Beef Strip Loins Research Articles

Palatability and Biochemical Factors of Beef from Mature Cattle Finished on a Concentrate Diet Prior to Harvest

The objective of this study was to investigate the influence of grain-finishing on mature beef palatability. Beef strip loins (n = 15 per treatment) from 2 marbling score groups [Slight (SL) and Traces/Practically Devoid (TR/PD)] and 3 carcass types [young fed (YF), mature fed (MF), and mature unfed (MU)] were collected. Young fed and MF cattle were grain-finished prior to harvest, whereas, beef from MU cattle were not identified as being grain-finished prior to harvest. Consumer and trained sensory panels evaluated steaks for palatability characteristics. Additionally, Warner-Bratzler shear force (WBSF), collagen solubility, sarcomere length, and volatile compounds were evaluated. Consumer ratings were not influenced (P > 0.05) by an interaction of main effects. Slight samples were greater (P < 0.05) than TR/PD samples for tenderness, juiciness, flavor, and overall like. Trained panelists rated SL samples more tender (P < 0.01) than TR/PD samples. Additionally, YF and MU steaks were the most and least tender (P < 0.01), respectively. No differences (P > 0.05) were observed among SL samples for beef flavor, beef flavor intensity, or off-flavor intensity due to carcass type. However, TR/PD-MF and MU steaks had more intense (P < 0.01) off-flavors. Steaks from YF and MF carcasses had lower (P < 0.01) WBSF values than steaks from MU carcasses. Percentage of heat soluble collagen was greatest (P < 0.01) in YF carcasses. Among SL treatments, sarcomere length was not affected (P > 0.05) by carcass type; however, MF and MU carcasses with TR/PD marbling scores had shorter (P < 0.05) sarcomeres than YF carcasses. Various volatile compounds were influenced (P < 0.05) by treatment and showed relationships with sensory ratings. Improvements in palatability were observed due to grain-finishing mature cattle, suggesting an adequate degree of marbling could offset negative palatability traits typically associated with beef from mature cattle.

Marbling Texture’s Effects on Beef Palatability

The objective of this study was to evaluate the effects of marbling texture on consumer and trained sensory panel ratings of beef strip loin steaks from 3 USDA quality grades. Beef strip loins (n = 117) were selected from 3 quality grades [Top Choice (Modest00 – Moderate100 marbling), Low Choice (Small00 – Small100 marbling), and Select (Slight00 – Slight100 marbling)] to equally represent three different marbling texture groups: fine, medium, and coarse, via visual appraisal. There were no quality grade × texture interactions (P > 0.05) for all of the traits evaluated. Consumers (n = 104) rated all marbling texture groups similar (P > 0.05) for tenderness, juiciness, flavor, and overall liking, as well as rated a similar (P > 0.05) percentage of samples from each marbling texture group acceptable for each palatability trait. Moreover, consumers indicated no preference (P > 0.05) among marbling texture groups for visual desirability or likelihood to purchase. However, trained sensory panelists rated coarse marbled steaks higher (P < 0.05) than fine or medium marbled steaks for both beef flavor intensity and sustained juiciness, as well as higher (P < 0.05) for initial juiciness than medium textured steaks. There were no differences (P > 0.05) among marbling texture groups for Warner-Bratzler shear force, slice shear force, and pressed juice percentage. Low Choice steaks were rated higher (P < 0.05) than Select steaks by consumers for tenderness, flavor liking, and overall liking, but similar (P > 0.05) to Top Choice. Results from this study indicate marbling texture had no impact on consumer evaluations of eating quality and only minimal effects on trained sensory panel palatability ratings and therefore provides no palatability-based evidence for the exclusion of coarse marbled carcasses from current and future branded beef programs.

