly cured layer from the constrained surface in the fabrication process. Excessive separation force will cause damage to the built layers and the constrained surface. Different surface coatings, platform motions including tilting and sliding, and the utilization of oxygen-permeable films have been developed to address the separation-related problems. Among these approaches, the vibration-assisted (VA) separation method to reduce the separation force has limited study. The underlying mechanism of the VA separation-based method remains unexplored, and the best way to use VA separation in the bottom-up based SL process is still unclear. In this paper, a new VA separation design for the SL process is presented. A prototype system was built to study the VA separation mechanism. Experiments on the separation performance under different parameters, including vibration frequency, pre-stress level, and exposure area, were conducted. Based on the collected separation force data, an analytical model based on the mechanics of fatigue fracture was built. The separation behaviors related to different shape size and topology were also studied and compared. The results showed that the separation force in SL was significantly reduced using the VA separation-based method. Furthermore, the relationship between the separation force and the separation time conforms to the stress-based fatigue model. This study also provides insights on how to choose process parameters by considering the trade-offs between separation force and building efficiency.

Oxygen-Permeable Films for Continuous Additive, Subtractive, and Hybrid Additive/Subtractive Manufacturing.

In the past 5 years, oxygen-permeable films have been widely used for continuous additive manufacturing. These films create a polymerization inhibition zone that facilitates continuous printing in the additive mode of fabrication. Typically, oxygen-permeable films made out of Teflon are currently used. These films are expensive and are not commonly available. Hence, this research work investigates the feasibility of using commonly available low-cost oxygen-permeable films made from polydimethylsiloxane (PDMS) and polyurethane for continuous additive manufacturing. We also characterize the ablation depth range that can be achieved using these films and the potential use for subtractive ablation-based manufacturing as well as hybrid additive/subtractive manufacturing. Results demonstrate that the PDMS films (600 μm thick) can be used for both additive and subtractive modes, whereas spin-coated PDMS thin film (40 μm thick) on glass coverslip and breathe-easy polyurethane film (20 μm thick) laminated on glass coverslip are suitable only for additive mode of fabrication. The latter two films are oxygen impermeable, however, they retain oxygen, which is capable of creating dead zone and thereby facilitates continuous printing. We anticipate that this work will help researchers to choose the appropriate oxygen-permeable film for continuous additive, subtractive, and hybrid additive/subtractive manufacturing of complex three-dimensional structures for a range of applications.

Application of passive modified atmosphere packaging in the preservation of sweet corns at ambient temperature

The purpose of this study was to design a passive modified atmosphere packaging (PMAP) to effectively extend the shelf-life of fresh sweet corn under ambient temperatures. Oxygen permeable film (OPF) and water vapor permeable film (WPF) of different areas were used to prepare the PMAPs. By changing the areas of the OPF and WPF, different headspace atmospheres could be created in the PMAPs, and the effects of different atmospheres on the quality of sweet corn could be evaluated. The experiments were carried out under the temperature conditions of 25 ± 1 °C and relative humidity conditions of 60 ± 5%. The headspace gas, weight loss rate, hardness, total soluble solids content, total acid content, vitamin C content, and sensory quality were measured daily. The results showed that when the proportional area of WPF was 80%–85% and OPF was 15%–20%, the PMAP created a suitable atmosphere for fresh sweet corn, extending the shelf-life to 5 days at ambient temperature.

Effect of packaging design with two functional films on the quality of figs stored at ambient temperature

This work aims to study the effect of a new packaging design with two functional films on the postharvest preservation of figs under ambient temperature (T = 25 ± 1°C, RH = 60 ± 5%). Water vapor permeable film, oxygen-permeable film, and polyethylene terephthalate tray were used to make the packaging. During the experiment, the gas composition in the packaging, water loss rate, hardness, appearance, and nutrient contents of figs were tested and recorded. The atmosphere with low oxygen composition and high carbon dioxide concentration was formed in the packaging. New packaging could reduce the water loss of figs and slow down the decrease of hardness and the loss of nutrients. The shelf life of figs was prolonged to 4 days under ambient temperature by functional films, while the control group was only 2 days. Practical applications Two kinds of functional films (Water vapor permeable film and oxygen-permeable film) were used to make a new packaging design for figs. The packaging could effectively prolong the storage time of fresh figs to 4 days under ambient temperature. It was of great significance to the storage, transportation, and sale of figs after harvest. Two kinds of functional films can also be used to preserve other fresh fruits and vegetables that are difficult to store.

