Metaphylactic antimicrobial effects on occurrences of antimicrobial resistance in Salmonella, Escherichia coli, and Enterococcus spp. measured longitudinally from feedlot arrival to harvest in high-risk beef cattle

Aims

Our objective was to determine how injectable antimicrobials affected populations of Salmonella enterica, Escherichia coli and Enterococcus spp. in feedlot cattle.

Methods and Results

Two arrival date blocks of high‐risk crossbred beef cattle (n = 249; mean BW = 244 kg) were randomly assigned one of four antimicrobial treatments administered on day 0: sterile saline control (CON), tulathromycin (TUL), ceftiofur (CEF) or florfenicol (FLR). Faecal samples were collected on days 0, 28, 56, 112, 182 and study end (day 252 for block 1 and day 242 for block 2). Hide swabs and subiliac lymph nodes were collected the day before and the day of harvest. Samples were cultured for antimicrobial‐resistant Salmonella, Escherichia coli and Enterococcus spp. The effect of treatment varied by day across all targeted bacterial populations (p ≤ 0.01) except total E. coli. Total E. coli counts were greatest on days 112, 182 and study end (p ≤ 0.01). Tulathromycin resulted in greater counts and prevalence of Salmonella from faeces than CON at study end (p ≤ 0.01). Tulathromycin and CEF yielded greater Salmonella hide prevalence and greater counts of 128ERY^RE. coli at study end than CON (p ≤ 0.01). No faecal Salmonella resistant to tetracyclines or third‐generation cephalosporins were detected. Ceftiofur was associated with greater counts of 8ERY^REnterococcus spp. at study end (p ≤ 0.03). By the day before harvest, antimicrobial use did not increase prevalence or counts for all other bacterial populations compared with CON (p ≥ 0.13).

Conclusions

Antimicrobial resistance (AMR) in feedlot cattle is not caused solely by using a metaphylactic antimicrobial on arrival, but more likely a multitude of environmental and management factors.

Impact of Packaging and Muscle Type on Beef Flavor Development

ObjectivesThe objective of this study was to determine the influence of packaging type on production of beef flavor volatile compounds.Materials and MethodsBeef strip loins (IMPS #180) and top sirloin butts (IMPS #184) were selected from USDA Low Choice carcasses (n = 40, 20/subprimal). Seven d postmortem, subprimals were fabricated into 2.54 cm representative steaks of the Longissimus lumborum (LL) and Gluteus medius (GM). Steaks were then placed into one of four randomly assigned packaging treatments: carbon monoxide motherbag (0.4% CO/30% CO2/69.6% N2; CO), high oxygen modified atmosphere packaging (80% O2/20% CO2; HIOX), traditional polyvinyl chloride overwrap (OW), and rollstock (ROLL). Steaks designated for the OW treatment were placed in ROLL treatment until retail display. Steaks were aged in the absence of light for 14 d, then subjected to a 48-h retail display under fluorescent lighting in coffin cases. Following retail display, steaks were immediately vacuum packaged and frozen at –20°C until further analysis. Prior to volatile compound analysis, steaks were thawed at 2–4°C. Steaks were then cooked to 71°C using clamshell grills. Immediately after cooking, six 1.27 cm cores were removed, then minced using a coffee grinder. Five g of sample was weighed into a glass vial, sealed, then analyzed using gas chromatography-mass spectrometry. Compounds evaluated were chosen from major flavor pathways.ResultsThree compounds, carbon disulfide, 2-pentylfuran, and benzaldehyde elicited a packaging type × muscle interaction (P ≤ 0.048). Carbon disulfide was present in the highest concentration (P < 0.05) in CO GM and ROLL LL steaks, but was present in the lowest amount (P < 0.05) in OW GM and ROLL GM steaks. For benzaldehyde, HIOX GM steaks produced the greatest concentration (P < 0.05) compared to all other treatments, with the exception of ROLL LL, which was similar (P > 0.05). A similar trend existed for 2-pentylfuran, as high oxygen GM steaks produced over three times higher concentrations (P < 0.05) of 2-pentylfuran compared to all other treatments. Nine compounds, primarily lipid derived, were impacted by a packaging main effect (P < 0.043). For 2-propanone, pentane, and hexanoic acid, methyl ester, HIOX packaging produced the greatest concentration (P < 0.05) compared to all other treatments. Additionally, HIOX steaks produced a greater amount (P < 0.05) of methanethiol than OW or ROLL steaks. High oxygen steaks produced more (P < 0.05) 1-pentanol, 1-octen-3-ol, and nonanal than CO steaks, but were similar to ROLL and OW steaks. Carbon monoxide packaging produced the greatest amount (P < 0.05) of 2,3-butanediol compared to all other treatments. Five compounds were impacted by the muscle main effect (P ≤ 0.039). The GM steaks produced a greater concentration of 2,3-butanedione (P = 0.011), 3-hydroxy-2-butanone (P = 0.002), octanoic acid (P < 0.001), and dodecanal (P = 0.021) than the LL steaks. The LL produced a greater amount of decanal (P = 0.039) than the GM.ConclusionThese results indicate packaging and muscle each impact flavor, however, packaging effects are primarily lipid derived and muscle more readily impacts Maillard product production. Additionally, HIOX packaging produces a large amount of lipid derived compounds from degradation and oxidation, which may form the basis for its negative flavor profile. This indicates HIOX packaging should be avoided to produce more positive flavor notes in beef.