Marbling Texture Does Not Affect Muscle Fiber Type of Beef Strip Loin Steaks

Marbling Texture Does Not Affect Muscle Fiber Type of Beef Strip Loin Steaks

Consumer Sensory Evaluation of Beef Strip Loin Steaks from 5 Quality Treatments Cooked To 6 Degrees of Doneness

ObjectivesThe objective of this study was to determine the effect of degree of doneness (DOD) on the palatability of beef strip loin steaks of varying marbling levels.Materials and MethodsPaired strip loins (IMPS # 180) were collected from 4 USDA quality grades [Prime, Top Choice (Modest and Moderate marbling), Low Choice, Select; n = 12 pairs/quality grade]. Additionally, 12 pairs of Select strip loins were collected for a salt and alkaline phosphate enhancement solution (108% of raw weight). Subprimals were aged for 21 d and fabricated into 2.54-cm thick steaks. Steaks were fabricated in groups of 3 consecutively cut steaks, with a total of 6 groups per strip loin pair. Groups were assigned to a DOD: very-rare (55°C), rare (60°C), medium-rare (63°C), medium (71°C), well-done (77°C) or very well-done (82°C). Steaks were cooked on clamshell style grills to their specified DOD. Consumers (n = 360) were fed 8 samples under red lighting and evaluated for juiciness, tenderness, flavor, and overall liking on continuous line scales. Additionally, consumers rated each trait as either acceptable or unacceptable.ResultsThere were no interactions (P > 0.05) between quality treatment and DOD for consumer ratings of all palatability traits. Select Enhanced steaks had the highest (P < 0.05) consumer ratings for all traits, followed by Prime steaks having higher (P < 0.05) ratings than Top Choice, Low Choice, and Select steaks. Select steaks had the lowest (P < 0.05) consumer ratings for all traits except tenderness, for which they were similar (P > 0.05) to Low Choice. Juiciness was similar (P > 0.05) between very-rare and rare, as well as between rare and medium-rare. Very-rare, rare, and medium-rare steaks had similar (P > 0.05) ratings for all palatability traits except juiciness. There was a quality grade by DOD interaction (P < 0.05) for the percentage of steaks rated acceptable for juiciness, tenderness, and overall liking. At very rare, rare, and medium-rare, all quality grades except Select were similar (P > 0.05) in the percentage of steaks rated acceptable for juiciness. However, as DOD increased, marbling had a greater impact, with Prime having a greater (P < 0.05) number of samples rated acceptable for juiciness than all non-enhanced samples at very well-done. Select Enhanced steaks had the greatest (P < 0.05) percentage of samples rated acceptable for tenderness at very-rare, but Prime was similar (P > 0.05) to Select Enhanced for all other DOD. Additionally, Select had the lowest (P < 0.05) percentage of steaks rated acceptable for tenderness at medium-rare and medium, but were similar (P > 0.05) to Low Choice at all other DOD. Prime and Select Enhanced steaks had similar (P > 0.05) percentages of samples rated acceptable overall for all DOD except medium and well-done, in which Select Enhanced was higher (P < 0.05). Select had a similar (P > 0.05) percentage of steaks rated acceptable as both Choice treatments at very-rare and rare, but had a lower (P < 0.05) percentage than Low Choice at medium-rare and was lower than both at medium.ConclusionThese results indicate that increased marbling level or enhancement has a positive impact on palatability ratings across all DOD. However, beef with higher marbling levels are acceptable at a higher rate at elevated DOD. With this, consumers can purchase steaks of lower quality when cooking to lower DOD, and vice versa, and still have a desirable eating experience.

Impact of Dry Heat Cookery Method on Consumer Ratings of Beef Strip Loin Steaks Following Sous Vide Preparation

Impact of Dry Heat Cookery Method on Consumer Ratings of Beef Strip Loin Steaks Following Sous Vide Preparation

Identifying the Influence of Post-Mortem Aging Length and Method on Flavor and Tenderness of Beef Strip Loins

