Introduction: Bilateral absent cortical N20 somatosensory evoked potentials (SSEPs) at 12 and 24 hours after return of spontaneous circulation (ROSC) can predict poor neurologic outcome in cardiac arrest patients. However, it remains unknown if early SSEPs can be used to assess the efficacy of neuroprotective therapies after cardiac arrest. We hypothesized that the rate of SSEP recovery during the first 24 hours after ROSC can differentiate brain injury severity. Methods: Eighteen Yorkshire swine (50-60 kg) were subjected to 5 (VF-5) or 10 minutes (VF-10) of ventricular fibrillation followed by advanced cardiac life support until ROSC. Sham animals were included to control for the effects of sedatives and instrumentation. Bilateral median nerves were stimulated with 35 mA at the forepaws. Cortical signal amplitudes were collected for 1 hour before cardiac arrest (baseline), for the first 4 hours after ROSC, and at 6, 12, 18, and 24 hours after ROSC for 15 minutes at each time point. Two-way ANOVAs were performed to determine inter- and intra-group differences using GraphPad Prism. Results: VF-5 (n= 9) and VF-10 (n=9) animals showed similar and significant N20 suppression from baseline during the first 6 hours after ROSC compared to sham animals (n = 4; Table 1 , Figure 1 ), but both recovered during the first 24 hours after ROSC. VF-10 animals showed trends toward slower N20 recovery compared to VF-5 animals. VF-5 animals demonstrated mean (SD) N20 recovery to 97.1 (33.5)% of baseline by 24 hours after ROSC, whereas VF-10 animals (n= 9) had mean (SD) N20 recovery of 63.9 (28.7)% of baseline by 24 hours after ROSC. Sham animals (n=4) demonstrated the known attenuating effect of Propofol on N20 amplitude to a mean (SD) of 68.9 (15.4)% of baseline by 24 hours after ROSC. Conclusions: Our study demonstrates the feasibility of using serial N20 cortical SSEPs to assess brain function recovery and potentially quantify brain injury severity during the first 24 hours after ROSC in swine cardiac arrest models. Future studies are needed to better understand the impact of prolonged sedation on N20 amplitude and correlate the rate of N20 recovery with blood-based biomarkers and histological findings to confirm the construct validity of early SSEPs in our swine cardiac arrest models.

BACKGROUND Gastroesophageal resuscitative occlusion of the aorta (GROA) has been shown effective in creating zone II aortic occlusion capable of temporarily improving survival in animal models of lethal noncompressible torso hemorrhage. In this study, tandem application of GROA transitioning to resuscitative endovascular balloon occlusion of the aorta (REBOA) is explored to demonstrate feasibility as a potential point-of-injury bridge to more advanced care, using a swine model of lethal abdominal hemorrhage. METHODS Swine (n = 19) were anesthetized, instrumented, and subjected to a combination of controlled and uncontrolled hemorrhage from a grade-V liver laceration. Animals were designated as intervention (n = 9; GROA to REBOA) or control (n = 10), for 60 minutes. Following intervention, devices were deactivated, and animals received blood and crystalloid resuscitation. Animals were monitored for 4 hours. RESULTS Injury resulted in onset of class IV shock in all animals with a mean arterial pressure (SD) of 24.5 (4.11) mm Hg at the start of intervention. Nine of 10 controls died during the intervention period with a median (interquartile) survival time of 8.5 (9.25) minutes. All animals receiving the intervention survived both the 60-minute intervention period demonstrating a significant survival improvement ( p = 0.0007). Transition from GROA to REBOA was successful in all animals with a transition time ranging from 30 to 90 seconds. Mean arterial pressure significantly improved in animals receiving GROA to REBOA for the duration of intervention, regardless of the method of aortic occlusion, with a range of 70.9 (16.04) mm Hg to 101.1 (15.3) mm Hg. Additional hemodynamics, metrics of shock, and oxygenation remained stable during intervention. CONCLUSION Less invasive technologies such as GROA may present an opportunity to control noncompressible torso hemorrhage more rapidly, with a subsequent transition to more advanced care such as REBOA.