Impact of myoglobin oxygenation state prior to frozen storage on color stability of thawed beef steaks through retail display

Consumers consider beef color to be an indicator of freshness and therefore it is a major factor when purchasing beef. The ideal conditions for maintaining color throughout retail display following frozen storage have yet to be well established. Therefore, the objective of this study was to determine the effects of myoglobin oxygenation levels (especially high oxygenation) during freezing on color stability of thawed steaks during retail display (RD) and to determine the impact that frozen storage duration, aging, and packaging films have on meat color after thawing under RD conditions. USDA Choice strip loins (n = 36) were aged for 4 or 20 d. Steaks were randomly assigned to a myoglobin oxygenation level [deoxymyoglobin (DeOxy; packaged within 3 min), oxygenation (Oxy; oxygenated in air for 30 min), or high oxygenation (HiOxy; packaged for 24 h in 80% O2)]. Steaks were then vacuum packaged in oxygen permeable or impermeable film and immediately frozen (−10 °C). Following either 0, 2, 4, or 6 months of frozen storage at -5 °C, steaks were removed from the packaging and immediately placed under simulated RD conditions for 7 d. During RD, instrumental color and subjective color were measured every day after the initial 24 h thaw period. Steaks were analyzed for instrumental color (L*, a*, b*), a*:b* ratio, percentage oxymyoglobin, metmyoglobin, and deoxymyoglobin, delta E, redness ratio, subjective discoloration, and lipid oxidation. For all days of RD, steaks that were frozen for 0 months had higher a* values (greater redness) than steaks frozen for 6 months which typically had the lowest a* values (P < .0001). HiOxy steaks frozen for 6 months had the lowest amounts of percentage oxymyoglobin than all other frozen storage periods and myoglobin oxygenation levels on days 4–7 of RD (P < .05). The HiOxy steaks frozen for 4 and 6 months had higher percentage metmyoglobin than DeOxy and Oxy, regardless of packaging (P < .05). Delta E, discoloration, and lipid oxidation were greatest for HiOxy steaks compared to Oxy and DeOxy (P < .05). Extended storage brought about detrimental color effects for all differing levels of myoglobin oxygenation. The HiOxy steaks through the first few days of RD and frozen for under 6 months provided had bright cherry red color, similar to that of DeOxy and Oxy. However, with extended frozen storage and RD, HiOxy steaks had worse color characteristics (more discoloration) than the other myoglobin oxygenation levels.

Impact of myoglobin oxygenation level on color stability of frozen beef steaks.

The emerging market of frozen meat emphasizes the need to better understand beef surface discoloration and the ideal parameters of freezing beef to retain an acceptable color. The objectives of this study were to determine the impacts of myoglobin oxygenation level prior to freezing and frozen storage duration on frozen beef color. USDA Choice strip loins (n = 36) were aged for 4 d or 20 d. Steaks were randomly assigned to a myoglobin oxygenation level [deoxygenated (DeOxy; immediately packaged after cutting), oxygenated (Oxy; oxygenated in air for 30 min), or highly oxygenated (HiOxy; packaged for 24 h in 80% O2)]. Steaks were then vacuum packaged in oxygen permeable or impermeable film and immediately frozen (-5 °C). Following either 0, 2, 4, or 6 mo of frozen storage, steaks were removed from the packaging and immediately analyzed for instrumental color (L*, a*, and b*), percent oxymyoglobin, metmyoglobin, and deoxymyoglobin, delta E, redness ratio, a*:b* ratio, hue angle, subjective discoloration, and lipid oxidation. The HiOxy steaks had greater oxygen penetration and the greatest a* values compared with DeOxy and Oxy steaks, regardless of packaging (P < 0.0005). With 4 d of aging, HiOxy steaks had greater a* values than DeOxy and Oxy at all storage times (P = 0.0118). The HiOxy steaks aged for 20 d and frozen for 6 mo had significantly higher delta E values than all other myoglobin oxygenation levels and postmortem aging periods (P < 0.0001). Redness and percent oxymyoglobin were highest for HiOxy steaks within each storage period (P < 0.0002). The HiOxy steaks had the highest percent oxymyoglobin and DeOxy had the lowest percent oxymyoglobin within each aging and storage period (P < 0.01). Conversely, DeOxy steaks had the highest percent metmyoglobin and HiOxy had the lowest percent metmyoglobin when packaged in impermeable film (P < 0.0001). The HiOxy steaks from 20 d of aging had the highest discoloration compared with 4 d aging and more discoloration than all other myoglobin treatments at 6 mo of storage (P < 0.0001). The HiOxy 20 d aged steaks exhibited the highest lipid oxidation values at 2, 4, and 6 mo (P = 0.0224) and HiOxy steaks exhibited a brighter and deeper cherry red color compared with the DeOxy steaks. The HiOxy steaks were greater in redness or similar when compared with Oxy steaks, but experienced more detrimental effects when frozen storage was extended.