Retail Display Lighting and Packaging Type May Influence Beef Flavor and Oxidative Stability

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.

Effects of Extended Aging on the Flavor Characteristics of Grass and Grain Fed Australian Beef Longissimus Thoracis

ObjectivesThe objective of this study was to investigate the effects of extended wet ageing on the flavor characteristics, of grass and grain fed Australian beef lumborum thoracis.Materials and MethodsCube rolls (HAM #2244) were collected from grass and grain fed cattle (n = 30) at a commercial abattoir near Brisbane, Australia. Cube rolls were vacuum packaged and shipped under refrigeration (0–2°C) to Texas Tech University. Each cube roll was cut into 2.5-cm steaks and labeled according to position from posterior to anterior end. Steaks were vacuumed packaged, stored through the appropriate postmortem ageing period (35, 45, 55, or 65 d postmortem), and then frozen until further analysis. One steak from each cube roll was used for trained descriptive flavor analysis with 8 trained panelists comprised of mostly graduate students from Texas Tech University. Flavor attributes of cooked steaks were scored using 100-point anchored line scales (0 = none, 50 = moderate, and 100 = strong).Data were analyzed used PROC GLIMMIX of SAS with diet, postmortem ageing, and their interaction as fixed effects and panelist as a random effect. Final temperature was tested as a covariate for all the flavor attributes.ResultsAn interaction was detected only for the bitter flavor and overall juiciness (P ≤ 0.03). Beef flavor ID, fat-like, metallic, umami, and sweet were not influenced by diet or postmortem ageing (P > 0.05). Ageing influenced bloody serumy flavor (P > 0.05) with 45 d samples having greater flavor than 55 d samples, but not differing (P > 0.05) from any other ageing period. Diet and ageing influenced rancid flavor (P > 0.05), with grass fed samples having a stronger rancid flavor than grain fed samples. Samples aged 65 d had a stronger rancid flavor than 45 or 55-d samples, and 35-d samples had the lowest rancid flavor. Diet and ageing influenced grassy flavor (P > 0.05), again being stronger in grass than grain fed samples. Samples aged 35 d had a weaker (P > 0.05) grassy flavor than any other ageing period, which did not differ (P > 0.05). Diet and ageing had an effect on liver-like flavor (P < 0.05) with stronger flavors in grain than grass fed samples and liver-like flavor increasing with postmortem ageing time. Sour flavor was affected by diet only (P < 0.05) with grass fed samples having stronger sour flavor than grain fed samples. Ageing had an effect on overall tenderness (P < 0.05); samples aged 35 d were least tender, and samples aged 45 d were more tender than 55 d samples but did not differ from 65 d samples.ConclusionThe results suggest that beef flavor as measured by beef flavor ID and umami were not impacted by extended ageing; however, some off-flavors grew stronger as ageing time extended. Flavor attributes such as rancid, grassy, sour were stronger in grass than grain fed samples, but grain fed has a stronger liver-like flavor. Ageing influenced both overall tenderness and juiciness, but typically not in a linear fashion.

Volatile Compounds of Lamb Longissimus and Semimembranosus from Australia, New Zealand, and the United States

ObjectivesDifferences in production practices based on country of origin create distinct differences in palatability of lamb from both the loin and the leg. The objective of this study was to identify volatile compounds which influence flavor across lamb leg and loin chops sourced from three countries of origin.Materials and MethodsLamb loins (IMPS #232 1 × 1; n = 30/treatment) and legs (IMPS #233A; n = 60/treatment) were sourced from Australia (AUS), New Zealand (NZ), and the United States (US). Product was fabricated to isolate the longissimus lumborum (LL) from the loins and the semimembranosus (SM) with adductor from the legs. Muscles were trimmed of external fat and connective tissue and fabricated into 2.54-cm thick chops, vacuum packaged individually, and frozen. A subset of samples (n = 15/treatment) for volatile compound analysis were thawed at 2–4°C for 24 h, cooked to a medium degree of doneness, frozen, and powdered. Volatile compounds were extracted via SPME from powdered samples and analyzed using GC–MS. Data were analyzed as a 2 × 3 factorial design with muscle, country of origin (COO), and their interaction as fixed effects with a significance level of α = 0.05.ResultsDifferences in volatile compounds of all classes were largely related to COO. Of the 36 lipid-derived compounds, 18 were affected by COO (P < 0.05) and 11 were affected by the interaction of muscle and COO (P < 0.05). Where the interaction was significant, US LL and SM samples generally produced greater concentrations of volatile compounds than other treatments (P < 0.05), especially in compound classes including alcohols, n-aldehydes, and ketones. Of the alkanes evaluated, only pentane was greater in US samples compared to other samples (P < 0.05) and was more than double the concentration produced in NZ and AUS samples. Alkenes did not follow the general trend of being increased in US samples. P-xylene was elevated in SM samples compared to LL samples (P < 0.01), and toluene was greater in NZ samples than US and AUS samples (P < 0.05). D-limonene was decreased in AUS samples compared to US and NZ samples. Of the 18 Maillard-derived compounds identified, 13 were affected by COO (P < 0.05), 3 were affected by muscle (P < 0.01), and 3 were affected by the interaction of COO and muscle (P < 0.05). Of the Strecker aldehydes, 3-methylbutanal and 2-methylbutanal were both affected by both COO (P < 0.01) and muscle (P < 0.05). US samples produced the greatest concentration of these compounds (P < 0.05) and AUS samples produced the least (P < 0.05). Samples from LL produced more of these compounds than SM samples (P < 0.05). Ketones including acetoin and 2,3-butanedione, which contribute positively to flavor in meat, were highly elevated in US samples compared to AUS and NZ (P < 0.05). Sulfur-containing compounds were generally greater in non-domestic product than US samples, except for dimethyl sulfide, which was greatest in US SM samples and least in NZ LL and AUS SM samples (P < 0.05). Pyrazines were generally elevated in NZ samples compared to AUS samples (P < 0.05), with US samples intermediate (P > 0.05).ConclusionCountry of origin is a strong influencer of flavor compounds in lamb. This is likely attributable to global differences in production system including, but not limited to, diet, genetics, sex, and postmortem handling and will influence the perception of flavor by consumers.