ObjectivesAging of beef is one widely-accepted method to enhance palatability characteristics. There has not been a study published aimed specifically at identifying the effect of aging on flavor compound development. Therefore, the objective of this study was to identify compositional changes in flavor and tenderness of beef aged at different lengths and using different methods.Materials and MethodsPairs of strip loins (n = 38) were collected from commodity USDA Choice beef carcasses and fabricated into a total of 8 sections per carcass. Sections were randomly assigned to 1 of 8 aging treatments: 1) 3 d wet-aged; 2) 14 d wet-aged; 3) 28 d wet-aged; 4) 35 d wet-aged; 5) 49 d wet-aged; 6) 63 d wet-aged, 7) 21 d dry-aged; 8) 14 d wet-aged followed by 21 d dry-aged. Upon completion of treatment, sections were fabricated into 3 steaks, each of which was allocated for sensory, shear force, or chemical analysis. Sensory attributes, including beef lexicon flavor notes and tenderness, were quantified by a trained panel using a 15-point scale. Slice shear force (SSF) and Warner-Bratzler (WBSF) shear force was determined for each sample. Uncooked samples were analyzed for volatile organic compounds known to contribute to beef flavor as well as fatty acids. Treatment comparisons made within the same carcass were tested for significance using SAS PROC GLIMMIX (SAS Inst. Inc., Cary, NC) with ɑ < 0.05.ResultsWet-aging longer than 35 d resulted in decreased (P < 0.01) ratings for beef flavor ID, browned, and roasted flavors and increased (P < 0.01) ratings for sour, oxidized, nutty, musty/earthy, and liver-like. However, beef wet-aged up to 28 d showed no change (P ≥ 0.05) in flavor notes. Dry-aging resulted in the greatest ratings for beef flavor ID, browned, and roasted. Additionally, the additive effect of using both wet- and dry-age methods resulted in intensification of the musty/earthy and nutty flavor notes typically associated with dry-aged beef, as well as sour notes. The SSF and WBSF generally decreased as aging time increased. Yet, no significant differences (P ≥ 0.05) in SSF values were found past 35 d of wet-aging, and no significant differences (P ≥ 0.05) in WBSF values were found past 28 d of wet-aging. Volatile flavor compound analysis showed n-aldehydes nonanal, octanal, and hexanal increase up to 35 d of wet-aging and decrease at subsequent aging lengths. Additionally, Strecker aldehydes phenylacetaldehyde, 2-methylbutanal, and 3-methylbutanal all increased after 35 d of wet-aging. Finally, ethanol production increased substantially after 35 d of wet-aging, while acetaldehyde production decreased at the same aging length.ConclusionThese findings show aging as an effective method of improving palatability attributes in beef. Yet, utilizing extreme aging parameters changes the flavor profile of beef, as notes of sour, oxidized, nutty, musty/earthy, and liver-like develop, without a meaningful improvement in tenderness. This change in flavor profile may, in part, be due to volatile changes late in the wet-aging period, where the oxidative breakdown of lipids, generation of aldehydes, and the dehydrogenation of acetaldehyde to ethanol occur. Additionally, dry-aging in combination with wet-aging creates a unique flavor profile. Ultimately, these results provide a baseline for establishments to select an aging protocol best suited for their need in promoting a high-quality eating experience.

Duration of Exposure to a High-Concentrate Diet Prior to Pasture-Finishing Affects Fatty Acid Composition and Volatile Compounds of Beef Strip Loin Steaks

Duration of Exposure to a High-Concentrate Diet Prior to Pasture-Finishing Affects Fatty Acid Composition and Volatile Compounds of Beef Strip Loin Steaks

Understanding the Impact of Oven Temperature and Relative Humidity on the Beef Cooking Process