Background: Percutaneous ventricular assist device (pLVAD) support and Transient aortic balloon occlusion (AO) can preserve cerebral and cardiac blood flow during cardiopulmonary resuscitation (CPR), but it remains unclear if pLVAD reduces post-cardiac arrest myocardial dysfunction. Hypothesis: pLVAD support immediately after the return of spontaneous circulation (ROSC) improves early recovery of myocardial function following prolonged cardiac arrest. Aims: Evaluate the association between early post-ROSC pLVAD support and recovery of myocardial function in a swine model of prolonged cardiac arrest. Methods: This is a secondary analysis of a subset of animals that achieved ROSC in a study comparing pLVAD, transient AO or both during CPR after prolonged cardiac arrest. pLVAD, aortic occlusion, or both were initiated after 24 minutes of ventricular fibrillation cardiac arrest (8 min no-flow and 16 min mechanical CPR). AO was discontinued post-ROSC, and pLVAD support or standard care were continued. Beginning 60 minutes post-ROSC, pLVAD support was weaned to <1.0 L/min while maintaining a MAP >70 mmHg, and subsequently removed at 4 hours when feasible. The primary outcome was the recovery of cardiac index (CI) and left ventricular ejection fraction (LVEF) at 4 hours post-ROSC. Data are shown as mean (standard error). Results: Seventeen animals achieved ROSC without complication and were included in this analysis (pLVAD group, n = 11 [8 were removed from pLVAD], and standard care group, n = 6). For the primary outcome, the pLVAD group had significantly higher CI of 4.2(0.3) vs. 3.1(0.4) L/min/m2 (p=0.043) and LVEF 60(3) vs. 49(4) % (p=0.029) at 4 hours after ROSC, respectively, when compared with the standard care group. Focusing on the early period within 60 minutes after ROSC when maximum pLVAD flow was maintained, the pLVAD group had significantly higher coronary perfusion pressure (62[4] vs. 47[5] mmHg, p=0.019), lower LV stroke work index (3.9[3.0] vs. 14.9[4.4] cJ/m2, p=0.043), and lower total pulmonary resistance index (13.2[4.8] vs. 21.5[14.4] Wood Unit, p=0.001). Conclusion: These results suggest that early pLVAD support after ROSC is associated with better recovery myocardial function compared to standard care after prolonged cardiac arrest.

Aim: To investigate the effect of tandem use of transient balloon occlusion of the descending aorta (AO) and percutaneous left ventricular assist device (pl-VAD) during cardiopulmonary resuscitation in a large animal model of prolonged cardiac arrest. Methods: Ventricular fibrillation was induced and left untreated for 8 minutes followed by 16 minutes of mechanical CPR (mCPR) in 24 swine, under general anesthesia. Animals were randomized to 3 treatment groups (n = 8 per group): A) pL-VAD (Impella CP & REG;) B) pL-VAD+AO, and C) AO. Impella CP & REG; and the aortic balloon catheter were inserted via the femoral arteries. mCPR was continued during treatment. Defibrillation was attempted 3 times starting at minute 28 and then every 4 minutes. Haemodynamic, cardiac function and blood gas measurements were recorded for up to 4 hours.Results: Coronary perfusion pressure (CoPP) in the pL-VAD+AO Group increased by a mean (SD) of 29.2(13.94) mmHg compared to an increase of 7.1(12.08) and 7.1(5.95) mmHg for groups pL-VAD and AO respectively (p = 0.02). Similarly, cerebral perfusion pressure (CePP) in pL-VAD+AO increased by a mean (SD) of 23.6 (6.11), mmHg compared with 0.97 (9.07) and 6.9 (7.98) mmHg for the other two groups (p < 0.001). The rate of return of spontaneous heartbeat (ROSHB) was 87.5%, 75%, and 100% for pL-VAD+AO, pL-VAD, and AO. Conclusion: Combined AO and pL-VAD improved CPR hemodynamics compared to either intervention alone in this swine model of prolonged cardiac arrest.

Background: Recent studies describe an emerging role for percutaneous ventricular assist devices (pVADs, Impella CP®, Abiomed) as rescue therapy for refractory cardiac arrest (CA). We hypothesized that continuing mechanical chest compressions (mCPR) after initiation of pVAD would improve hemodynamics by decompressing the right ventricle and augmenting pulmonary blood flow and left ventricular filling. We performed a pilot study to test this hypothesis using a swine model of prolonged cardiac arrest. Methods: Eight Yorkshire swine, anesthetized, intubated and instrumented for hemodynamic monitoring, were subjected to untreated ventricular fibrillation for 5.75 (SD 2.90) minutes followed by mCPR for a mean of 20.00 (SD 5.0) minutes before initiation of pVAD (Table 1). After pVAD initiation mCPR was stopped (n=4) or continued (n=4). Defibrillation was attempted 4, 8 and 12 minutes after initiating pVAD circulatory support, except for the first pilot animal where it was attempted at 2 minutes. The animals that achieved return of spontaneous heartbeat (ROSHB) were maintained on pVAD support for four additional hours. Results: There was no difference in the rate of ROSHB between groups (Table 1). The pVAD + mCPR group had significantly higher pVAD flow prior to ROSHB at four- and twelve-minutes after pVAD initiation, and significantly higher end tidal CO 2 (PetCO 2 ) at four- and eight-minutes after pVAD initiation, when compared with the pVAD alone group (Table 1). There was a trend toward higher carotid artery flow prior to ROSHB in the pVAD + mCPR group compared with the pVAD alone group after pVAD initiation, but the difference was not statistically significant (Table 1). Conclusion: The addition of mCPR to pVAD support during cardiac arrest may generate higher pVAD flow and cardiac output prior to ROSHB compared to pVAD alone. Further studies are needed to determine if this approach improves other hemodynamic parameters or outcomes after prolonged cardiac arrest.