Effects of Dry Heat Cooking Method and Quality Grade on the Composition and Objective Tenderness and Juiciness of Beef Strip Loin Steaks

ObjectivesThe objective of this study was to evaluate instrumental measures of tenderness and juiciness of beef strip loin steaks representing four different USDA quality grades cooked using four dry heat cooking methods.Materials and MethodsStrip loins (n = 12/quality grade) were collected from four USDA quality grades [Prime, Top (upper 2/3) Choice, Low (lower 1/3) Choice, and Select]. At 21 d postmortem, strip loins were cut into 2.5 cm thick steaks and stored at –20°C until analysis. The most anterior steak was used for compositional analysis and every three adjacent steaks were grouped and assigned randomly to one of four different dry heat cooking methods [electric clamshell grill (CLAM), flat-top gas grill (FLAT), charbroiler gas grill (CHAR), and salamander gas broiler (SAL)]. Objective measures for raw samples included proximate composition and for cooked samples included cooking loss, pressed juiciness (PJP), and slice shear force (SSF) after the sample was cooked to a medium degree of doneness (70–72°C). In addition, consumers assessed attributes for each sample on an electronic ballot with a 100-point continuous line scale for juiciness, tenderness, flavor liking, and overall liking. Proximate data were analyzed using the GLIMMIX procedure of SAS with quality grade as the fixed effect. All other data were analyzed as split-plot design with quality grade as a whole plot factor, the strip loin as the whole plot unit, and cooking method as a subplot factor.ResultsUSDA Quality grade influenced fat, moisture, and protein percentage (P < 0.01). As expected, there was a fat percentage difference (P < 0.05) between each grade with a decline from Prime to Select samples. Therefore, Select had a greater (P < 0.05) moisture percentage than any other quality grade, and an inverse relationship was observed as there was an increase in moisture between each grade from Select to Prime (P < 0.05). Select and Low Choice had greater (P < 0.05) protein percentage than Top Choice or Prime, which were similar (P > 0.05). As expected, an inverse relationship between increased marbling levels and decreased SSF scores were also observed resulting in a negative correlation between fat and objective tenderness (r = –0.15; P < 0.05). In addition, fat was positively associated with consumer palatability scores (r ≥ 0.21; P < 0.01). Cooking method influenced (P < 0.01) cooking loss, but did not impact SSF or PJP (P ≥ 0.19). CLAM had lower (P < 0.05) cooking loss than FLAT, SAL, and CHAR, which did not differ from each other (P > 0.05). The lower cooking loss of CLAM could be related to the shorter cooking times compared to the other methods. Pressed juiciness percentage was not influenced by quality grade, cooking method, or their interaction (P ≥ 0.19) and was not related to any objective or subjective measures of palatability (P > 0.05). Slice shear force was not influenced by quality grade, cooking method, or their interaction (P ≥ 0.15); however, SSF was related (r ≤ 0.18; P < 0.05) to tenderness, juiciness, flavor and overall liking.ConclusionIn the current study, quality grade influenced the composition of raw samples, yet, quality grade coupled with different dry heat cooking methods did not influence objective measures of tenderness or juiciness.

Sensory Descriptive Attributes of Grass and Grain-Fed Australian Beef Longissimus Lumborum after Extended Wet-Aging Periods