The objective of this study was to evaluate the roles that cooking rate and relative humidity has on the sensory development of beef strip steaks. Thirty USDA Choice beef strip loins were collected from a commercial packing facility. Each strip loin was cut into steaks and randomly assigned to 1 of 6 cooking methods utilizing 2 oven temperatures (80°C and 204°C) and 3 levels of relative humidity [zero (ZH), mid (MH), and high (HH)]. Cooked steaks were used to evaluate internal and external color, Warner-Bratzler and slice shear force, total collagen content, protein denaturation, and trained sensory ratings. Relative humidity greatly reduced cooking rate, especially at 80°C. Steaks cooked at 80°C-ZH had the greatest (P &lt; 0.01) cook loss of all treatments, and cook loss was not affected (P &gt; 0.05). Steaks cooked at 80°C-ZH appeared the most (P &lt; 0.01) well-done and had the darkest (P &gt; 0.01) surface color. Total collagen was greatest (P &lt; 0.01) in steaks cooked with ZH, regardless of oven temperature. Myosin denaturation was not affected (P &gt; 0.05) by treatment. Increased (P = 0.02) sarcoplasmic protein denaturation was observed with ZH and MH, while increased (P = 0.02) actin denaturation was observed only with ZH. Oven temperature did not influence (P &gt; 0.05) protein denaturation. Trained panelists rated steaks the most tender (P &lt; 0.01) when cooked at 80°C and with ZH and MH. Humidity did not affect (P &gt; 0.05) juiciness at 204°C; however, MH and HH produced a juicier (P &lt; 0.01) steak when cooked at 80°C. Humidity hindered (P &lt; 0.01) the development of beefy/brothy and brown/grilled flavors but increased (P = 0.01) metallic/bloody intensity. Lower oven temperatures and moderate levels of humidity could be utilized to maximize tenderness, while minimally affecting flavor development.

Grilling Temperature Effects on Trained Sensory Panel and Warner Bratzler Shear Force of USDA Select Beef Striploin Steaks

ObjectivesThe objective of this study was to evaluate the trained sensory panel and Warner-Bratzler shear force (WBSF) responses to 5 different grilling temperatures on USDA Select strip steaks.Materials and MethodsThirty USDA Select strip loins were collected from a major packing plant where carcass data was collected, then aged for 14 d. After aging, 10 steaks were cut 2.54 cm thick from each loin, randomized among 1 of 5 treatment grill surface temperatures (149°C, 177°C, 204°C, 232°C, or 260°C), and given a WBSF or trained sensory panel designation. Steaks were individually vacuum-packaged and placed in frozen storage until analyses were performed. Individual steaks were thawed in refrigerated storage (4°C) for 12 to 24 h prior to cooking. Steaks were cooked on a commercial flat top grill, preheated to the designated grill surface temperature treatment. All steaks were cooked to an internal end point temperature of 71°C, turning once at 35°C. Six, 1.3 cm diameter core samples were collected from each WBSF steak after being refrigerated (4°C) overnight. Steaks designated for trained panel were cut into 1.3cm cubes and served, warm, to an expert trained beef flavor descriptive panel. Each steak was evaluated on a 16-point intensity scale for 18 flavor attributes, tenderness, and juiciness. Data were analyzed using the GLM procedure in SAS with significance set at an ɑ value < 0.05, where grilling temperature served as the main effect and loin, panelists, day, and serving order served as covariates. The LSMeans procedure in SAS (SAS Inst. Inc., Cary, NC) was used to separate significant means (P < 0.05).ResultsWarner-Bratzler shear force values were not affected (P > 0.05) by grill temperature and were generally low (mean WBSF = 3.1779 kg). At lower grill temperatures, beef identity, brown, roasted, burnt, and bitter were lower (P < 0.05) and bloody/serumy, sour, and juiciness were higher (P < 0.05). As grill temperatures increased, bloody/serumy, sour, and juiciness were lower (P < 0.05) and beef identity, brown, roasted, burnt, and bitter were higher (P < 0.05).ConclusionGrill surface temperature can be used to change beef flavor trained sensory panel scores, but has no impact on tenderness.

The effect of carbon monoxide pretreatment exposure time on the colour stability and quality attributes of vacuum packaged beef steaks

The effect of 5% CO pretreatments prior to vacuum packaging of beef striploin steaks (Longissimus thoracis et lumborum, LTL) on quality attributes, primarily colour stability was investigated. The aim was to determine the optimum pretreatment that would induce the desirable red colour, while allowing discoloration to occur by the end of a 28-day display period (2°C), so as to not mask spoilage. A range of pretreatment exposure times (1, 3, 5, 7, 9, 15 and 24h) were applied to steaks using a gas mixture of 5% CO, 60% CO2 and 35% N2. The 5h CO pretreatment exposure time achieved the desirable colour and discoloration reached unacceptable levels (a*=12, C*=16) by the use-by date (28days), thus ensuring consumers' of a reliable visual indication of freshness and addressing concerns about safety. The 5% CO pretreatment had no negative effect on microbiological safety, lipid oxidation, cooking loss and WBSF measurements at the end of storage (P>0.05).