Introduction: Invasive mechanical support by percutaneous left ventricular assist device (pL-VAD) and percutaneous balloon occlusion of the aorta (pAO) during CPR have recently emerged as feasible resuscitation strategies for refractory cardiac arrest. It is unknown if combining pL-VAD and pAO has additive or synergist benefits during CPR. Hypothesis: Combined pAO and pL-VAD during CPR will significantly enhance coronary and cerebral perfusion pressure (CoPP, CePP), return of spontaneous heartbeat (ROSHB) rate, and post-ROSHB cardiac function compared to either therapy alone after prolonged cardiac arrest in a swine model. Methods: Nineteen swine 52 (3.9) kg; (9 male) were utilized. A pL-VAD (Impella CP®) and a balloon catheter were inserted through the femoral arteries under general anesthesia. Ventricular fibrillation was induced and left untreated for 8 minutes followed by 16 minutes of mechanical CPR (mCPR). Animals were randomized to 3 treatment groups A) pL-VAD (n=6), B) pL-VAD+pAO (n=6), and C) pAO (n=7). Treatment was initiated 24 minutes after arrest. mCPR was continued during treatment. Defibrillation was attempted 3 times starting at minute 28 and then every 4 minutes. Hemodynamics, cardiac function, and blood gases were monitored for 4 hours after ROSHB. Results: Following the intervention, CoPP for Group B increased by a mean (SD) of 26 (15) mmHg which is significantly different from both groups A and C, 3.6 (12) and 7.5 (6.3) mmHg ( p =0.007). CePP increased by 2 (11.5), 18.5 (18.6), and 8.3 (6.8) mmHg for groups A, B, and C with no significant differences ( p =0.06). The rate of ROSHB was 67% (4 of 6), 83% (5 of 6), and 100% (7 of 7) for groups A, B, and C ( p >0.05). All groups exhibited similar levels of post-ROSHB recovery including blood pressure, venous oxygen saturation, cardiac output, ejection fraction, and lactate clearance. Total ionotropic and vasopressor support (epinephrine and norepinephrine) was 56 (25), 50 (5), and 81 (90) mcg/Kg in groups A, B, and C ( p =0.66). Conclusion: Combined pAO and pL-VAD resulted in greater improvement of CPR hemodynamics compared to either intervention alone in this model of prolonged cardiac arrest. However, it remains unclear if this translates into better recovery of cardiovascular and neurological function.

Beef flavor has been identified as a driver of consumer acceptability; however, little is known about variability of flavor in major United States retail beef cuts. Four beef cuts (chuck roast; top sirloin steaks; top loin steaks; and 80/20 ground beef) were obtained from retail stores (n = 30 per cut per city) in Miami, Los Angeles, Portland, New York, and Denver during a 2-mo period in 2018. Production systems or package claims were documented. An expert trained flavor and texture descriptive attribute sensory panel evaluated beef flavors, aromas, and textures (n =10 cuts per city or 50 cuts evaluated). Consumer sensory panels in Fort Collins, CO (n =10 per cut/city), and Lubbock, TX (n =10 per cut/city), evaluated beef for overall liking, overall flavor, beef flavor, grilled flavor, juiciness, and texture liking. Ground beef patties (GB) were more intense (P G 0.0001) in brown, fat-like, green hay-like, and sour milk/sour dairy flavor aromatics and salty and sweet basic taste than steak or roast cuts. Additionally, GB had the lowest levels (P G 0.0001) of bloody/serumy, metallic, and liver-like flavor aromatics. Chuck roasts had the lowest levels of (P G 0.0001) beef flavor identity, brown, and roasted flavor aromatics and salt and umami basic tastes. Top sirloin steaks were lowest (P G 0.0001) in fat-like flavor aromatics and most intense (P G 0.0001) in burnt, cardboardy, bitter, and sour attributes. Top sirloin steaks and chuck roasts were more intense in metallic and liver-like (P G 0.0001) flavor aromatics. Consumers rated chuck roasts lowest for overall, overall flavor, grilled flavor, and juiciness liking (P G 0.04). GB and top loin steaks had the highest consumer texture liking (P G 0.0002). Beef descriptive flavor and texture attributes were related to consumer liking, and negative flavor aromatic attributes were identified. Variation in beef flavor attributes were reported in retail beef cuts and ground beef that impact consumer liking.

Beef flavor has been identified as a driver of consumer acceptability; however, little is known about variability of flavor in major United States retail beef cuts. Four beef cuts (chuck roast; top sirloin steaks; top loin steaks; and 80/20 ground beef) were obtained from retail stores (n=30 per cut per city) in Miami, Los Angeles, Portland, New York, and Denver during a 2-mo period in 2018. Production systems or package claims were documented. An expert trained flavor and texture descriptive attribute sensory panel evaluated beef flavors, aromas, and textures (n=10 cuts per city or 50 cuts evaluated). Consumer sensory panels in Fort Collins, CO (n=10 per cut/city), and Lubbock, TX (n=10 per cut/city), evaluated beef for overall liking, overall flavor, beef flavor, grilled flavor, juiciness, and texture liking. Ground beef patties (GB) were more intense (P<0.0001) in brown, fat-like, green hay-like, and sour milk/sour dairy flavor aromatics and salty and sweet basic taste than steak or roast cuts. Additionally, GB had the lowest levels (P<0.0001) of bloody/serumy, metallic, and liver-like flavor aromatics. Chuck roasts had the lowest levels of (P<0.0001) beef flavor identity, brown, and roasted flavor aromatics and salt and umami basic tastes. Top sirloin steaks were lowest (P<0.0001) in fat-like flavor aromatics and most intense (P<0.0001) in burnt, cardboardy, bitter, and sour attributes. Top sirloin steaks and chuck roasts were more intense in metallic and liver-like (P<0.0001) flavor aromatics. Consumers rated chuck roasts lowest for overall, overall flavor, grilled flavor, and juiciness liking (P<0.04). GB and top loin steaks had the highest consumer texture liking (P<0.0002). Beef descriptive flavor and texture attributes were related to consumer liking, and negative flavor aromatic attributes were identified. Variation in beef flavor attributes were reported in retail beef cuts and ground beef that impact consumer liking.