ObjectivesThe objective of this study was to evaluate the effects of extended wet-aging on the beef flavor profile of grass and grain-fed Australian strip loins.Materials and MethodsStrip loins (HAM 2140) were collected from grass and grain finished cattle (n = 50) at a commercial abattoir near Brisbane, Australia. Subprimals were portioned into sections and assigned randomly to 1 of 3 postmortem aging periods (45, 70, or 135 d). Portions were individually vacuum packaged and shipped refrigerated (0–4°C) to Texas Tech University in Lubbock, TX. Upon arrival, the strip loin sections were sorted into respective aging groups of 45D, 70D, and 135D and stored at 1–2°C. On each respective day, sections were fabricated into 2.54-cm steaks, vacuum packaged and frozen (–21°C). Electric clamshell grills were used to cook thawed (held at 2–4°C for 24 h) steaks to a medium degree of doneness (71°C); cooked temperatures were recorded. Steaks were cut into cubes and evaluated by trained panelists (n = 6) for descriptive sensory attributes using a 100-mm anchored line scales (0 = slight, 50 = moderate and 100 = strong).ResultsThe sour flavor was the only trait where an interaction between diet and postmortem aging was detected (P < 0.01). Samples aged 135 d from both grass and grain were similarly (P > 0.05) scored with a stronger (P < 0.05) sour flavor than all other treatment combinations, which did not differ (P > 0.05). Aging impacted (P ≤ 0.01) beef flavor ID, liver-like, metallic, rancid, green-hay, umami, and bitter flavors, as well as overall juiciness and overall tenderness. For beef flavor ID, 45D aging resulted in the greatest intensity (P < 0.05), while 70D samples were intermediate, and 135D samples were the least intense. For liver-like, metallic, rancid, green-hay, and bitter flavors, 135D samples had the strongest flavor, while 70D samples were intermediate, and 45D samples had the weakest flavor intensity (P < 0.05). For umami, 45D samples had stronger (P < 0.05) umami flavor than 135D samples, but 70D samples did not differ from either 45D or 135D (P > 0.05). Panelists rated 70D and 135D samples juicier (P < 0.01) than 45D samples, but 70D and 135D did not differ (P > 0.05). For overall tenderness, panelists rated 135D samples more tender (P < 0.05) than 45D and 70D, which were similar (P > 0.05). Diet impacted (P < 0.05) bloody/serumy, liver-like, green-hay, and bitter flavors. For bloody/serumy and liver-like, the grain fed treatments resulted in greater (P < 0.05) flavor intensity than grass fed treatments. However, grass fed samples had stronger (P < 0.05) green-hay and bitter flavors compared to grain fed samples. Diet and aging had no effect (P > 0.05) on fat-like or sweet flavors.ConclusionExtending postmortem aging of Australian beef strip loins from 45 to 135 d resulted in decreased beef and umami flavors, along with concurrent increased detection of off-flavors, such as liver-like, rancid, and sour. Diet influenced fewer flavor traits than postmortem aging, but grass-fed samples still had stronger green-hay flavor, as would be expected. Based on these results, aging beef strip loins 135 d is not recommended based on reduced beef flavor and increased off-flavor detection.

Impacts of Various Dry-Aging Methods on Meat Quality and Palatability Attributes of Beef Loins from Cull Cow

ObjectivesBeef from cull cows has been traditionally perceived as low-quality/value meat due to its inferior flavor and tenderness. Given the negative consumer perception of highly processed fresh meat, there is a need to develop a natural post-harvest aging system to improve eating quality attributes of beef products, particularly from cull cows. Dry aging has been practiced for decades as a traditional and natural butchery process, which is also known to improve palatability characteristics. Thus, the main objective of this study was to evaluate the impact of different dry-aging methods on meat quality, microbiological properties and palatability attributes of loins from cull cow beef.Materials and MethodsPaired beef loins from 13 carcasses (Holstein, 30+ mo) were obtained at 5d postmortem, divided into 4 equal length sections and randomly assigned to four aging methods: wet-aging (WA), dry-aging (DA), dry-aging in water permeable bag (DWA) and UV-light dry-aging (UDA; 2 treatment/day, 5 J/s/treatment). Sections were aged for 28d at 2°C, 65% RH and 0.8 m/s air flow. After aging, dry-aged sections (DA, DWA and UDA) were trimmed of dehydrated surface, and trim loss and total saleable yield were recorded. The pH, proximate composition, shear force, water-holding capacity, initial color (instrumental and trained panelist), lipid oxidation (2-thiobabituric acid reactive substances, TBARS), microbial properties (aerobic plate count (APC), lactic acid bacteria (LAB), and yeast and mold (YM) counts) and trained sensory evaluation (11 panelists) were determined. Experimental design was a balanced complete block design. All data were analyzed using PROC MIXED procedure of SAS, and least squares means for all traits were separated (P < 0.05).ResultsDA and UDA had a substantial moisture loss during the aging process, accompanied with higher trim loss compared to other methods (P < 0.05). This resulted in DA having the lowest yield followed by UDA, DWA and WA with the highest saleable yield (P < 0.05). No significant differences were observed on cook loss, WBSF and TBARS between the treatments. DWA had the lowest pH out of all treatments (P < 0.05). UDA had the lowest moisture content and highest drip loss (P < 0.05). Color measurement showed that both DA and WA had significantly higher L* and lower b* values compared to UDA and DWA (P < 0.05). However, a* and lean surface color were not significantly different between the treatments (P > 0.05). For the trim, UDA had the lowest microbial growth among all treatments (P < 0.05). For the lean, UDA had the lowest count for LAB (P < 0.05), WA had the lowest in YM (P < 0.05) and no difference was found for APC between treatments (P > 0.05). Trained sensory panelist found that UDA and WA had higher fat and sour flavor (P < 0.05), and a trend (P = 0.07) of higher oxidized flavor when compared to DWA and DA.ConclusionThe results showed that dry-aging would result in no adverse impact on shear force, cooking loss, initial color and lipid oxidation of mature beef loins. Further, sour and oxidized flavor was lower in dry-aged beef, indicating its potential as value adding process. UV light application minimized microbial growth during dry-aging process, although more analyses are needed to understand its full impact on dry-aged meat quality. Further studies on determining the consumer acceptability as well as flavor-related compound analyses are currently under investigation.