Comparison of Two Volatile Sampling Techniques Based on Different Loading Factors in Determination of Volatile Organic Compounds Released from Spoiled Raw Beef

Evaluation of meat volatiles is an increasing concern due to the development studies for spoilage sensors in order to inform consumers if meat spoiled or not. Since the reliable measuring of volatiles in headspace is important for designing a sensor, preconcentration techniques for meat matrix should be investigated. This study describes the effect of three sample amounts: total volume ratio (loading factors) with 0.025, 0.05, and 0.10 kg/L applied in two preconcentration sampling techniques: solid phase microextraction (SPME) and gas flushing on Tenax with thermal desorption to explain the interactions and relationship between sample amount and extracted analytes for spoiled beef striploin. The ratio of the sample amount of beef meat in the chamber and the total volume of chamber is called as “loading factor”. The results showed that the volatile profiles did not vary significantly, but the levels were affected with the extraction technique and loading factor. The volatile organic compounds identified in the early stages of meat spoilage include alcohols, aldehydes, ketones, esters, and amine compounds. While amines were measured only with Tenax, ethyl acetate was detected only with SPME. The total peak area of volatiles with Tenax (~390 × 10−6 AU at 0.05 kg/L) were higher than SPME sampling (~290 × 10−6 AU at 0.05 kg/L) in each loading factor. Although optimum loading factor depended on the type of volatile, 0.05 kg/L loading factor resulted the most efficient extraction by the two preconcentration techniques for most of the volatiles generally.

Relationship between Heifer Carcass Maturity and Beef Palatability

ObjectivesOur objective was to determine the relationship between carcass maturity and beef palatability of strip loin and outside round steaks.Materials and MethodsLeft sides of A (n = 30), B (n = 30), and C (n = 30) maturity heifer carcasses under 30 mo of age by dentition were used. Average skeletal maturities of the groups were A67, B49, and C48. Carcasses were selected to ensure similar marbling scores across maturity groups, and average marbling scores were Sm94, Mt02, and Mt01 for A, B, and C maturity carcasses, respectively. Beef strip loins (IMPS 180) and outside (bottom) rounds (IMPS 171B) obtained from these carcasses were purchased from AB Foods (Toppenish, WA) and transported to the University of Idaho Meat Science Laboratory. Following a 14-d aging period, wholesale cuts were removed from vacuum packaging and ischiatic heads were removed from outside rounds to produce trimmed flats. Two 2.54 cm-thick steaks were cut from the trimmed flats and anterior ends of strip loins. Steaks were used to measure Warner-Bratzler shear force (WBSF), cook loss, insoluble and total collagen, and consumer sensory attributes. Steaks used for WBSF were weighed, cooked on open hearth broilers to an internal temperature of 40°C, then turned and cooked to a final internal temperature of 71°C. Cooked steaks were re-weighed to determine cook loss and cooled to 4°C. Six cores (1.27-cm diameter) were then removed from each steak parallel with the muscle fibers and then sheared perpendicular to muscle fiber orientation using a Warner-Bratzler shear machine (GR Manufacturing, Manhattan, KS). Samples from cooked steaks were frozen at –20°C and used to determine insoluble and total collagen. Sensory panel steaks were frozen at –20°C after aging, and allowed to thaw at 4°C for 24 h prior to the consumer panel. Steaks were cooked as previously described and four 1.27-cm × 1.27-cm × steak thickness cubes were obtained from each steak. Separate sensory panels were conducted for strip loin and outside round steaks. Consumers (n = 72 panelists per panel) evaluated cooked samples for overall acceptability, tenderness, juiciness, and flavor using a 9-point scale (9 = like extremely, 1 = dislike extremely). Using an incomplete block design, panelists evaluated 5 samples from the 3 maturity groups. Data were analyzed using the Mixed Model procedure of the Statistical Analysis System (SAS Inst. Inc., Cary, NC). Significance was determined at P < 0.05 and data were considered trending at P < 0.10.ResultsHeifer carcass maturity did not significantly affect WBSF or cook loss for either outside round or strip loin steaks (P > 0.23). Likewise, insoluble and total collagen were not different for either steak type from A, B, or C maturity carcasses (P > 0.89). Strip loin steaks from C maturity carcasses tended to have higher overall acceptability (P = 0.08) and juiciness (P = 0.09) than steaks from B maturity carcasses, but steaks from B and C maturity carcasses did not differ from strip loin steaks obtained from A maturity carcasses (P > 0.11.). No differences in tenderness or flavor were observed due to maturity (P > 0.24). Similarly, maturity had no effect on sensory characteristics of outside round steaks (P > 0.30).ConclusionIn conclusion, advanced skeletal maturity does not decrease palatability of carcasses from cattle under 30 mo of age.

