Surface Discoloration Research Articles

Theoretical and experimental studies of the influence of microstructure on anti-tarnish ability of cyanide-free silver deposit

The influence of microstructure on anti-tarnish ability of silver deposit was studied by computational chemistry and experiments. The influence of microstructure on the anti-tarnish ability of silver deposit was firstly predicted by quantum chemical calculations. Theoretical studies revealed that high-index crystal surfaces of silver deposits were more sensitive to corrosive mediums and were seriously damaged when they were discolored. Based on the prediction of quantum chemical calculations, silver electrodeposition process with crystal surfaces controlled by additives was possible approach to improve the anti-tarnish ability of silver deposit in this work. The anti-tarnish ability of silver deposit influenced by crystal surfaces control was studied by surface discoloration investigation and Tafel plots measurements, as well as X-ray photoelectron spectroscopy (XPS) measurements. The results of these measurements confirmed the conclusions of theoretical studies; silver electrodeposition process with microstructure control can be used to improve the anti-tarnish ability of silver deposit.

Thermal oxidation of PEPA-terminated polyimide

The thermal oxidative stability of a 4-phenylethynyl phthalic anhydride (PEPA) endcapped polyimide (PI) was investigated. A surface reaction layer formed due to oxidization during thermal aging and grew in thickness with increasing aging time. Analysis of the surface layer revealed a partial loss of aromatic ring, ether linkage, and imide linkage in the aged polymer. The partial loss of the imide linkage and ether linkage in the surface layer was corroborated by the observed release of carbon monoxide and carbon dioxide reaction products. The oxidized layer exhibited discoloration and an increase in glass transition temperature. The surface discoloration was attributed to the formation of the conjugated unsaturated or aromatic carbonyl groups and/or the charge transfer complex. Interior regions of the oxidized samples were largely unaffected, except for a more compact molecular configuration. Compared with aging at high temperatures (288°C, 316°C), aging at 204°C produced similar chemical changes in the cured polymer, albeit with a low degradation rate. The oxidative stability of the imide polymer surpassed that of conventional nadic-endcapped PIs due to the greater intrinsic thermal stability of the PEPA endcap. The unusual oxidative stability of the PI, combined with superior mechanical properties, warrant consideration as a composite matrix for future applications in high-temperature service conditions.

PD085: The efficacy of chlorhexidine mouthwash, with and without an anti‐discoloration‐system (ADS), on the parameters plaque, gingivitis and tooth surface discoloration: a systematic review

PD085: The efficacy of chlorhexidine mouthwash, with and without an anti‐discoloration‐system (ADS), on the parameters plaque, gingivitis and tooth surface discoloration: a systematic review

Prediction of wood surface discoloration for applications in the field of architecture

Semitransparently coated wooden building elements such as facades and windows undergo discolouration during exposure to sunlight, depending on the environmental conditions and protective properties of the coatings. The present paper aims at the development of numerical prediction models of photo-induced discolouration as a basis for texture synthesis for CAD applications. Wood samples of European larch and Norway spruce were coated with several (semi-) transparent coatings with varying colours and dry film thicknesses and exposed to Xenon arc light with outdoor cut-off filter to simulate outdoor irradiation conditions. Colour prediction models were developed from the obtained colour measurement data in the CIE XYZ colour space, since the progression of corresponding values showed a monotonous curve characteristic of each coating system. A novel colour measurement procedure was developed to estimate the colour of early- and latewood in the annual rings of wood. This method made it possible to generate colour-consistent textures for use in rendering software, as demonstrated on two examples.