Introduction: We previously demonstrated that defibrillation followed by chest compression generates more aerosols than chest compression or no-flow state alone. However, the best strategies to prevent aerosol spread during cardiac arrest (CA) resuscitation remain unknown. We hypothesized that mask applications could reduce aerosol spread during chest compressions and defibrillation in a swine CA model. Methods: To simulate witnessed CA with bystander-initiated CPR, 24 female non-intubated swine (43.8 [2.7] kg) underwent 4 minutes of untreated ventricular fibrillation CA followed by 10 two-minute cycles of mechanical chest compression and defibrillation without ventilation. The animals were randomized to receive no mask, cloth mask, surgical mask, N95 mask, or a sealed nose cone over their snouts during resuscitation (n=5/group except nose cone n=4). The diameter (0.3 - 10 μm) and quantity of particles generated during 45-second intervals of no-flow, chest compression, and after each defibrillation were measured 2 inches anterior to the snout. Results: There were no significant differences between total particles generated during chest compression after defibrillation in unmasked versus masked animals regardless of the mask type, while the nose cone significantly reduced total particles. These findings were consistent across all 10 defibrillations (Fig. 1a) and all particle sizes (Fig. 1b). Furthermore, the minimal pre- and post-defibrillation particles detected outside of the nose cone indicated that the ineffectiveness of masks in preventing aerosol spread during CA resuscitation was likely due to their inadequate fit (Fig. 1c). Conclusion: Mask application did not reduce aerosol spread during defibrillation followed by chest compression in a swine CA model. Our data indicate that mask fit is a critical parameter for reducing aerosol transport and do not support mask application on CA victims during bystander-initiated CPR.

: Beef flavor has been identified as a driver of consumer acceptability; however, little is known about variability of flavor in major United States retail beef cuts. Four beef cuts (chuck roast; top sirloin steaks; top loin steaks; and 80/20 ground beef) were obtained from retail stores (n = 30 per cut per city) in Miami, Los Angeles, Portland, New York, and Denver during a 2-mo period in 2018. Production systems or package claims were documented. An expert trained flavor and texture descriptive attribute sensory panel evaluated beef flavors, aromas, and textures (n = 10 cuts per city or 50 cuts evaluated). Consumer sensory panels in Fort Collins, CO (n = 10 per cut/city), and Lubbock, TX (n = 10 per cut/city), evaluated beef for overall liking, overall flavor, beef flavor, grilled flavor, juiciness, and texture liking. Ground beef patties (GB) were more intense ( P < 0.0001) in brown, fat-like, green hay-like, and sour milk/sour dairy flavor aromatics and salty and sweet basic taste than steak or roast cuts. Additionally, GB had the lowest levels ( P < 0.0001) of bloody/serumy, metallic, and liver-like flavor aromatics. Chuck roasts had the lowest levels of ( P < 0.0001) beef flavor identity, brown, and roasted flavor aromatics and salt and umami basic tastes. Top sirloin steaks were lowest ( P < 0.0001) in fat-like flavor aromatics and most intense ( P < 0.0001) in burnt, cardboardy, bitter, and sour attributes. Top sirloin steaks and chuck roasts were more intense in metallic and liver-like ( P < 0.0001) flavor aromatics. Consumers rated chuck roasts lowest for overall, overall flavor, grilled flavor, and juiciness liking ( P < 0.04). GB and top loin steaks had the highest consumer texture liking ( P < 0.0002). Beef descriptive flavor and texture attributes were related to consumer liking, and negative flavor aromatic attributes were identified. Variation in beef flavor attributes were reported in retail beef cuts and ground beef that impact consumer liking.