Plasma spray–physical vapor deposition toward advanced thermal barrier coatings: a review

Plasma spray–physical vapor deposition (PS–PVD) is a unique technology that enables highly tailorable functional films and coatings with various rare metal elements to be processed. This technology bridges the gap between conventional thermal spray and vapor deposition and provides a variety of coating microstructures composed of vapor, liquid, and solid deposition units. The PS–PVD technique serves a broad range of applications in the fields of thermal barrier coatings (TBCs), environmental barrier coatings (EBCs), oxygen permeable films, and electrode films. It also represents the development direction of high-performance TBC/EBC preparation technologies. With the PS–PVD technique, the composition of the deposition unit determines the microstructure of the coating and its performance. When coating materials are injected into a nozzle and transported into the plasma jet, the deposition unit generated by a coating material is affected by the plasma jet characteristics. However, there is no direct in situ measurement method of material transfer and deposition processes in the PS–PVD plasma jet, because of the extreme conditions of PS–PVD such as a low operating pressure of ~ 100 Pa, temperatures of thousands of degrees, and a thin and high-velocity jet. Despite the difficulties, the transport and transformation behaviors of the deposition units were also researched by optical emission spectroscopy, observation of the coating microstructure and other methods. This paper reviews the progress of PS–PVD technologies considering the preparation of advanced thermal barrier coatings from the perspective of the transport and transformation behaviors of the deposition units. The development prospects of new high-performance TBCs using the PS–PVD technique are also discussed.

Color and Lipid Stability of Dry Aged Beef During Retail Display

ObjectivesThere has been an increased interest in merchandising dry-aged steaks at the retail level. Further understanding of the influence of the dry aging process on meat color and lipid stability is needed to ensure dry-aged beef products can be merchandised without adverse impacts on retail display life. Therefore, this study aimed to determine color and lipid stability of steaks from dry-aged beef loins over 7 d (d) of retail display.Materials and MethodsSixteen USDA low Choice boneless strip loins were assigned to one of four aging treatments: vacuum (Wet), dry-aging at 50% relative humidity (RH) (RH50), dry-aging at 70% RH (RH70), or dry-aging at 85% RH (RH85). Dry-aged loins were placed in each assigned dry aging chamber, while wet aged counterparts were aged in vacuum bags in the same cooler. Loins were aged for 42 d at 1°C. After aging, loins were trimmed of dehydrated lean/fat and fabricated into steaks. Steaks were trimmed of subcutaneous fat, and placed on foam trays, overwrapped with oxygen permeable film and placed under retail display (RD) conditions for 7 d at 2°C. Objective color measurements were taken once daily from d 0 to 7 of RD. Trained visual color panelists (n = 6) evaluated surface discoloration from d 0 to 7 of RD once daily. Lipid oxidation was measured via thiobarbituric acid reactive substance assay (TBARS) at 0, 4, and 7 d of RD. Color data were analyzed as a split-plot repeated measures design with treatment as the whole-plot and RD time as the repeated measures. TBARS data were analyzed as a split-plot design with aging treatment as the whole-plot, and RD time as the split-plot. In this study, chamber (loin) was considered the experimental unit. Data were analyzed using the PROC GLIMMIX procedure of SAS with α = 0.05.ResultsFor all three-color scales, a RD effect was found (P &lt; 0.001). In general, L*, a* and b* values decreased as RD time increased, regardless of the aging treatment. Wet-aged steaks had higher L* (P &lt; 0.05), a* (P &lt; 0.05), and b* values (P &lt; 0.001) than any other dry-aged treatment. No differences in L*, a*, and b* values among dry aging treatments were found (P &lt; 0.05). A 2-way interaction between treatment and RD for discoloration was observed (P &lt; 0.05). No differences were found among treatments over the first 2 d of RD (P &gt; 0.05). Samples began to diverge on Day 3 of RD. Dry-aged steaks had greater discoloration scores (P &lt; 0.05) than wet-aged steaks at 4, 5, 6, and 7 d of RD. However, no differences in discoloration scores among RH treatments were found. There was a RD effect on TBARS values (P &lt; 0.001). Greater TBARS values were found as RD progressed from d 0 to d 4 and d 7, regardless of the aging treatment. A treatment effect was observed for lipid oxidation (P &lt; 0.05). Dry-aged steaks had higher TBARS values than wet-aged steaks. No differences in TBARS values among dry aging treatments were found.ConclusionDry aging of beef resulted in decreased lightness and redness values and increased lipid oxidation compared to wet aging. Results suggest that with prolonged RD dry aging of beef has the potential to reduce color and lipid stability compared to wet-aging and thus reduce display life. Dry-aged steaks met the 20% discoloration threshold and overcame the acceptability threshold of 2.28 mg of malonaldehyde/kg at d 4 of RD, indicating that dry-aged steaks can be merchandised in the retail level for 3 d without detrimental effects on color and lipid oxidation.