Modified Atmosphere Packaging Improves Surface Color of Dark-Cutting Beef

The objective was to determine the effects of modified atmosphere packaging (MAP) on the surface color of dark-cutting beef that had been aged for 21 d. The USDA Choice (normal-pH; IMPS #180) strip loins (n = 10) and no-roll dark-cutter strip loins (n = 10) were obtained from a commercial packing plant within 72 h of harvest. Both normal-pH and dark-cutting beef were vacuum packaged and aged for 21 d. Steaks were cut from both normal and dark-cutting loins, assigned to 1 of 3 packaging treatments; PVC, HiOx-MAP, and CO-MAP, and stored in a simulated retail display under continuous fluorescent lighting at 2°C for 6 d. Instrumental and visual color were measured every 24 h. Thiobarbituric acid assay was used as an indicator for lipid oxidation. There was a packaging × muscle type × display time interaction (P < 0.0001) for instrumental and visual color. On d 1 of display, dark-cutting steaks packaged in HiOx-MAP had greater (P < 0.001) a* values and chroma than dark-cutting PVC steaks. On d 6 of the display, dark-cutting steaks packaged in CO-MAP had 10 units greater a* values than dark-cutting steaks packaged in PVC. The visual panel also noted less muscle darkening (P < 0.002) in HiOx-MAP and CO-MAP compared with steaks packaged in PVC on d 6 of the display. There was less surface discoloration (P < 0.001) in HiOx-MAP and CO-MAP dark-cutting steaks compared with PVC dark-cutting steaks by the end of the display. There was a packaging × muscle type interaction for instrumental L* values and lipid oxidation. Dark-cutting steaks packaged in HiOx-MAP and CO-MAP had greater (P < 0.05) L* values compared with dark-cutting steaks in PVC packaging. In conclusion, HiOx-MAP improved redness of dark-cutting beef during the initial phase of display, while CO-MAP resulted in a stable red color.

Impact of Light Source on Color and Lipid Oxidative Stabilities from a Moderately Color-Stable Beef Muscle during Retail Display

Consumers’ purchasing decisions are heavily impacted by fresh meat color, which they consider an indicator of quality in a retail setting. The objectives of this study were to evaluate the impact of light source on surface color and lipid oxidation during retail display of fresh steaks from semimembranosus (SM), a beef muscle with moderate oxidative and color stabilities. Steaks (n = 240) from the SM (n = 20) were packaged on Styrofoam trays and overwrapped with oxygen-permeable polyvinyl chloride. Steaks were then assigned to 1 of 3 lighting treatments, high UV fluorescent (HFLO), low UV fluorescent (FLO), and light emitting diode (LED) to mimic current storage conditions with a variety of industry available fluorescent bulbs, and evaluate emerging lighting conditions with LED. Steaks were removed on retail display d 1, 3, 5, and 7 for evaluation of instrumental color (L*, a*, and b* values), surface myoglobin redox forms, metmyoglobin reducing activity, and lipid oxidation. Light source influenced (P < 0.05) redness (a* values), with HFLO-displayed steaks having greatest (P < 0.05) a* values and LED-displayed steaks exhibiting lowest (P < 0.05) a* values. Surface redness decreased (P < 0.05) over retail display day. Steaks displayed in HFLO and FLO had greater (P < 0.05) oxymyoglobin percentages than those displayed under LED, indicating that LED accelerated surface discoloration compared to HFLO and FLO lights. Metmyoglobin (MMb) percentages increased over retail display, with LED-exposed steaks having greater (P < 0.05) percentages of MMb than those displayed in HFLO and FLO. By d 7 of retail display, HFLO-exposed steaks had lower (P < 0.05) MMb percentages than the steaks displayed in both FLO and LED. Lighting type did not influence (P > 0.05) lipid oxidation in SM steaks, however, lipid oxidation increased (P < 0.05) over retail display. The findings indicated that light source influenced the color stability in SM steaks during retail display and that HFLO light can minimize surface discoloration in moderate color stability beef muscles.