This study examined effect of a dietary synbiotic supplement on the concentrations of plasma thyroid hormones, expressions of heat shock protein 70 (HSP70), and intestinal histomorphology in broiler chickens exposed to cyclic heat stress (HS). Three hundred and sixty day old male Ross 708 broiler chicks were randomly distributed among 3 dietary treatments containing a synbiotic (PoultryStar meUS) at 0 (control), 0.5 (0.5×), and 1.0 (1.0×) g/kg. Each treatment contained 8 replicates of 15 birds each housed in floor pens in a temperature and lighting controlled room. Heat stimulation was established from days 15 to 42 at 32°C for 9 h daily. The results indicated that under the HS condition, both synbiotic fed groups had lower liver and hypothalamus HSP70 levels (P < 0.001) compared to control group; however, HSP70 mRNA expression was not different among treatments (P > 0.05). There were no treatment effects on the levels of triiodothyronine (T3) and thyroxine (T4) as well as T3/T4 ratio (P > 0.05). Compared to controls, 1.0× HS broilers had greater villus height in the duodenum (P < 0.01), and greater villus height and villus height:crypt depth ratios in the ileum (P < 0.01). There were no differences among treatments on the measured intestinal parameters in the jejunum (P > 0.05). The results suggest that the synbiotic may ameliorate the negative effects of HS on chicken health as indicated by the changes in the intestinal architecture and the levels of HSP70. Dietary synbiotic supplement could be a feasible nutritive strategy for the poultry industry to improve the health and welfare of chickens when exposed to hot environmental temperature.

ObjectivesConsumer acceptability in meat flavor is one of the driving factors of acceptability. Many studies have found factors that affect beef flavor, but little is known about variability of major beef cuts in the retail meat case where meat is displayed, and customers can choose from.Materials and MethodsFour beef cuts (chuck roast, top sirloin steaks, top loin steaks, and 80/20 ground beef) were obtained from retail stores in Miami, Los Angeles, Portland, New York, and Denver within a 2-mo period. The study wanted a variety of samples that were from different production systems or contained certain claims that would be available to customers. The meat was shipped with dry ice and stored at –9°C. For evaluation steaks, roasts, and ground beef were thawed 24 h at 4°C. Prior to cooking, chuck roasts were cut 10.16 × 12.7cm from the center of the roast. Each ground beef sample was formulated into 3, approximately 150 g patties. Chuck roasts were placed in a roasting pan on a roasting rack and 2 cups of water. Beef steaks and ground beef patties were cooked on a stovetop grill and cooked to 71°C, steaks and patties were flipped when temperature reached 35°F. Chuck roasts were cut into 1.27cm cubes with no visible connective tissue, fat, or outside browning. Steaks were cut into 1.27cm cubes with no connective tissue or fat. Ground beef patties were cut into 6 wedges. Panelists were served either 2 wedges or 2 1.27 cm samples for evaluation. An expert trained descriptive flavor and texture sensory panel was conducted where panelists evaluated beef flavors and textures. Beef flavor and texture attributes were analyzed using SAS (version 9.4, SAS Institute, Inc., Cary, NC) and principal component (PCA) bi-plots were generated using XLSTAT (Addinsoft, Inc., Long Island City, NY) using P < 0.05.ResultsChuck roasts were associated with bloody/serumy flavor aromatics. Ground beef patties were clustered with fat-like, overall sweet, green hay, and buttery flavor aromatics. Top sirloin steaks samples were more highly associated with off flavors such as liver, cardboardy, and sour flavor aromatics. Top loin steaks were clustered with positive attributes such as umami, beef flavor identity, and brown, roasted flavor aromatics. For the PCA biplot, factor 1 accounted for 60% and factor 2 accounted for 28% of variation. Ground beef was higher (P < 0.0001) in brown, fat like, green hay, sour milk/sour dairy, flavor aromatics, and had more salty and sweet basic taste than the other cuts. Ground beef patties had the least amount (P < 0.0001) of bloody/serumy, metallic, and liver like flavor aromatics. Chuck roasts had the least (P < 0.0001) beef flavor id, brown, roasted flavor aromatics and salt and umami basic taste. Sirloin steaks had the lowest (P < 0.0001) fat like flavor aromatic and the highest levels (P < 0.0001) of burnt and cardboardy flavor aromatics and bitter and sour basic taste. Sirloin steaks and chuck roasts had more metallic and liver like (P < 0.0001) flavor aromatics than other cuts. Top loin steaks were intermediate in flavor attributes.ConclusionFlavor descriptive attributes of four beef cuts differed. Results indicated that chuck roasts and top sirloin steaks were associated with negative flavor attributes. Ground beef contained sweeter, fat like attributes with exceptions of green hay, while top loin steaks were associated with more positive beef flavor attributes.