The Optimization of the Concentrations of Sodium Lactate (Nal), Sodium Erythorbate (Nae), and Sodium Bicarbonate (Nab) Applied to Beef Trimmings for Ground Beef Production

ObjectivesThe objective of the study was to identify optimal concentrations of NaL, NaE and NaB applied to beef trimmings to assess their impact on quality of ground beef patties.Materials and MethodsBeef trimmings (∼50kg) were fabricated from beef forequarters (N = 5) 14 d postmortem, combined and aerobically stored (5°C) for an additional 6 d to simulate the collection, storage, transportation and receipt of a combo of beef trimmings. A 23 central composite response surface design (RSM) was used to generate 15 treatment combinations containing NaL (0.1–1.5 M), NaE (0.1–0.6 M), and NaB (0.1–1.5 M) with water used as a control. After aerobic storage, the beef trimmings (∼20% fat) were coarse ground (12 mm) and the treatment/control solution applied to the coarse ground trimmings (∼454 g) at 2% (w/w). The trimmings were reground (3 mm) and 120 g of treated sample was placed into a Petri dish and overwrapped with oxygen permeable film (OTR: 21,700 cc/m2/24h at 25°C) to form patties. The patties (2 per treatment/control) were stored under simulated retail conditions: 5°C, cool white fluorescent light (200–300 lux) and analyzed at Day 0, 3, 6, and 9 of storage to assess the effectiveness of each treatment in preventing further quality deterioration. Objective color (L*, a*, b*), 2-thiobarbituric acid (TBA) determinations, GC–MS for off-odor assessment and aerobic plate counts (APC) were conducted. The least squares means of results were generated by one-way ANOVA and Tukey HSD to identify significant differences (P &lt; 0.05) between treatment and control patties. For RSM and multivariate RSM analyses, the data was used to generate total quadratic polynomial linear regression models and contour plots to determine the optimum ingredient concentrations for the solution.ResultsThe a* values of treated indicated a redder surface color from Day 0 to Day 9 (P &lt; 0.05). No difference was observed for treated and control patties for TBA and hexanal counts on Day 0. The TBA values for all treatments reduced lipid oxidation compared to the control on Day 3, 6, and 9 (0.47– 0.58 vs. 0.71, 0.51– 0.58 vs. 0.74 and 0.45– 0.62 vs. 0.74, respectively; P &lt; 0.05). No differences were observed for treated and control patties for APC from Day 0 to Day 6, except on Day 9 (8.10 vs. 8.21 Log10 CFU/g; P &lt; 0.05). Based on these results, a* and TBA values were used to conduct RSM analyses for Day 3 and 6. Day 9 was excluded due to a significant lack of fit. The predicted value of hexanal was 0 for all treatments. The prediction of TBA values found optimum ingredient concentrations on Day 6: NaL (0.74 M), NaE (0.35 M) and NaB (1.00 M) (R2 = 0.77, respectively; P &lt; 0.05). The prediction of a* values on Day 3 and 6 did not identify optimum ingredient concentrations for any treatment solution (R = 0.94 and 0.78, respectively; P &lt; 0.05). Multivariate RSM was conducted to overlap the contour plots of a* and TBA values at Day 3 and 6 to better approximate the optimal ingredient concentrations for a* values. The proximal optimum concentration ranges of solutions based on the analysis were 0.3- 0.5 M NaL, 0.35 M NaE and 1M NaB with predicted a* values &gt; 11 and TBA values &lt; 0.52.ConclusionResults of this study suggest that a combination of NaB, NaE, and NaL can be applied to improve color stability, reduce lipid oxidation, and control off-odor of ground beef patties.