Pomegranate Rind Extract Limits Ground Beef Color Discoloration and Lipid Oxidation

ObjectivesMeat color has a substantial influential in purchasing decisions as consumers associate color with freshness. Discoloration of beef at retail has resulted in a loss of about $1 billion annually. Many additives, including antioxidants, have been utilized in products such as ground beef to increase their shelf life. Therefore, the overall goal of this study was to evaluate the effects of pomegranate rind extract on ground beef color stability and lipid oxidation. Materials and MethodsThe pomegranate rind extract was prepared by mixing dried ground rind powder in boiling water. The mixture was centrifuged to extract the pomegranate rind extract. Course ground beef (80% lean) was mixed with 0, 1, and 1.5% of pomegranate rind extract. The pomegranate rind extract was included into the sample, reground and then formed into a 100 g patty, utilizing the adjust-a-burger patty press. Patties from each treatment were then assigned to 4 different packaging types: PVC, Hi-Ox, CO, and vacuum. Patties packaged in CO and vacuum bags were stored in dark storage 5 d prior to display. The vacuum patties were removed form the bags, packaged in PVC and allowed 1 h to bloom prior to evaluation. Patties packaged in PVC, CO and vacuum were on display for 3 d while patties packaged in Hi-Ox were left on display for 5 d. Patties were evaluated each day by trained color panelists (6 members). Patties were evaluated for display color and surface discoloration. Thiobarbituric acid values were used to indicate lipid oxidation. Lipid oxidation was measured on the control patties on d 0 and then evaluated on all treatments at the end of their assigned display time. The experiments were replicated 6 times (n = 6). The data were analyzed using the Mixed Procedure of SAS, and considered significant at a level of P < 0.05. ResultsDisplay color was brighter cherry red for samples with pomegranate solution compared to the control samples (P < 0.05). Similarly, surface discoloration decreased for patties with the addition of pomegranate solution compared to the controls (P < 0.05). Patties packaged in Hi-Ox maintained color stability longer (P < 0.05) than patties packaged in PVC, CO, and vacuum. There were decreases (P < 0.05) in the lipid oxidation levels of the patties enhanced with 1.0 and 1.5% pomegranate solution compared to the control patties, for all packaging types. Samples enhanced with 1.5% pomegranate solution in vacuum and PVC packaging had 50% less lipid oxidation after display than the control. Similarly, samples with 1.5% pomegranate solution packaged in CO had 65% and Hi-Ox had 75% less lipid oxidation compared to the controls. ConclusionThe use of pomegranate as an antioxidant in ground beef patties had major positive impacts on both color stability and overall freshness (lipid oxidation). The addition of pomegranate will increase the shelf life of ground beef and ultimately decrease the economical loss that results from discoloration of meat.

Ten-year field study of wood plastic composites in Santiago, Chile: biological, mechanical and physical property performance

Outdoor durability of wood plastic composites is a major focus of research and development efforts toward development of more robust building materials. Exterior exposure of wood plastic composites can result in weathering, moisture absorption, fungal and termite attack to various levels of severity depending on the composite formulation. Long-term (> 6 years) field exposure studies of wood plastic composites are lacking in the scientific literature. It is the overall goal of this paper to report on a ten-year field study of wood plastic composites performed in Santiago, Chile. The wood plastic composite formulations were comprised of polypropylene, wood flour, and various additives. Qualitative measurements were made on the stakes each year including the determination of decay and termite ratings on a scale of 1 to 10 as specified in American Wood Preservers’ Association Standards. Surface weathering or discoloration, surface fungi colonization, presence of mold, and/or lichen was noted. The amount of dimensional change (swelling) of the samples in ground contact was determined. Determination of flexural properties of the control and 10-year exposed wood plastic composite stakes were conducted. All the wood plastic composite stake formulations maintained excellent performance ratings after the 10-year field exposure with ratings of 10 for decay and 10 for termites. The wood plastic composites stakes experienced swelling in contact with the soil with the majority of swelling occurring during the first year of exposure. Although the wood plastic composite stakes did well regarding decay and termite performance, the portion of the stakes exposed above ground exhibited various amounts of weathering, surface fungal colonization, and mold and mildew depending on the formulation. Flexural properties of the wood plastic composite stakes decreased or were maintained for the 10-year exposure depending on the composite formulation.