The Effects of Novel Antimicrobials on Quality and Shelf-Life Characteristics of Blade Tenderized Beef Strip Loins

ObjectivesBeef tenderness is an important palatability attribute relating to consumer satisfaction. To enhance tenderness, and consumer satisfaction, blade tenderization (BT) is commonly employed; however, foodborne outbreaks have been associated with BT products. Application of antimicrobial interventions prior to BT is commonly employed by the meat industry to reduce the inherent risk of BT. As new antimicrobial technologies arise, they must also be tested to ensure quality and shelf life is not compromised. The objectives of this study were to investigate the effects of pulse ultra-violet light (PUV), 5% levulinic acid + 0.5% sodium dodecyl sulfate (LVA+SDS), and electrolyzed oxidizing water (EOW; 50 ppm Cl), on beef strip loin (SL) subprimals prior to BT, and assess their effects on shelf life and sensory characteristics compared to SL treated with 4.5% lactic acid (LA), and no antimicrobial intervention (CON).Materials and MethodsWhole USDA Choice beef SL (n = 75) of known date were assigned randomly to antimicrobial interventions across 3 replicates. Pulse UV samples were treated for 15 s at 5.754 J/cm2 6 ± 2 cm from the quartz window. All other treatments were applied to subprimals using a 6-nozzle sanitizing cabinet (0.42 L/nozzle·min–1 at 275.79 kPa). After treatment, all SL made a single pass, lean side up, through a mechanical tenderizer (Ross TC700MC). After BT, SL were vacuum packaged, boxed, and stored (0 ± 1°C) for 7 d. Following storage, subprimals were squared and 2 steaks (2.54 cm) were cut from the anterior face with 1 designated for Warner-Bratzler shear force and the other for trained sensory analysis. Pulse UV samples were not included in sensory analysis due to the PUV equipment being previously utilized in pathogen studies. After steak removal, roasts (5 cm) were cut for shelf life analysis, packaged in Styrofoam trays with PVC overwrap and randomly assigned to 0, 1, 2, 3, 5, or 7 d of display in open top coffin display cases (0 ± 1.5°C, 2 defrost cycle every 24 h) and 24 h lighting (1600- 2100 lux; 30000K). On each day objective color was measured on d 7 roasts for L*, a*, b*, hue, chroma, and ∆E. Aerobic plate count (APC) and thiobarbituric acid reactive substance analysis (TBARS) were also quantified on d 0, 1, 2, 3, 5, and 7 roasts. Data were analyzed using Proc Mixed (V9.4, SAS Inst. Inc., Cary, NC) as a randomized split-plot where subprimal was the whole plot and steak or roast was the subplot. The PDIFF option of least squares means was utilized to test for differences (ɑ ≤ 0.05).ResultsAntimicrobial treatment prior to BT did not (P > 0.05) affect objective color measures. However, as display progressed L*, a*, b*, and chroma decreased (P < 0.05), while hue and ∆E values increased (P < 0.05). As expected, APC increased (P < 0.05) with extended display, and, even though APC were similar (P > 0.05) among CON (5.64 log CFU/cm2), PUV (5.20 log CFU/cm2), and EOW (5.78 log CFU/cm2), both LVA+SDS- and LA-treated roast had lower (P < 0.05) APC than all other treatments (3.49 and 4.33 log CFU/cm2, respectively). However, antimicrobial treatments did not (P > 0.05) affect lipid oxidation, WBSF, or sensory characteristics.ConclusionThe results from this study suggest that LVA+SDS could be used as an antimicrobial prior to SL BT without compromising quality or sensory characteristics.