Effects of Bacteriophage, Ultraviolet Light, and Organic Acid Applications on STEC O157:H7 and the “Big Six” in Beef Packaged Under Vacuum and Aerobic Conditions

ObjectivesBeef primals produced during high event periods (HEP) can also be affected by STEC contamination requiring microbial assessment. Commonly, primals are retreated with antimicrobials after removal from vacuum bags, then repackaged and tested for STEC. In this study, we evaluated the efficiency of bacteriophage, ultraviolet light, and organic acids on contaminated beef kept under vacuum and aerobic conditions.Materials and MethodsThe effects of antimicrobial interventions Peroxyacetic acid (PAA, 400 PPM), Ultraviolet light (UV, 30 s at 2.5 ± 0.3 cm height), Acidified Sodium Chlorite (ASC, 1200 ppm), and bacteriophage (P, 7 MS phages at 108 PFU/ml) against STEC (O157:H7 and O145, O121, O111, O103, O45, O26) were evaluated on beef. Fresh m. cutaneous trunci was fabricated into 100 cm2 samples (n = 154), which were randomly assigned to 11 treatments including Control, P, UV, ASC, PAA, and combinations P+UV, P+PAA, P+ASC, UV+PAA, UV+ASC, PAA+ASC. Treatments were tested under vacuum and aerobic conditions. Samples were inoculated with a STEC cocktail comprised of 7 strains to yield 3 log CFU/cm2. Samples were vacuumed or overwrapped with oxygen permeable film. Samples were unpackaged and treated with buffered peptone water (BPW, Control) or individual or combined antimicrobial treatments prior to re-packaging. After 1 h at 7°C, samples were swabbed, homogenized in 1 mL of BPW, serially diluted and spread-plated for bacterial enumeration. Data was analyzed using SAS as a completely randomized design.ResultsOverall, treatments including MS phages significantly decreased STEC populations in beef under vacuum and aerobic conditions (P &lt; 0.0001). Under vacuum, individual phage application, combinations between phage and UV, ASC, and PAA plus UV+ASC provided optimal STEC reduction on beef surface. Phage and PAA combination led to the lowest STEC load (1.49 log reduction). When analyzing contrasts, treatments with phage significantly decreased STEC loads when compared to other treatments (P &lt; 0.0001) and control (P &lt; 0.0001). STEC loads recovered from treatments without phage and control were statistically similar at P = 0.32. Under aerobic conditions, individual treatments UV and ASC and combinations including UV+PAA, and PAA+ASC were statistically similar to the control. Inclusion of phage in treatments gradually decreased STEC loads when combined with ASC, PAA, and UV. Phage and UV combination led to the lowest STEC load (1.46 log reduction). Contrast analysis showed that treatments with phage significantly decreased STEC loads when compared to other treatments (P &lt; 0.0001) and control (P &lt; 0.0001). STEC loads recovered from treatments without phage and control were statistically similar at P = 0.07.ConclusionIndividual or combined applications of MS phages on beef surface contaminated with STEC provided optimal antimicrobial effect under vacuum or aerobic conditions. Although organic acids and UV combinations did reduce STEC populations, treatments that included phage yielded the lowest STEC loads. Only phage interventions gave optimal reduction effects under vacuum conditions. Antimicrobial treatments based on individual phage cocktails and their combinations with ASC, UV, and PAA significantly reduce STEC when treating primals produced during HEP.

Efficiency of Commercial Bacteriophages on Stec O157:H7 Populations in Beef Kept Under Vacuum and Aerobic Conditions