Surgical and Aesthetic Management of Severe Dental Fluorosis Associated with Chronic Generalised Periodontitis: A Case Report

Developmental disturbance of enamel such as dental fluorosis is caused by excessive fluoride on ameloblasts during amelogenesis. Patients are mostly concerned about their aesthetic appearance due to discoloration and loss of tooth structure. These cases are often complicated by poor management of periodontal disease, presenting a challenge during treatment. This case report describes a combination of surgical and aesthetic procedures in management of a severe case of dental fluorosis with brown surface discoloration and small defects combined with chronic generalised periodontitis.

Dentifrices specifically formulated for tooth whitening reduce extrinsic tooth surface discoloration

Dentifrices specifically formulated for tooth whitening reduce extrinsic tooth surface discoloration

358 Effects of rumen protected–histidine supplementation dose on finishing beef cattle

This study examined the effect of dietary rumen-protected histidine (HIS) supplementation in cattle on growth and carcass traits/product quality. Three levels of daily HIS (Balchem Corp.) were tested (control, low dose [DL], and high dose [DH]) over a 55-d finishing period in 48 crossbred steers implanted with Revalor-XS. Cattle were randomly allocated into 8 pens of 6 steers each and fed twice daily using Calan gates. Morning feed was top-dressed with the HIS as follows: control (no HIS), 50 g/steer per day (DL), or 100 g/steer per day (DH). Individual intakes were recorded, and feed and orts were analyzed every 5 d during the feeding period. Steers were harvested, carcass data was recorded, and carcasses were fabricated at a USDA-inspected facility. One longissimus lumborum (LL) and 1 gluteus medius (GM) was acquired from each animal, aged under vacuum (21 and 14 d respectively), and cut into 2.54-cm steaks. One steak was used for retail display for which subjective (to evaluate visual color components) and objective (L*, a*, and b*) color scores were recorded. Lipid oxidation on d 0 and 9 of retail display were assessed using thiobarbituric acid reactive substances. Another steak was used to evaluate cooking loss and tenderness using Warner–Bratzler shear force. Sensory taste panels were conducted (1 panel for each muscle) to determine consumer perception of the product. Muscles were analyzed using HPLC for HIS metabolite (anserine and carnosine) and HIS content. Histidine supplementation increased ADG during d 1 to 21 (DH, P = 0.07), d 42 to 60 (DL and DH, P = 0.07), and the final 50 d (DH, P = 0.07) of feeding. Supplementation with HIS also increased the lightness (DL GM, P = 0.05), degree of yellow hue (DL and DH LL, P = 0.01), oxygenated lean color (DL GM, P = 0.004), uniformity (DH GM, P = 0.03, and DH LL, P = 0.06), and overall color stability of the product from d 3 through 9 of retail display. The percent surface discoloration (DL and DH GM, P = 0.04, and DL and DH LL, P < 0.0001), degree of browning (DL and DH GM, P = 0.002, and DL and DH LL, P < 0.0001), and discoloration (DL and DH GM, P = 0.01, and DH LL, P = 0.05) of the product was decreased. The DL GM steaks were juicier (P = 0.07), more acceptable (P = 0.05), and more satisfying (P = 0.01) than the control steaks. Seventy-seven percent of panelists would purchase the DL GM product (control, 61%, and DH, 60%). In conclusion, 55 d of rumen-protected HIS treatment positively impacts consumer perception and may optimize product quality and marketability in beef cattle.