The Effect of Grain and Grass Fed Beef and Chicken Breast Consumption on the Functional Connectivity in the Brain Using Resting State Functional Magnetic Resonance Imaging

ObjectivesUnderstanding functional connectivity after consuming meat can be essential to fully understanding consumer’s preferences and the connection to certain flavor compounds. The objective of this study was to determine differences in the functional brain connectivity of consumers after consuming grass-fed beef, grain-fed beef and chicken while determining the different chemical and volatile components that differentiate the treatments.Materials and MethodsGrass-fed strip steaks, Grain-fed strip steaks and chicken breasts were collected, aged 21 d and cut into 1×1-inch consumer steaks. Each steak was vacuum sealed with a random identification number and frozen at –20°C. 23 volunteered consumers evaluated each treatment randomly followed by a Blood Oxygen Level-Dependent (BOLD) fMRI scan. Each consumer received a resting state scan and three scans following each sample. The beef was cooked to a medium degree of doneness (71°C) and the chicken was cooked to a well-done degree of doneness (75°C), followed by a 1-min resting period. The consumers were asked to complete a sensory ballot for each sample to quantify tenderness, juiciness, flavor, overall liking and quality. Each attribute was evaluated on a 100mm line scale. The sensory ballot, volatile and fatty acid data were analyzed by ANOVA and multiple means comparison using SAS while the fMRI data were analyzed using FSL’s FEAT software.ResultsThe results indicated all treatments were equal for tenderness and flavor, but the chicken was the least juicy (P < 0.05) and the grain-fed steak was ranked higher for overall liking (P < 0.05) in comparison to chicken. Furthermore, based on an independent component analysis, there was a significant difference in the functional connectivity (P < 0.05) from the resting state scan to all three treatments within the insular, medial prefrontal cortex, and amygdala regions. Additionally, there were significant differences in connectivity (P < 0.05) between the insula and orbitofrontal cortex in grass-fed compared to grain-fed beef. These areas are involved in processing sensory characteristics related to smell and taste and tend to track differences in preferences and stimulus value. Also, the samples were evaluated for volatile compounds with GC–MS and fatty acids using the FAMES method. Chicken and grass-fed beef was found to have a higher concentration (P < 0.05) of dimethyl sulfone in comparison to grain-fed beef, while the grass-fed steaks possessed a higher concentration (P < 0.05) of toluene in comparison to grain-fed steaks, but not differing from chicken. Dimethyl sulfone and toluene have been tied to grass-fed beef and chicken flavor profiles (Tansawat et al., 2013).ConclusionThe results from the functional brain connectivity in the reward pathways and the chemical components of the different treatments indicated a trend for grain-fed beef to be the most different from grass-fed beef and chicken. Moreover, tying brain activity to the flavor and chemical components in meat can be vital in understanding consumer’s preferences not observed in behavior alone. Therefore, these results can provide a basis to determine the ability to track reactions within the functional connectivity in the brain and the chemical aspects of different steaks to determine and understand consumer’s preferences and the true value of beef and chicken.

Effects of Dry Heat Cookery Method and Quality Grade on the Palatability of Beef Strip Loin Steaks

ObjectivesCooking meat using a clamshell grill has become common in university research settings due to speed, relative low cost, and acceptable repeatability. However, other cooking methods such as charbroiling and salamander grills have also become a popular method in the hotel and restaurant industry. The objective of this experiment was to evaluate the effect of different dry heat cooking methods on beef palatability across a range of USDA quality grades.Materials and MethodsA consumer panel (n = 288) was conducted at Texas Tech University. Strip loin steaks from four different USDA quality grades (Prime, upper 2/3 Choice, lower 1/3 Choice, and Select) were cooked using one of four cooking methods: electric clamshell grill (CLAM), flat top gas grill (FLAT), Charbroiler gas grill (CHAR), or Salamander gas broiler (SAL). After cooking to medium degree of doneness (70–72°C), steaks were cut into cubes (1.3-cm × 1.3-cm × steak thickness), and two cubes were served immediately to 6 predetermined consumers from each steak. Each consumer evaluated 8 samples, representing half of the 16 possible quality grades × cooking method treatment combinations. Consumers scored juiciness, tenderness, flavor liking, and overall liking using electronic ballots with the zero-point anchors labeled as extremely dry, extremely tough, dislike flavor extremely, and dislike overall extremely and the 100-point anchors labeled as extremely juicy, extremely tender, like flavor extremely, and like overall extremely. Also, consumers rated each sample as either acceptable or unacceptable for each palatability trait.ResultsThere were no interactions between the cooking method and quality grade for any of the palatability traits (P > 0.05). Steaks cooked on CHAR had greater (P < 0.05) flavor and overall liking scores, as well as a greater percentage of samples (P < 0.05) that were considered acceptable overall compared to the other cooking methods. Steaks cooked on FLAT were scored lower (P < 0.05) for tenderness and juiciness compared with all other cooking methods. Steaks cooked on CLAM, SAL, and CHAR were scored similarly for tenderness and juiciness (P > 0.05). Steaks cooked on FLAT were scored lower (P > 0.05) than CHAR and SAL for overall liking. Steaks cooked on CLAM had lower (P < 0.05) flavor liking scores than CHAR and SAL. Prime samples had greater scores (P < 0.05) than Low Choice and Select, which were similar (P > 0.05), for tenderness, juiciness, flavor liking, and overall liking, but Prime did not differ from Top Choice (P > 0.05) for any palatability traits.ConclusionThese results indicate cooking method had a significant impact on consumer palatability ratings, and those results were consistent across a range of quality grades. Even though these cooking methods are all classified as dry heat cookery methods, consumers in this study were able to detect differences in tenderness, juiciness, flavor liking, and overall liking. This may be due to increased cooking times or differing types of heat transfer possessed by the various cooking methods. These data suggest cooking steaks by CHAR resulted in the most desirable eating experience, and cooking steaks on FLAT and CLAM were less desirable. However, the low eating satisfaction of FLAT can be linked to low tenderness and juiciness, whereas CLAM liked less due to low flavor liking.