ObjectivesThis study aimed to evaluate the impact of retail display lighting and packaging type on beef flavor and lipid oxidation in five muscles.Materials and MethodsSubprimals (n = 40 strip loins, 60 shoulder clods, 60 tenderloins, 24 inside rounds, 60 top butts) were randomly collected from separate carcasses. At 7d postmortem muscles (Longissimus lumborum, LL; Triceps brachii, TB; Psoas major, PM; Semimembranosus, SM; Gluteus medius, GM) were fabricated and sliced to 2.54cm steaks. Per muscle, 120 steaks were randomly assigned to packaging treatments: vacuum rollstock (ROLL); high-oxygen (80% O2/20% CO2; HIOX); overwrapped in a motherbag with carbon monoxide (0.4%CO/30%CO2/69.6%N2; CO); and traditional overwrap (OW), which was vacuum packaged until immediately prior to display. Packages were stored in the dark at 2°C an additional 13 d prior to retail display, then were displayed under fluorescent lights (FL) or light-emitting diodes (LED) with a third treatment in dark storage (DARK). All were held in their respective light treatments at 2°C for 72h, then assigned for trained panels or chemical analysis, vacuum packaged and frozen at –20°C. For sensory analysis steaks were thawed to 4°C and cooked to 71°C. Panelists (n = 8) were trained to evaluate twelve flavors, overall juiciness and tenderness, which were scored on a 100-point scale (0 = not present; 100 = extremely present). Lipid oxidation of raw steaks was quantified as 2-thiobarbituric acid reactive substances (TBARS; mg malondialdehyde (MDA)/kg beef).ResultsNo three-way interaction (P ≥ 0.10) or lighting effect (P ≥ 0.09) was observed for trained panels or TBARS. Cardboard flavor had a muscle×lighting interaction (P = 0.02). In GM, FL had greater (p < 0.05) cardboard than other lighting; in other muscle types lighting was similar. Muscle×packaging influenced three attributes (P ≤ 0.02). Steaks in ROLL were sweeter (p < 0.05) than other packaging in GM, PM and TB; ROLL was juicier (p < 0.05) than other packaging in GM, PM, and SM. Across all packaging types tenderness was greatest for PM, while SM was least tender (p < 0.05) in CO, HIOX and OW packaging. Packaging influenced nine flavors (P ≤ 0.01); ROLL was greatest in beef ID, bloody/serumy, fat-like, umami, and salty, while HIOX scored greatest for oxidized, bitter, and sour. Brown/roasted was greatest (p < 0.05) in HIOX and CO. Muscle impacted liver-like flavor (P = 0.01), which was lower (p < 0.05) in SM than all other muscle types; LL, TB, PM and GM were similar (p > 0.05) for liver-like. Packaging influenced TBARS (p < 0.01); HIOX had the greatest concentration of MDA, followed by CO, OW and ROLL with the lowest (p ≤ 0.05). Muscle influenced TBARS (P < 0.01), where TB was greatest (p < 0.05), followed by SM, PM, and GM, which were similar (p > 0.05); LL had the lowest MDA concentration. Oxidized (P < 0.01, r = 0.34), cardboard (P < 0.01, r = 0.30), bitterness (P < 0.01, r = 0.23), and sourness (P < 0.01; r = 0.22) were positively correlated with TBARS, while beef ID (P < 0.01, r = –0.23), umami (P < 0.01, r = –0.23), and tenderness (P < 0.01; r = –0.21) were negatively correlated.ConclusionRetail display lighting did not directly influence sensory characteristics or lipid oxidation; lighting only impacted cardboard flavor in an interaction with muscle type. These results suggest after 72h retail display, flavor differences between steaks of similar muscle and packaging displayed under LED or fluorescent lights may not be distinguishable.

The objective of this study was to determine an involvement of heat shock protein (HSPs) in tenderness development of loins from callipyge lambs. Loin samples (M. longissimus thoracis) from sixteen lambs across four genotypes were collected throughout postmortem aging. More intact HSP27 in callipyge was coincided with higher levels of intact desmin and troponin T, less calpain-1 autolysis, and higher shears force values compared to other non-callipyge phenotype lambs (P<0.05). Positive correlations of anti-apoptotic activities (shown by elevated HSP27 and procaspase 3, and less cytochrome c) with increased toughness in callipyge lamb loins were also found (P<0.05). The results from the current study suggest that anti-apoptotic function of HSP would be likely involved in postmortem proteolytic systems and subsequent meat tenderization.

The objective of this study was to determine associations of small heat shock proteins (sHSPs) in tenderness development of loins from callipyge and normal genotype lambs. Loins (M. longissimus lumborum) from sixteen lambs across four genotypes were collected throughout 9 days of postmortem aging. The loins from callipyge lambs had more intact desmin and troponin T throughout aging periods, as well as less μ-calpain autolysis and more calpastatin compared to loins from other genotypes (P < 0.05). Delayed onset of apoptosis was found in the callipyge loins indicated by less cytochrome c and more inactive procaspase-3 compared to normal lamb loins (P < 0.05). Less degraded HSP27 was also consistently found in the callipyge loins compared with loins from normal lambs (P < 0.001). The results found up-regulation of anti-apoptotic activities coincided with toughness in callipyge loins, which suggest apoptosis is likely involved in postmortem proteolysis and subsequent meat tenderization.