Microstructure and Surface Damage in Retrieved Metal-on-Metal Hip Arthroplasties

BackgroundBesides promising results of metal-on-metal (MOM) hip arthroplasty (HA), frequent failures have been reported even in the short term. Many host, surgical, design, metallurgical, and processing factors have been evoked in the base of these events. We have tried to characterize and to evaluate metallurgical and processing features present in this type of implants. MethodsThe acetabular and femoral components of 20 MOM HAs collected from a multicenter retrieval program were examined. All the specimens were inspected with naked eye, with confocal microscopy and vertical scanning interferometry, scanning electron microscopy, back-scattered electron imaging, and energy-dispersive X-ray spectroscopy, in 25 zones of each articular component. ResultsGas pores, shrinkage voids and holes of detached carbides, carbides on surface, embedded particles, scratches and marks of wear, surface discoloration, surface deposits, and tribochemical reaction layers were widely dispersed through a substantial percentage of the total bearing surface in all the implanted components. Surface cup and head voids, and cup scratches showed significant correlation with the clearance of pair. A higher surface damage of the cup and head was observed mainly in the low clearance prostheses. There was no other significant correlation or difference in the incidence and importance of any of these defects between resurfacing hip arthroplasties and total hip arthroplasties, or according to the pair diameter. ConclusionSome metallurgical features and surface damage were significantly present in the retrieved implants of MoM HAs. It would be desirable to improve the structure and metallurgical characteristics of these implants to avoid those effects and optimize their performance.

Whitening dentifrice and tooth surface discoloration-a systematic review and meta-analysis.

The aim of this systematic review was to assess the effect of a whitening dentifrice (WDF) relative to a regular dentifrice (RDF) on the reduction of natural extrinsic tooth surface discoloration (ETD). The MEDLINE-PubMed, Cochrane-CENTRAL and EBSCO-Dentistry and Oral Sciences databases were searched, up to April 2017. The inclusion criteria were as follows:(randomized)controlled clinical trials, healthy subjects ≥18years of age, studies comparing WDF with RDF, a follow-up period of at least 6weeks and studies scoring ETD as the stain area/extent, stain intensity or a composite score. Studies using an induced staining model were excluded. Independent screening of 851 unique papers resulted in 21 eligible publications, which included 32 comparisons. The descriptive analysis illustrated that the majority of comparisons showed a significant effect on ETD, in favour of WDF over RDF. The meta-analysis substantiated this observation and revealed that the difference of means (diffM) comparing WDF and RDF was a reduction for stain area of -0.44 [(95% CI: -0.55; -0.339) (P<.00001)] according to the original Lobene Stain Index; this result is in favour of the WDF. For the modified Lobene Stain Index, the diffM was -0.41 [(95% CI: -0.71; -0.10) (P=.009)]. For overall stain intensity, the diffM was -0.35 [(95% CI: -0.44; -0.25) (P<.00001)], and the composite score was -0.39 [(95% CI: -0.57; -0.21) (P<.0001)] and -0.54 [(95% CI: -0.66; -0.43) (P<.00001)]. Subgroup analysis differentiating between products that contained added chemical antidiscoloration agents showed a similar pattern. In this review, nearly all dentifrices that are specifically formulated for tooth whitening were shown to have a beneficial effect in reducing ETD, irrespective of whether or not a chemical discoloration agent was added.

The effect of a tooth/tongue gel and mouthwash regimen on morning oral malodour: A 3-week single-blind randomized clinical trial.

To compare the effects of a regimen consisting of a tooth/tongue gel, tongue cleaner and mouthwash with the effects of using standard fluoride dentifrice on the organoleptic oral malodour score (ORG) and volatile sulphur compounds (VSCs). A total, 66 non-dental students participated in a 3-week parallel, single-blind, randomized, controlled clinical trial. The test group used a tongue cleaner, a tooth/tongue gel and mouthwash containing amine fluoride/stannous fluoride and zinc lactate as oral malodour counteractive. The control group used a standard fluoride dentifrice. Measurements were taken in the morning at baseline, at days 1, 7 and 21. The primary outcome was the ORG score. The secondary outcome, the VSC measurement, was assessed using OralChroma™ (H2 S, CH3 SH, (CH3 )2 S) and Halimeter® . Tongue coating thickness and tongue discoloration were scored. At baseline and day 21, the participants' self-perceptions were assessed. At day 1 for the ORG, H2 S, CH3 SH and Halimeter® readings, a significant decrease was observed in the test group. At day 21, the decrease in H2 S and the Halimeter® outcomes were maintained for the test group, and a significant increase in tongue surface discoloration was observed. The test group evaluated their "morning breath upon awakening" as significantly better (P=.001) after 21days. A significant overnight effect on morning oral malodour was observed for most of the parameters in favour of the test group. At day 21, the effect of prolonged use was significant for H2 S and the Halimeter® readings, although not for the primary ORG outcome parameter.