Investigation 0f Beef Brisket Palatability from Three USDA Quality Grades

ObjectivesBarbecuing and smoked meat continues to grow in popularity for food service and consumers at home. However, little research has examined the eating quality differences of point (pectoralis superficialis) and flat (pectoralis profundi) muscles across USDA quality grade. The objective of this study was to investigate differences in smoked beef brisket palatability from three USDA quality grades.Materials and MethodsBeef briskets from the USDA Prime, Average Choice, and Select quality grades (n = 54; 18 per treatment) were collected at a commercial abattoir in Omaha, NE. Briskets were trimmed to 6 mm of external fat, seasoned with a blend of 1:1 coarse kosher salt/coarse black pepper by hand (0.05% of the brisket raw weight), and were held at 2–4° for 12 h prior to cooking. Briskets were cooked in an electric pellet smoker utilizing Gold Blend Hardwood Pellets (red oak, hickory, and maple wood) for ∼4 h to an internal temperature of 63°C; wrapped in aluminum foil, placed back in the smoker for ∼4 h, and cooked to 93°C, then held in an insulated cooler until slicing. Approximately 90 min prior to serving, briskets were separated in point and flat portions, and then sliced (6 mm × 50 mm x cooked depth) perpendicular to the muscle fiber for consumer evaluation and held in warmers at (∼50°C) until serving. Each consumer (n = 360) received six test samples representing all quality grade × muscle combinations to evaluate tenderness, juiciness, flavor liking, overall liking, as well as the acceptability of these traits. Additionally, willingness to pay (WTP) was collected on an individual sample basis.ResultsAn interaction between quality grade and muscle was observed (P ≤ 0.03) for all palatability traits, proportion of acceptable samples, and WTP. Consumers could not distinguish between quality grades of the point portions for tenderness, juiciness, flavor and overall liking (P > 0.05). Point samples, regardless of quality grade were scored greater than Prime flat samples, which were intermediate (P < 0.05). Consumers similarly (P > 0.05) scored Choice and Select flat samples lower for all palatability traits compared to all other treatment combinations. In alignment with palatability traits, consumers were willing to pay the most for point portions, regardless of quality grade (P < 0.05). Consumers WTP of the Prime flat portion was intermediate, and consumers were willing to pay the least for Choice and Select flat portions (P < 0.05).Consumer acceptability followed similar trends as palatability scores. However, a greater proportion of consumers classified Choice and Select point samples as acceptable than that of Prime point samples in all categories of acceptability (P < 0.05). Consumers struggled to distinguish differences in acceptability for Choice and Select flat portions (P > 0.05) in all factors except juiciness acceptability.ConclusionQuality grade had no effect on the eating quality of the point portions of smoked briskets, and point portions received superior palatability scores to flat portions. Briskets from the Prime flat portions had greater eating quality than Choice and Select briskets from the flat portion, and consumers were willing to pay more for what they perceived as superior eating quality. This data suggests that unless consumers prefer the flat portion of the brisket there is no benefit to paying the premium for a prime brisket from a palatability standpoint.

Comparison of Fatty Acid Content between New Zealand Grass-Fed and American Grain-Fed Beef Strip Loins Varying in Marbling Level

ObjectivesMarbling impacts eating quality and consumer preference of beef as it intensifies flavor, and improves tenderness and juiciness. Triglycerides are the predominate lipid in beef and are considered neutral fatty acids, whereas polar fatty acids are found in the phospholipid portion of beef. Diet of cattle during the finishing period can impact type and saturation of fatty acids in meat.The objective of this research was to evaluate differences in neutral and polar lipid fatty acid content from grass-fed and grain-fed beef of varying quality grades sourced from New Zealand and the United States, respectively.Materials and MethodsBeef strip loins (n = 200) representing two fed cattle types (n = 100/finishing type: grass-finished and grain-finished) and five different USDA quality grades (n = 20 per quality grade: USDA Standard, Select, Low Choice, “Top” Choice: High and Average Choice, and Prime) were acquired from beef processing facilities in New Zealand (grass-fed) and Nebraska (grain-fed). A face steak was cut from the anterior end of each strip loin for fatty acid analysis. Face steaks (n = 200) were frozen and stored at the Gordon W. Davis Meat Science Laboratory until further fabrication. Samples were thawed for 12 to 24 h, trimmed of subcutaneous fat and connective tissue and ground. The ground sample was frozen in liquid nitrogen and homogenized for fatty acid analysis. Lipids were extracted, fractionated into neutral lipid (NL) and polar lipid (PL), derivatized to fatty acid methyl esters and determined by gas chromatography.Statistical analyses were conducted using the procedures of SAS (Version 9.3; SAS Inst. Inc., Cary, NC). Treatment comparisons were tested for significance using PROC GLIMMIX with α = 0.05.ResultsInteractions of cattle diet × marbling level affected the overall concentrations (mg/g) of NL saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) (P < 0.05). Saturated fatty acid and MUFA NL concentration decreased as marbling level decreased, as grain-fed Prime was higher (P < 0.05) than all other treatments. Grain-finished and grass-finished Standard had the lowest (P < 0.05) SFA and MUFA NL concentration compared to all other treatments. Concentration of PUFA NL was higher (P < 0.05) for grain-finished Prime than grain-finished Top Choice and grass-finished Prime. No difference was found between grain-finished Low Choice and Select and grass-finished Top Choice NL concentration (P > 0.05), however all were higher (P < 0.05) than grass-finished and grain-finished Standard and grass-finished Select. A cattle diet × marbling level interaction affected the overall PL concentrations of SFA and MUFA (P < 0.05), but not PUFA (P > 0.05). Generally, polar fatty acid content increased as marbling increased for SFA and MUFA. Grain-finished PUFA PL concentration was higher (P < 0.05) than grass-finished samples. Additionally, PUFA PL concentration increased as quality grade decreased (P < 0.05).ConclusionIn conclusion, polar and neutral fatty acid content increased with increasing quality grades except for PL polyunsaturated fatty acids. Additionally, grain-finished beef steaks generally contained a higher SFA and MUFA NL concentration than grass-finished beef steaks for all quality grades except Low Choice and Top Choice.