ObjectivesHigh event period (HEP) is a specific time length when processing facilities experience an elevated rate of STEC contamination. STEC contamination during beef fabrication is assessed by sampling trim combos usually using N60, N60 plus, or CSD cloth methods. However, beef primals produced during high event periods can also be affected and must be assessed. A common industry practice consists in reworking primals by removing them from vacuum sealed bags, treating with antimicrobials, repackaging, and then test for STEC. In this study, we evaluated the efficiency of bacteriophage and organic acid applications on contaminated beef kept under vacuum and aerobic conditions.Materials and MethodsAntimicrobials used in this study included: PhageGuard E (PGE, 108 PFU/ml, Bacteriophage solution from Micreos Food Safety BV), peroxyacetic acid (PAA, 400 PPM), and lactic acid (LA, 4.5% at 50°C). STEC O157:H7 strains included: ATCC® 35150 (stx1 and stx2 positive), ATCC® 43895 (stx1 and stx2 positive), ATCC® 43894 (stx1 and stx2 positive), and Micreos 128. Bacteriophage killing efficiency was determined for individual strains in vitro. Fresh rose meat (Cutaneous trunci) was cut into 100 cm2 and stored at 7°C. Meat samples (n = 160, 5 reps, 2 experimental units per rep) were randomly assigned to a 4×2×2 factorial whereas fixed effects were antimicrobial treatment (Control, PGE, PAA, and LA), packaging (V- vacuum and NV– aerobic), and lysing time (30 min and 6 h). Samples were inoculated with 500 ML of a STEC cocktail containing all 4 strains and after 30 min at 7°C under vacuum or wrapped in permeable film, samples were treated with 500 μL PGE, sterile buffered peptone water (BPW, Control), LA, or PAA. Samples were then re-vacuumed or re-wrapped with oxygen permeable film and kept either for 30 min or 6h at 7°C. After refrigeration, samples were swabbed and homogenized in 1mL of BPW. The swab content was serially diluted and spread-plated onto LB agar plates for bacterial enumeration. Data were analyzed using SAS as a completely randomized design.ResultsIn vitro killing efficiency was 98.3%, 96.7%, 97.2%, and 98.2% for Micreos 128, ATCC® 43894, ATCC® 43895, and ATCC® 35150 strains, respectively. When analyzing the effects of antimicrobials, packaging, and lysing time, a three-way interaction was observed (P = 0.035). Under aerobic conditions for 30 min, PGE reduced STEC in beef by approximately 1.4 log CFU/cm2 whereas organic acids reduced by 0.5 log. Similar results were observed when samples were kept for 6 h. Under vacuum conditions for 30 min, PGE significantly reduced STEC by 1 log, whereas no significant effects were observed when treating beef with PAA and LA. Under vacuum conditions for 6h, PGE significantly reduced STEC loads by 1.4 log, whereas LA reduced by 0.6 log and no differences were observed between control and PAA treatments.ConclusionBacteriophage applications on beef contaminated with STEC yielded the lowest counts when compared to PAA and LA. Although organic acids led to a significant decrease of STEC loads in beef kept under aerobic conditions, bacteriophage application led to the lowest counts. Similar to reworking and testing primals produced during a HEP, while under vacuum conditions, bacteriophage significantly reduced STEC loads whereas no or minimal effects of organic acids were observed.

Impact of Myoglobin Oxygenation State at Freezing on Color Stability of Frozen Beef

ObjectivesMeat color is the number one factor influencing consumer purchase decisions. The emerging market of frozen meat emphasizes the need to understand beef surface discoloration and the ideal parameters of freezing beef to retain a superior color. Therefore, the objectives of this study were to determine the impacts of oxygenation level and frozen storage duration on frozen beef color.Materials and MethodsUSDA Choice strip loins (n = 36) were aged for 4 d or 20 d. Steaks were randomly assigned to a myoglobin state [deoxymyoglobin (DeOxy; immediately packaged), low oxygenation (LoOxy; oxygenated in air for 30 min), and high oxygenation (HiOxy; packaged for 24 h in 80% O2)]. Steaks were then vacuum packaged in oxygen permeable or impermeable film and immediately frozen (–20°C). Following either 0, 2, 4, or 6 mo of frozen storage, steaks were removed from the packaging and immediately analyzed for instrumental color (L*, a*, b*), delta E (magnitude of difference in the L*, a*, b* color space), subjective discoloration, lipid oxidation (via thiobarbituric acid reactive substances- TBARS), oxygen penetration, percent oxymyoglobin, metmyoglobin, and deoxymyoglobin (via spectrometer), and redness (calculated as 630nm/530nm). Data were analyzed using PROC Glimmix procedure in SAS as a split-split-plot with an incomplete block and a 2 × 3 factorial.ResultsHiOxy steaks had greater oxygen penetration and the highest a* values compared to DeOxy and LoOxy steaks regardless of packaging (P &lt; 0.0005). Conversely, DeOxy steaks exhibited the lowest oxygen penetration and a* values regardless of film (P &lt; 0.0005). HiOxy steaks at 4 d had higher a* values than DeOxy and LoOxy at all storage times (P = 0.0118). HiOxy steaks had the highest delta E values compared to DeOxy and LoOxy in permeable packaging and with increasing storage time an increase in delta E for the HiOxy steaks was observed (P = 0.0010).Redness and percent oxymyoglobin were highest for HiOxy steaks within each storage period (P &lt; 0.0002). HiOxy and LoOxy steaks were similar in percent oxymyoglobin when in permeable packaging film. HiOxy steaks had the highest percent oxymyoglobin and DeOxy had the lowest percent oxymyoglobin within each aging and storage period (P &lt; 0.01). Conversely, DeOxy steaks had the highest percent metmyoglobin and HiOxy had the lowest percent metmyoglobin when packaged in impermeable film (P &lt; 0.0001). Lowest percent metmyoglobin values were from the 4 d HiOxy steaks at 2, 4, and 6 mo of storage (P = 0.0188).The HiOxy 20 d steaks had the highest discoloration compared to 4 d aging and more discoloration than all other myoglobin treatments at 6 mo of storage (P &lt; 0.0001). Lipid oxidation increased with storage time (P = 0.0169). HiOxy 20 d aged steaks exhibited the highest TBARS values at 2, 4, and 6 mo (P = 0.0224). HiOxy and LoOxy were similar in discoloration and lipid oxidation except with the HiOxy 20 d (which were less desirable).ConclusionHiOxy steaks exhibit a brighter and deeper cherry red color compared to the DeOxy steaks. HiOxy steaks were superior or similar when compared to LoOxy steaks but displayed more detrimental effects when frozen storage was extended. Based on the results, HiOxy steaks aged for 4 d give a superior red color for extended storage with few unfavorable effects. However, it is not advised to freeze deoxygenated steaks and expect a cherry red color through frozen storage.