Chocolate Coating Effect on Whey Protein Isolate-Pullulan-Coated Freeze-Dried Chestnut

Chestnuts are characterized by a limited shelf-life because of their high water content and sugar content hence producers around the world are confronted with a storage problem as product losses are very high. The strategy of the conception, stemming from the current adoption of new food technologies combined with the consumer desirability to put to shelf new products on the market has made researchers and industrialists to upgrade and/or add value to the existing products in order to provide a wider choice of new products to the consumer disposal. The objective of this work was to come up with a suitable technology of extending the shelf-life of harvested chestnut fruits and to develop a new food product for commercial consumption. Whey protein isolate–Pullulan-coated roasted and freeze-dried chestnut (WPI–Pul-RFDC) was coated separately with dark chocolate (DCC) and milk chocolate (MCC). Color change of surface coating and decay incidence were studied at [7°C, 82 ± 5% RH] and [25 ± 2°C, 30 ± 2% RH] for 6 months storage. Further investigation on sensory evaluation were carried out using a taste panel of 120 consumers. 7°C and 25°C provided the best storage conditions for dark chocolate and milky chocolate coating respectively. The results obtained were effective in the control of overgrowth of spoilage organisms and surface discoloration, which is satisfactory in improving the quality and increasing the shelf-life of chestnut. The consumer acceptance testing revealed that chocolate-coating greatly improved the sensory attributes of chestnut as compared to the WPI-Pul coated sample acceptance. This is an alternative strategy to add value to chestnut thus minimizing the significant losses in harvested fruits hence providing a wider choice of new products to the consumer disposal.

Preexisting lesions associated with complete diaphyseal fractures of the third metacarpal bone in 12 Thoroughbred racehorses

We characterized features of complete diaphyseal fractures of third metacarpal bones in Thoroughbred racehorses. Given that stress fractures are known to occur in the third metacarpal bone, an additional aim was to determine if complete fractures are associated with signs of a preexisting incomplete stress fracture. Bilateral metacarpi from 12 Thoroughbred racehorses euthanized because of complete unilateral metacarpal diaphyseal fracture were examined visually and radiographically. Open, comminuted, transverse or short oblique fractures occurred in the middle of the diaphysis or supracondylar region. Periosteal surface discoloration and bone callus formation contiguous with the fracture line were present in fractured bones. All contralateral intact metacarpi had gross anatomic lesions, and 10 had radiographic abnormalities similar to those observed on fractured metacarpi. Catastrophic metacarpal fractures occurred in racehorses with bilateral evidence of preexisting bone injury.

Surface Treatment on Physical Properties and Biocompatibility of Orthodontic Power Chains.

The conventional orthodontic power chain, often composed of polymer materials, has drawbacks such as a reduction of elasticity owing to water absorption as well as surface discoloration and staining resulting from food or beverages consumed by the patient. The goal of this study was to develop a surface treatment (nanoimprinting) for orthodontic power chains and to alleviate their shortcomings. A concave template (anodic alumina) was manufactured by anodization process using pure aluminum substrate by employing the nanoimprinting process. Convex nanopillars were fabricated on the surface of orthodontic power chains, resulting in surface treatment. Distinct parameters of the nanoimprinting process (e.g., imprinting temperature, imprinting pressure, imprinting time, and demolding temperature) were used to fabricate nanopillars on the surface of orthodontic power chains. The results of this study showed that the contact angle of the power chains became larger after surface treatment. In addition, the power chains changed from hydrophilic to hydrophobic. The power chain before surface treatment without water absorption had a water absorption rate of approximately 4%, whereas a modified chain had a water absorption rate of approximately 2%–4%. Furthermore, the color adhesion of the orthodontic power chains after surface modification was less than that before surface modification.