Influence of maternal protein restriction in primiparous heifers during mid- and/or late-gestation on meat quality and fatty acid profile of progeny

The objective of this study was to evaluate the influence of metabolizable protein (MP) restriction in mid- and/or late-gestation on meat quality characteristics of progeny. Heifers were assigned to 2 levels of dietary protein (control [CON], 102% of MP requirements; or restricted [RES], 80% of MP requirements) at 2 stages of gestation (mid-gestation [MID] and late-gestation [LATE]) in a Balaam's Design crossover treatment structure resulting in 4 treatment combinations (CON-CON, CON-RES, RES-CON, RES-RES). A carryover effect of MID MP treatment on LATE CON indicated CON-CON steaks were more tender (P < .001) than RES CON. Mid-gestation restriction resulted in progeny with increased (P < .05) carcass water, soft tissue moisture, and decreased soft tissue fat percentage compared with progeny from dams receiving MID CON. Reduced maternal MP also differentially influenced the fatty acid profiles of progeny. Results suggest it is possible for progeny to overcome a moderate gestational MP restriction with minimal impacts on carcass composition or meat characteristics.

The Effect of Finishing Diet on Consumer Perception of Enhanced and Non-Enhanced Honduran Beef

The effects of experimental finishing diets and enhancement were tested to determine if they could improve Honduran beef palatability. Fifteen enhanced (ENH) and non-enhanced (NE) paired loins from 7 different finishing diets (n = 210 loins) were fed to Honduran consumers (n = 288). Diets consisted of a grass-finished control (CON) or diets with the inclusion of distiller’s dry grain (DDG), palm kernel meal (PKM), PKM replication (PKMR), sorghum (SORG), soybean meal and corn (SBMC), or sugarcane (SC). An interaction (P < 0.01) occurred between diet and enhancement to influence scores for all palatability traits, willingness to pay (WTP), and acceptability of traits. Consumers found enhanced samples were more tender (P < 0.05) than NE counterparts, excluding ENH- and NE-CON (P > 0.05). Without enhancement, CON was rated more tender (P < 0.05) than all other treatments, except PKMR. All ENH samples were juicier (P < 0.05) and had a flavor that was liked more (P < 0.05) than NE counterparts. Diet alone resulted in similar (P > 0.05) juiciness scores between CON, DDG, PKM, and PKMR; however, CON was rated juicier (P < 0.05) than all other treatments. Among NE samples, flavor liking scores were not different (P > 0.05) between CON, DDG, PKM, PKMR, and SBMC, and CON was liked more (P < 0.05) than SORG and SC. All enhanced steaks, except CON, had greater overall liking scores and WTP values (P < 0.05) than NE counterparts. Diet alone resulted in similar (P > 0.05) overall liking and WTP values between CON, DDG, PKM, PKMR, and SBMC, while SORG and SC were liked less overall (P < 0.05) than CON, which reduced (P < 0.05) WTP values. Experimental diets in conjunction with enhancement were able to improve the consumers’ perception of palatability traits, acceptability, and WTP.

Evaluation of the contribution of tenderness, juiciness, and flavor to the overall consumer beef eating experience

The objectives of this study were to evaluate the contribution of tenderness, juiciness, and flavor to the overall consumer beef eating experience and to evaluate the risk of overall palatability failure due to the unacceptable level of one or more of these traits. Data from 11 previously conducted studies representing a wide range of treatments and levels of eating quality that included more than 1,500 beef samples and 1,800 consumers were compiled and analyzed for this study. Results of a multivariate regression indicated that tenderness, flavor, and juiciness accounted for 43.4%, 49.4%, and 7.4%, respectively, of overall palatability (P < 0.05; R² > 0.99). Additionally, the odds of a steak being rated unacceptable overall when tenderness, juiciness, or flavor were rated unacceptable were 2.2 to 1 (69%), 1.9 to 1 (66%), and 3.3 to 1 (77%), respectively. This indicated overall palatability was 7.2, 6.5, and 12.3 times more likely to be rated unacceptable if tenderness, juiciness, or flavor, respectively, was also rated unacceptable. Additionally, the percentage of samples rated acceptable for each palatability trait increased (P < 0.05) as quality grade increased. More than 88% of USDA Prime samples were rated acceptable for each palatability trait, whereas only 74.8–77.3% of USDA Select samples were rated acceptable for each palatability trait. Marbling score accounted for 14–16% of the variation (P < 0.01) in consumer palatability scores for each trait and intramuscular fat percentage accounted for 17–21% of the variation in each trait (P < 0.01). Logistic equation models for the predicted probability of an acceptable rating for each palatability trait based on intramuscular fat percentage accounted for only a minimal amount of variation (P < 0.01; R² ≤ 0.09). Results of this study indicate the relative contribution of tenderness, juiciness, and flavor to overall beef palatability. They provide evidence that the failure of even a single palatability trait dramatically increases the likelihood of overall palatability failure, indicating that no single palatability trait is most important, as beef palatability is dependent upon the acceptance of all three traits: tenderness, juiciness, and flavor.