The aim of this study was to determine the impact of probiotic feeding and chronic heat stress on meat quality, total lipid and phospholipid contents, lipid oxidation, antioxidant capacity, and heat shock protein abundance of broiler breast muscle. A total of 240 male broilers (5 birds per pen) were subjected to 4 treatments consisting of a 2 x 2 factorial design. Broilers were kept at 21-32-21 degrees C for 10 h daily (heat stress, HS) or 21 degrees C (thermoneutral condition) and fed a regular diet or the diet mixed with probiotic (250 ppm of Sporulin containing 3 strains of Bacillus subtilis). A total of 48 broilers (12 birds/treatment) were harvested at 46 d. Neither HS nor probiotic had substantial impacts on water-holding capacity, shear force, and color characteristics. HS induced lipid oxidation as increased 2-thiobarbituric acid reactive substances (TBARS), in which probiotic feeding decreased TBARS value (P = 0.002) and phospholipid contents (P = 0.0033) in breast muscle of HS broilers. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was increased with HS (P < 0.0001), but no significant impact of probiotic supplementation was found. Neither probiotic nor HS affected catalase activity, but superoxide dismutase and glutathione peroxidase activities were lower in HS broilers compared to thermoneutral controls (P < 0.0001) and in probiotics-fed broilers (P < 0.0001) compared to their counterparts. In addition, a significant interaction between probiotic and HS was found at glutathione peroxidase activities, in which breast muscle of broilers fed probiotic at thermoneutral condition showed the highest activity (P < 0.05). Regarding heat shock protein (HSP) determination, HS slightly increased the levels of both HSP70 (P = 0.08) and HSP27 (P = 0.05), but no significant impacts of probiotic supplementation were found. Our results indicate that probiotic feeding could improve breast muscle weight without adverse impacts on meat quality attributes, as well as alleviate oxidative deterioration of breast muscle of broilers undergoing heat stress.

This study aimed to determine the influence of finishing diet on beef appearance and lipid oxidation of three beef muscles. A total of 18 Angus steers were selected from three diet treatments: grass-finished (USUGrass), legume-finished (USUBFT), and grain-finished (USUGrain). After processing, longissimus thoracis (LT), triceps brachii (TB), and gluteus medius (GM) steaks were evaluated over a 7-d display period. A muscle × diet interaction was observed for instrumental lightness (L*) and redness (a*) (P ≤ 0.001). Within each combination, USUGrass was considered darker with lower (P < 0.05) L* compared with USUGrain. For USUBFT, L* was similar to USUGrain for the TB and LT, while the L* of USUBFT and USUGrain GM differed (P < 0.05). In terms of redness, LT a* values were elevated (P < 0.05) in USUGrass compared with USUBFT and USUGrain. For GM steaks, a* of USUBFT and USUGrass were each greater (P < 0.05) than USUGrain. Surface a* of TB steaks were greatest (P < 0.05) for USUGrass followed by USUBFT, and with USUGrain, being lowest (P < 0.05). An overall increase in L* was observed throughout display dependent on diet (P = 0.013). During display, USUGrain steaks had the greatest (P < 0.05) L* followed by USUBFT and USUGrass. Additionally, a day × muscle interaction was observed for a* (P = 0.009). Initially, TB steaks had the greatest (P < 0.05) a* values. However, at day 3, a* values were similar (P > 0.05) among muscles. Visual color scores were in agreement with loss of redness (a*) during display, dependent on diet and muscle type (P < 0.001). Similarly, a day × diet × muscle interaction was observed for visual discoloration (P < 0.001). Day and diet interacted to influence thiobarbituric acid reactive substances (TBARS) (P < 0.001). Initial values did not differ (P > 0.05) between USUGrain and USUBFT; however, USUGrass had lower initial (P < 0.05) TBARS than both USUGrain and USUBFT. At days 3 and 7, TBARS were greatest (P < 0.05) in USUGrain steaks, followed by USUBFT, which was greater (P < 0.05) than USUGrass. A diet × muscle interaction was observed for 10 volatile compounds originating from lipid degradation (P ≤ 0.013). These compounds were less (P < 0.05) abundant in USUGrass compared to TB or GM of USUGrain. This study determined grass-finished beef to have a darker more red color and less lipid oxidation in multiple muscles. Possible mechanisms for this may include an increase in endogenous antioxidants in grass-finished beef.