Alternative Merchandising Strategy of the Beef Top Round

ObjectivesThe study objectives were to compare the deep (D) vs. superficial (S) portions of the beef top round (NAMI #169A PSO1), semimembranosus (SM) muscle, for tenderness, lipid oxidation, and color.Materials and MethodsTo simulate the retail setting, USDA Choice top rounds (n = 12) were purchased from a commercial food distributer and delivered to the University of Idaho Meat Science Laboratory under refrigeration. Top rounds were aged for 21 to 24 d from their pack date prior to removing the SM for subsequent analysis. Four steaks were cut from each SM proximally to distally. To account for steak location, steaks were systematically assigned to one of the following analyses; Warner-Bratzler Shear Force (WBSF) measurement, lipid oxidation using the Thiobarbituric Acid Reactive Substances (TBARS) method, subjective and objective color analysis on the whole steak to calculate color uniformity (two-toning), and subjective and objective color of a steak separated into D and S portions. The separating cut was made approximately two inches from the superficial edge of the steak. After cutting, WBSF steaks were cooked on clamshell grills to an internal temperature of 71°C. Steaks were then chilled overnight before 6 cores were sheared perpendicular to the muscle fiber direction on a WBSF machine. Steaks were sampled and evaluated for TBARS on Days 0 and 4 of retail display, while color was evaluated subjectively and objectively on Days 0, 1, 2, 3, and 4 of retail display. Steaks used for TBARS and color analysis were placed on white Styrofoam trays, overwrapped with an oxygen permeable PVC film, and displayed in a glass-fronted retail display case at 3°C for 4 d to simulate retail display. Data were analyzed using the mixed models procedure of the Statistical Analysis System (SAS Institute, Inc., Cary, NC) and significance was determined at P &lt; 0.05.ResultsMean Warner-Bratzler shear force values were lower (P = 0.0012) in the S (4.2 kg) than the D (5.2 kg) portion of the SM. On Day 0, D and S portions had similar TBARS values (0.172 vs. 0.118 mg MDA/kg Meat); yet, by Day 4, the D portion had substantially greater TBARS values than the S portion (0.497 vs. 0.194 mg MDA/kg Meat; treatment × day of retail display interaction, P &lt; 0.0001). The D portion was lighter (higher L*; P &lt; 0.0001) colored than the S portion. Furthermore, the D portion became less red compared to the S portion during simulated retail display (treatment × day of retail display interaction; P &lt; 0.0001). The whole steak had greater levels of two-toning initially, as well as throughout the 4 d of retail display, compared to the D and S portions (treatment × day of retail display interaction; P &lt; 0.0001). Therefore, cutting top round steaks into a D and S portion would result in the steaks being more uniform in color. Additionally, the S portion has longer shelf-life as well as improved tenderness compared to the D portion.ConclusionIn conclusion, the S portion may be able to generate a premium compared to the whole steak at the retail level because of its superiority in color to the D portion and more uniform color compared to the whole steak.