Zilpaterol Hydrochloride affects Cellular Muscle Metabolism and Lipid Components of 10 Different Muscles in Feedlot Heifers

This study determined if zilpaterol hydrochloride (ZH) altered muscle metabolism and lipid components of 10 muscles. Crossbred heifers were either supplemented with ZH (n = 9) or not (Control; n = 10). Muscle tissue was collected (adductor femoris, biceps femoris, gluteus medius, infraspinatus, latissimus dorsi, longissimus dorsi, pectoralis profundi, semitendinosus, subscapularis, trapezius) immediately following carcass splitting. The mRNA abundance of AMPkɑ, IGF-I, MHC-I, IIA and IIX, β1-adrenergic receptor (βAR) and β2AR was determined, as well as, cross-sectional area and proportion of myosin isoforms, β1AR, β2AR, β3AR, nuclei, and satellite cell density. Furthermore, neutral (NL) and polar lipid (PL) fatty acids (FA) were quantified (mg/g). Zilpaterol hydrochloride decreased MHC-IIA mRNA (P = 0.007). In addition, ZH decreased total nuclei and β1AR and increased MHC-IIX cross-sectional area (P ≤ 0.021). Quantity of NL FA were not affected by ZH (P ≥ 0.173). However, among PL FA the ratio of PUFA:SFA was greater with ZH (P = 0.048). Muscle type impacted mRNA concentration of AMPkɑ, IGF-I, MHC-I, IIA, IIX, and β1AR mRNA concentration (P ≤ 0.037). Furthermore, the fiber type proportion, fiber cross-sectional area, and the densities of nuclei, β1AR, β2AR, β3AR, and satellite cells were influenced by muscle type (P ≤ 0.030). Total NL FA were affected by muscle (P ≤ 0.046). Meanwhile, total PL FA did not differ due to muscle (P = 0.242). However, prominent PL FA,18:0, 18:1 trans, and 18:2 n-6 were each greater (P < 0.05) among the oxidative subscapularis compared with glycolytic semitendinosus and adductor femoris. Overall, these data reveal that ZH impacts muscle metabolism and myogenic activity that establishes protein deposition. Meanwhile, ZH did not alter triglyceride content (NL), but cell membrane saturation (PL) was influenced, in accordance with alterations to muscle fiber type. Muscle also influenced muscle fiber type and lipid components. Therefore, muscle biology is greatly influenced by muscle but also through dietary inclusion of ZH.

Consumer sensory evaluation and chemical composition of beef gluteus medius and triceps brachii steaks from cattle finished on forage or concentrate diets

The objective of this study was to assess the impact of cattle finishing diet and muscle type on meat quality. Consumer sensory response, proximate composition, Warner-Bratzler shear force (WBSF), fatty acid composition, and volatile compounds were assessed from the gluteus medius (GM) and triceps brachii (TB) muscles of cattle ( = 6 per diet) which were grain-finished (USUGrain) on conventional feedlot or 2 forage diets, a perennial legume, birdsfoot trefoil-finished (USUBFT; ), and grass-finished (USUGrass; ). Diet had an interacting effect with muscle for all sensory attributes ( ≤ 0.002), except aroma and flavor ( ≥ 0.078). In forage-finished beef, tenderness, fattiness, overall liking, and WBSF tenderness of GM was greater ( < 0.05) than TB, whereas for USUGrain, the tenderness, fattiness, overall liking, and WBSF tenderness of both muscles were similar ( > 0.05) but the juiciness of TB was more liked than USUGrain GM ( < 0.05). The juiciness of forage-finished beef did not differ ( > 0.05) between GM and TB. Lower ( < 0.05) intramuscular fat (IMF) percent was determined for USUGrass beef in comparison with USUGrain beef. The IMF percent of USUBFT beef was similar ( > 0.05) to both USUGrass and USUGrain beef. However, IMF percent was not impacted by muscle type ( = 0.092). The ratio of -6:-3 fatty acids was affected by muscle dependent on diet ( = 0.016). The ratio of -6:-3 fatty acids was affected by the interaction of muscle × diet ( = 0.016). Between forage diets (USUGrass and USUBFT), -6:-3 ratios were similar ( > 0.05) between GM and TB, whereas within USUGrain, the GM was greater ( < 0.05) than the TB. Cumulative MUFA was greater ( < 0.05) in USUGrain compared with both USUGrass and USUBFT, which were similar ( > 0.05). Strecker aldehydes, ketones, pyrazines, and methional were affected ( ≤ 0.036) by muscle and found to have a greater concentration in GM compared with TB. Overall, consumers determined that USUGrain GM and TB had similar ( > 0.05) quality ratings. However, within forage-finished beef, the GM was perceived more frequently ( < 0.05) to be of premium quality and the forage-finished TB was more frequently ( < 0.05) rated as having unsatisfactory quality. These findings were in agreement with ratings of tenderness and overall liking. Therefore, in the context of our consumer group grilled GM and TB steaks, grain-finished beef provided more uniform quality and eating experience compared with forage-finished beef.