Effects of Temperature Abuse on Shelf Life and Color Stability on Beef Products

ObjectivesMeat color is the single most influential purchasing decision for consumers, as they associate freshness and wholesomeness with discoloration. Surface discoloration results in about 15% of retail beef being discounted and about $1 billion in annual revenue loss. Although several factors can influence beef color, limited information is currently available on the effect of temperature abuse on beef color. Therefore, the overall goal of this study was to evaluate the effects of temperature abuse on shelf-life and color stability in beef products.Materials and MethodsAll master bags (0.4% carbonmonoxide, 30% carbondioxide, and 69.6% nitrogen) were kept in dark storage for 15 d before display at a temperature of –2 to 0°C. Four different treatments were utilized during the 5 d display study: (1) case at –1 to 1°C, 5 d display; (2) case at 3 to 5°C, 5 d display, (3) 8 h temperature abuse at 10°C then 5 d display, case at –1 to 1°C; and (4) 8 h temperature abuse at 10°C and 5 d display, case at 3 to 5°C. Seven trays of strip loin steaks (n = 28) and top sirloin steaks (n = 28) were utilized for each treatment and were randomly assigned to a retail case. Surface color, biochemical, and microbiological qualities were determined during display time. Each sample was visually evaluated for lean color, surface discoloration, and overall acceptability over 5 d by a 6 member trained color panel. For the biochemical analysis, pH, metmyoglobin reducing activity, and oxygen consumption were determined on the steaks before display. At the conclusion of color evaluation, 2 samples from each treatment were utilized for total aerobic plate count. The data were analyzed using the Mixed Procedure of SAS (SAS Inst. Inc., Cary, NC), and considered significant at a level of P < 0.05.ResultsLean color and overall acceptability were not different (P > 0.05) for strip loin and sirloin steaks that were temperature abused prior to display, but lean color and overall acceptability were lower for steaks in warmer retail cases (P < 0.05). Sirloin steak discolored more rapidly (P < 0.05) than strip loin steaks in all treatments. The total plate counts showed no differences between treatments for sirloin steaks. However, a greater total plate count was noted in strip loin steaks that had not been temperature abused but displayed in a warmer temperature. Oxygen consumption rate, metmyoglobin reducing activity, and pH were not different between treatments.ConclusionTemperature abuse prior to retail display had no effect on the lean color, discoloration, or overall acceptability of the product. However, a warmer retail case had significant effect on surface color and overall acceptability of steaks. Temperature abuse prior to display combined with a warmer display case leads to shorter shelf-life.

Relationship between Physiological Maturity and Retail Shelf Life in Heifer Carcasses