Optimization and Commercial Implementation of Freeze/Age Process to Improve Beef Tenderness

ObjectivesThe effects of freezing/thawing/aging beef steaks can enhance tenderness over postmortem aging alone. The objective of this study was to evaluate the effects of freezing/thawing and various days of postmortem (DPM) aging on beef strip loins and evaluate if this practice could be implemented in a commercial setting to improve tenderness.Materials and MethodsUSDA Select carcasses (n = 60) derived from cattle of Angus phenotype (USDA, 1996) that were not predicted tender by VBG2000LED beef carcass grading camera were selected from a commercial beef packing plant. Paired strip loins were collected from each carcass, vacuum packaged and randomly assigned to one of two treatments, Frozen/Thawed/Aged (FRAGE) or a fresh never-frozen control. FRAGE treatment strip loins were frozen at 2 DPM using a blast freezer at –39 to –40°C for 2 h. After freezing strip loins were thawed the following day in water at 4 to 5°C for 2 h then placed on aging racks a 5°C to finish thawing. Carcasses (i.e., paired strip loins) were assigned randomly to either 9, 16, or 23 DPM. Purge loss was determined for each strip loin prior to cutting. After strip loins were aged for the appropriate time, strip loins where cut into 2.5 cm steaks and assigned to various evaluations based on position, including SSF (position 1 to 3), simulated retail display color stability evaluation (position 4), and simulated retail display purge loss evaluation (positions 5–8). The 4 steaks for purge loss evaluation were assigned to display day (1, 4, 7, or 11 d) using a randomized block. Data were analyzed using the GLIMMIX procedures of SAS (Version 9.3; SAS Inst. Inc., Cary, NC) as a split-split plot design. Postmortem aging (DPM) was the whole plot with treatment (freezing) as the sub plot, display day (when applicable) as the sub-sub plot and their interactions were considered fixed effects. Carcass was considered a random effect.ResultsSteaks from FRAGE strip loins were more tender (P < 0.01) than steaks from the control group regardless of postmortem aging (13.1 vs. 15.4 kg). Postmortem aging also influenced SSF values (P < 0.01) regardless of freezing treatment. SSF values were similar for strip loins aged 16 DPM (13.1 kg) and 23 DPM (13.7 kg); however, both DPM had lower SSF values (P < 0.01) when compared to strip loins aged 9 DPM (15.9 kg). The two-way interaction between treatment and aging was observed (P < 0.01) for strip loin purge loss. The least amount of purge loss came from control strip loins regardless of aging time (0.79 vs. 2.52%), FRAGE strip loins aged 9 DPM were intermediate, while FRAGE strip loins aged 16 or 23 DPM had the greatest amount of purge loss (P < 0.01). Three different two-way interactions were observed (P < 0.01) when evaluating steak purge loss (DPM × Treatment, DPM × Display Day, and Treatment × Display Day). The three-way interactions were not significant (P = 0.79). FRAGE steaks produced a greater amount (P < 0.01) of purge loss when compared to fresh steaks regardless of display day or aging time (3.50 vs. 1.96%).ConclusionThe FRAGE process improves tenderness of beef subprimals but also increases the amount of purge from these cuts. Further research is needed to find a way to limit the water loss while still capitalizing on the tenderness benefits. This project was funded, in part, by The Beef Checkoff.