ObjectivesThe goal of this study was to evaluate the impact of 4 packaging types and 2 retail lighting systems on objective measures of microbial growth and muscle color of beef Longissimus lumborum steaks.Materials and MethodsBeef strip loins (n = 8), USDA Choice, were collected and fabricated (7d postmortem) into seventeen 1.27-cm thick steaks. Steaks (n = 16) were assigned into 4 packaging treatments: high oxygen MAP (80% O2, 20% CO2) (HIOX), overwrapped packages in a motherbag flushed with carbon monoxide (0.4% CO, 30% CO2, 69.6% N2) (CO), vacuum rollstock (VAC), and traditional overwrap (OW), which were held in vacuum packaging, then placed onto foam trays and sealed with polyvinyl chloride film immediately before display. Microbial sampling occurred for each treatment at 7d (packaging), 20d (before display), and 23d (post display) postmortem. Each package type was sorted into 3 lighting treatments: darkness (DARK) (put in a box and held in cold storage), or a refrigerated open multi-deck retail display case with either light emitting diode (LED) or fluorescent (FL) lighting for 72h. Instrumental color (L* a* b*) was measured, and chroma calculated, at 0h and 72h of display using a Hunter Colorimeter. Aerobic Plate Counts (APC) and Psychrotrophic Plate Counts (PPC) were evaluated at packaging day, 0h and 72h retail display. Bacterial load was determined by swabbing a 50 cm2 area of the steak. Serial dilutions were plated, in duplicate, onto APC petrifilm for mesophilic incubation, and standard methods agar plates for psychrotrophic incubation. Bacterial counts were reported as log10 CFU/50 cm2. Microbial data were analyzed using the GLM procedure of SAS 9.4 (SAS Inst. Inc., Cary, NC), and color analysis performed using the GLM procedure with repeated measures to account for beginning and end of retail display. Statistical significance was determined at P ≤ 0.05.ResultsThere were no interactions between lighting and packaging type for APC or PPC (P > 0.05). Mean APC differed by sampling time, from 0.77 log10 CFU/50cm2 on packaging day to 3.79 log10 CFU/50 cm2 at the end of retail display (P < 0.0001) across all packaging types. At the end of display, mean APC from OW were greater than HIOX packages, 3.83 and 3.05 log10 CFU/50 cm2 respectively (P < 0.05). Lighting did not impact APC counts at the end of display across any packaging type (P = 0.84). Lighting across all packaging types did not significantly (P = 0.07) impact PPC. Psychrotrophic means differed among VAC, CO, OW and HIOX (P < 0.05) ranging from 5.52 to 6.87 log10 CFU/50 cm2, with HIOX and CO being the only 2 packaging types that were not different (P > 0.05.) At the end of display, across all packaging types, L* values differed (P < 0.05) between FL display (34.20) and DARK (36.69) packages. Calculated chroma, a* and b* did not vary (P > 0.05) between lighting treatments across package types at the end of retail display.ConclusionThis study provides evidence that packaging type has more of an effect on bacteria than lighting conditions, and variability in the lighting conditions does not have an impact on calculated chroma, b* or a* values, but does affect brightness (L*). Overall, OW packages had greater APC and PPC. These results imply packaging type may be used as a way to improve shelf life via control of spoilage bacteria. Moreover, this study indicates lighting systems may be used interchangeably when considering growth of spoilage organisms.

ObjectivesThis study aimed to evaluate various packaging methods and retail display lighting conditions on the consumer preference of steaks from 5 different muscles.Materials and MethodsSubprimals (n = 40 strip loins, 60 shoulder clods, 60 tenderloins, 60 top butts, 24 inside rounds) were collected from USDA choice beef carcasses and shipped to Texas Tech University. At 7d postmortem muscles (Longissimus lumborum, LL; Triceps brachii, TB; Psoas major, PM; Semimembranosus, SM; Gluteus medius, GM) were fabricated and sliced into 1 in steaks. Steaks (n = 120 per muscle) were randomly assigned to 4 packaging treatments: vacuum rollstock (ROLL); high-oxygen modified atmosphere (80% O2/20% CO2; HIOX); traditional overwrapped and stored in a motherbag with carbon monoxide (0.4% CO/30% CO2/69.6% N2; CO); and traditional overwrapped (OW), which was vacuum packaged until immediately prior to display. Steaks were stored an additional 13 d prior to retail display; they were displayed under fluorescent lights (FL) or light-emitting diodes (LED), with a third treatment remaining in dark storage (DARK). Steaks were displayed for 72h and then individually vacuum packaged. Steaks were cooked to a medium doneness and consumers (n = 300) rated flavor, juiciness, tenderness, and overall liking. Significant (P = 0.05) 3-way interactions were evaluated as slices of package×light interactions within each muscle types.ResultsA packaging×light interaction influenced flavor liking (P = 0.02). Dark storage improved flavor liking in OW and CO compared with FL for those treatments (P < 0.05). Rollstock had greater flavor liking scores than other packaging treatments among FL and LED display (P < 0.05). For packages placed under dark storage, HIOX had the lowest (P < 0.05) flavor liking. Muscle type influenced flavor liking (P < 0.0001), with PM being more liked (P < 0.05) than all other muscles. The SM had the lowest (P < 0.05) flavor liking compared to all other muscles. A muscle×packaging×light interaction was observed for juiciness liking (P = 0.0003). For GM steaks, each packaging type displayed under FL had the greatest (P < 0.05) juiciness liking. For the SM, HIOX had less (P < 0.05) juiciness than ROLL under FL display. Under LED display SM HIOX was lower (P < 0.05) in juiciness compared with SM CO. Tenderness liking also showed a muscle×packaging×lighting interaction (P = 0.002). In GM ROLL-DARK was less (P < 0.05) tender than ROLL-FL and ROLL-LED, which did not differ (P > 0.05). For LL, CO was more tender (P < 0.05) than HIOX steaks under FL display. Within SM, ROLL-DARK had similar (P < 0.05) tenderness as OW-DARK and each were more (P < 0.05) tender than all other packaging and lighting treatments. In TB, OW-FL had greater (P < 0.05) tenderness than all other TB steaks under FL display. The TB ROLL-LED and CO-LED were more (P < 0.05) tender than each other packaging type under LED display. A muscle×lighting interaction influenced overall liking (P = 0.05), where consumers liked PM most (P < 0.05) and SM least (P < 0.05), regardless of lighting treatment.ConclusionThis study indicates that both lighting and packaging influence palatability of multiple beef muscles. Therefore, specific environments may be selected which lend to greater palatability.