Independency of regulating RH and O2/CO2 concentration and its effect on the quality of strawberry at 25°C

AbstractStrawberries have a short postharvest life due to their relatively high water content, high metabolic activity, and susceptibility to microbial rot. Traditional MAP, even antimicrobial film could not avoid strawberry decay at room temperature. To solve this problem, a new passive MAP (PMAP) is proposed in this article. The innovation of the PMAP lies in the special structure of the lid film. The lid film of PMAP consists of two function films, which is paratactic border‐connected. The one film (oxygen permeable film) only allows O2 (or CO2) to pass through, and the other film (water vapor permeable film) only allows water vapor to pass through. Thus, the O2 concentration and relative humidity in the PMAP could be controlled by the area and gas permeability of the dual pieces function films, respectively and independently. In this way, the PMAP could establish a modified atmosphere with any relative humidity without any change in O2 concentration. Results show that the O2 concentration and relative humidity in headspace can be accurately controlled by the designed PMAP. The PMAP could prolong the shelf life of strawberry to 5–6 days at 25°C and maintain the excellent taste, special flavor, good appearance, and nutrition.Practical applicationsIn the packaging system, the area of the different functional films required can be calculated from the physiological effects of the strawberry, which in turn can independently control the physiological strength of the strawberry and RH in the headspace by controlling the area of different functional films. This will extend the shelf life of the retail strawberry. Not only that, but our design can be applied to another fruit packaging by simply selecting the right functional film. In addition, if we want to achieve other functions, such as antibacterial effects, simply add an antibacterial film to our packaging system. And this does not affect the headspace and humidity because they work completely independently. Therefore, our design has important practical significance for the preservation of fruits and vegetables.

Effect of fat tail docking on meat quality of Awassi sheep in comparison with Lacaune sheep

1 ABSTRACT This experiment was conducted to study the effect of fat tail docking on Awassi lamb sheep’s meat in comparison with thin-tail Lacaune sheep’s meat (imported breed in Lebanon). Twenty seven ram lambs were divided into three groups, intact fat-tail Awassi (IA), docked fat-tail Awassi (DA), and imported thin-tail Lacaune (IL). Docking was performed at one week of age, by applying tight rubber rings on the tail. Animals having the same body weight were slaughtered at one year of age. Three samples of muscles were excised from each carcass; Biceps Femoris (Bf), Longissimus Dorsii (Ld) and Gluteus Medius (Gm). Samples were wrapped in an oxygen permeable film and stored at 4°C and - 30°C for the assessment of pH, and meat quality traits. The ultimate pH was significantly higher (P&lt;0.01) in Lacaune breed as compared to both docked and intact Awassi breed. DA animals had significantly higher (P&lt;0.01) fat content in Ld muscle than IA and IL lambs. Both Awassi groups presented higher L* values than Lacaune animals (P&lt; 0.05). In addition for Awassi breed, L* values of Bf and Gm muscles were significantly greater (P&lt; 0.05) than that of Ld muscle. b* values were significantly greater (P&lt; 0.05) in Gm of all animals under study. Lacaune group had lower drip loss values than Awassi groups (P&lt; 0.05 in Bf and Gm muscles and P&lt; 0.01 in Ld muscle). However for Awassi breed, the drip loss in Ld muscle of DA animals was significantly lower (P&lt;0.01) than IA ones. Furthermore, thawing and cooking losses were neither affected by breed nor by docking. Regarding the PND values, the Ld muscle of DA group presented higher values (P&lt; 0.05) than Bf and Gm muscles of both intact groups. In addition, cooked meat PND values were significantly higher (P&lt; 0.05) in Ld muscle of DA when compared to intact groups. Due to the scarcity of information in this area of research, further investigations are needed.

71 Impact of myoglobin oxygenation state at freezing on color stability of frozen and thawed beef

Abstract Myoglobin, when oxygenated, is bright red. The deoxygenated form (purple color) is unstable and can be oxidized to metmyoglobin (brown color). This research was conducted to determine if meat frozen in the oxygenated state could retain bright red color during frozen storage, and after thawing, during retail display. Steaks from 18 USDA Choice strip loins were randomly assigned to a myoglobin state [deoxymyoglobin (DeOxy; immediately packaged), low oxygenation (LoOxy; oxygenated for 30 minutes), and high oxygenation (HiOxy; packaged for 24 h in 80% O2)], frozen storage packaging method (vacuum packaged in oxygen permeable or impermeable film), and retail display after two months of frozen storage [0 d (frozen) and 1–7 d (thawed)]. Following storage, frozen steaks were analyzed for objective color (L*, a*, b*), subjective discoloration, and percent oxymyoglobin (via spectrometer). After thawing, steaks were evaluated throughout 7 d of retail display in oxygen-permeable film. For frozen steaks, there were no differences in discoloration (P&gt;.05). The HiOxy steaks retained the highest percentage oxymyoglobin and highest (reddest) a* values after storage, regardless of packaging film. The lowest percent oxymyoglobin (PPPPP &lt; .05). These data suggest that steaks frozen for two months in the high oxygenation state retain superior color appearance while frozen and during the first part of retail display. It is unknown if this advantage would be retained during longer frozen storage.