ObjectivesOur objective was to determine the relationship between carcass maturity and retail fluid loss, color stability, and lipid oxidation of strip loin and bottom (outside) round steaks.Materials and MethodsRight sides of A (n = 24), B (n = 23), and C (n = 24) maturity heifer carcasses were used. Carcasses under 30 mo of age based on dentition, and with a “small” (Sm) to “moderate” degree of marbling were selected. Beef strip loins (IMPS 180) and outside rounds (IMPS 171B) obtained from these carcasses were purchased from AB Foods (Toppenish, WA) and transported to the University of Idaho Meat Science Laboratory. Following a 14-d aging period, wholesale cuts were removed from vacuum packaging and ischiatic heads were removed from outside rounds to produce trimmed flats. Two 2.54 cm-thick steaks were cut from the trimmed flats and anterior ends of strip loins. One steak was used to measure retail fluid loss and color stability and the other was used to measure lipid oxidation. Steaks were placed in white Styrofoam trays with the freshly cut surface exposed and overwrapped with an oxygen permeable PVC film. Steaks used to determine retail color stability were weighed prior to packaging and displayed in a glass-fronted retail display case at 2.6°C for 6 d. Steaks were allowed to bloom for at least 60 min and then two objective color measurements per steak were taken using a Hunter MiniScan EZ. This represented d 0 of retail display, and subsequent color measurements were taken on d 1, 2, 3, 4, 5, and 6. The instrument was set to illuminant A and Commission International de l’Eclairage (CIE) L*, a*, and b* values were recorded. Three evaluators measured oxygenated lean color, surface discoloration, % discoloration, amount of browning, and color uniformity on each day of retail display. Following 6 d of retail display, steaks were removed from packaging and reweighed to determine retail fluid loss. Thiobarbituric acid reactive substances (TBARS) were quantified in samples obtained from steaks on d 0, 2, 4, and 6 of retail display. Data were analyzed using the Mixed Model procedure of the Statistical Analysis System (SAS Inst. Inc., Cary, NC) and significance was determined at P < 0.05.ResultsMarbling scores of the carcasses were not different across maturity groups (P = 0.79). Average marbling scores were Sm93, Sm99, and Sm98 for A, B, and C maturities, respectively. Heifer carcass maturity did not affect retail fluid loss in either strip loin or bottom round steaks, or color stability of strip loin steaks (P > 0.20). However, the amount of browning in B maturity bottom round steaks was less (P < 0.05) than C maturity steaks. Furthermore, a maturity by day of retail display interaction was observed for bottom round oxygenated lean color (P < 0.001). Lean color of A, B, and C maturity steaks was similar until d 3 of retail display, after which C maturity steaks darkened at a faster rate than A or B maturity steaks. For bottom round steaks, a maturity by day of retail display interaction was observed for TBARS values. Interestingly, lipid oxidation in A versus B and C maturity steaks occurred faster from d 4 to 6 of retail display.ConclusionIn conclusion, advanced skeletal maturity in heifer carcasses under 30 mo of age has little or no negative effect on retail product characteristics.

Nitrite Embedded Vacuum Packaging Improves Retail Color and Oxidative Stability of Bison Steaks and Patties

Bison meat is prone to rapid discoloration under traditional aerobic retail packaging conditions. The aim of this study was to determine if the color stability of bison steaks and burger patties could be improved through packaging meat with a vacuum-sealed film containing embedded sodium nitrite. Bison bulls (n = 40) were slaughtered and the longissimus lumborum (LL) and rhomboideus (RH) were removed. Following a postmortem aging period of 6, 13, or 20 d steaks were obtained from the LL. RH muscles aged 6 d were ground (85:15 lean to fat) and formed into 140 g patties. One steak and two burger patties from each carcass side were placed into either a polystyrene tray overwrapped with oxygen permeable polyvinyl chloride film (CONT) or a polyethylene tray vacuum sealed with film coated in sodium nitrite (113 mg × m–2; NIT); meat was placed under simulated retail conditions for 4 d. A 3-way interaction was observed between packaging type, whole muscle aging and time in retail display for objective (L*, Chroma, and Hue) and subjective (lean color score and proportion of surface discoloration) color measures from steaks (P &lt; 0.0001). The CONT packaged meat showed an increased area of discoloration and in metmyoglobin after 4 d in retail display (P &lt; 0.0001); NIT meats did not show a higher area of discoloration or metmyoglobin after retail display. Additionally, NIT packaged steaks and burger patties lightened (higher L*) and became redder over the course of the retail display period. Thiobarbituric acid reactive substances (products of lipid peroxidation) did not increase in NIT packaged burger patties after 4 d under retail conditions, however, there was a significant increase observed for CONT packaged burger patties (P &lt; 0.0001). NIT packaging appears to effectively improve the color stability of bison meat under retail conditions, making this packaging strategy well suited to address the issue of rapid discoloration.