Evaluation of the Reduction of Salmonella Surrogate in Beef Strip Loins at Temperatures Lower Than 54.4°C

ObjectivesAccording to the CDC, Salmonella is a leading cause of gastroenteritis in humans and continues to be significant in relation to public health concerns for the food industry. This may be attributed to inadequate heating/cooking. According to Appendix A to achieve a 6.5-log10 reduction in Salmonella the lowest time/temperature that can be utlized is 54.4°C for 112 min. To date there is limited research in utilizing lower temperatures for strip loins to increase juiciness and perceived tenderness. This study evaluated the reduction of Salmonella surrogate on strip loins cooked to internal temperatures of 54.4°C or lower to determine if temperatures less than 54.4°C would achieve a 6.5-log10 reduction in accordance with Appendix A.Materials and MethodsA local company provided their proprietary brine and rub ingredients and raw meat materials for the experiment. A cocktail of 5 stains of Escherichia coli (ATCC BAA-1427, 1428, 1429, 1430, 1431) were utilized. These strains are approved by the USDA as surrogates for Salmonella for in plant verification studies. Inoculations were prepared by inoculating TSB with each E. coli strain and allowed to grow at 37°C for approximately 24 h. Strip loins were dip inoculated with E. coli to achieve a 7.5-log10 CFU/g inoculation level on the meat. Strip loins were pumped 15% with a brine solution and then rubbed with the rub. They were then placed into cook-in bags and vacuum-sealed. Packages were placed on a smokehouse trolley in the smokehouse. The combination of temperatures and times held were 54.4°C for 2 and 3 h, 51.7°C for 3 and 5 h, and 48.9°C for 10 and 12 h. Times were determined utilizing a model from the North American Meat Institute. Internal temperatures were continuously monitored utilizing Type-K Thermocouples. Once removed from the smokehouse 1-kg samples were taken from each strip loin and were vacuum-packaged for Salmonella surrogate enumeration. Samples were taken to Food Safety Net Services for enumeration. MacConkey Sorbital Agar was utilized to determine Salmonella surrogate survival. The experiment consisted of 3 replications with 2 samples per treatment per replication. Data were analyzed using excel to determine variance and the GLM procedure of SAS (SAS Inst. Inc., Cary, NC) to obtain lsmeans with statistical differences set at p < 0.05.ResultsNo treatment was more effective at inactivating the Salmonella surrogate than another (p > 0.05). However, there was a trend (p = 0.08) that the temperature 54.4°C was more effective at inactivating the Salmonella surrogate than 48.9°C. Strip loins had a 6.2-log10 reduction (var = 0.3) at 54.4°C when held for 2 h and a 6.4-log10 reduction (var = 0.07) when held for 3 h. When held at an internal temperature of 51.7°C a 5.1-log10 reduction (var = 0.59) was achieved when held for 3 h and a 5.5-log10 reduction (var = 0.59) when held for 5 h. Strip loins that were cooked to 48.9°C and held for 10 h resulted in a 4.8-log10 reduction (var = 3.23) and when held for 12 h achieved a 4.9-log10 reduction (var = 1.28). Reduction from brine and rub will be presented on the poster.ConclusionResults suggest that lower temperatures may possibly achieve a 6.5 to 7.0-log10 reduction in accordance with Appendix A if the product was held at the temperature for the correct time. This information is useful for companies that wish to use other temperature/time relationships than those stated in Appendix A.

Relationship between Physiological Maturity and Retail Shelf Life in Heifer Carcasses

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

Marbling Texture Does Not Affect Consumer Preference of Beef Strip Loin Steaks

Marbling Texture Does Not Affect Consumer Preference of Beef Strip Loin Steaks

Effectiveness of a Commercial Lactic Acid Bacteria Intervention Applied to Inhibit Shiga Toxin-Producing Escherichia coli on Refrigerated Vacuum-Aged Beef

Because of their antagonistic activity towards pathogenic and spoilage bacteria, some members of the lactic acid bacteria (LAB) have been evaluated for use as food biopreservatives. The objectives of this study were to assess the antimicrobial utility of a commercial LAB intervention against O157 and non-O157 Shiga-toxigenic E. coli (STEC) on intact beef strip loins during refrigerated vacuum aging and determine intervention efficacy as a function of mode of intervention application. Prerigor strip loins were inoculated with a cocktail (8.9 ± 0.1 log10 CFU/ml) of rifampicin-resistant (100.0 μg/ml; RifR) O157 and non-O157 STEC. Inoculated loins were chilled to ≤4°C and treated with 8.7 ± 0.1 log10 CFU/ml LAB intervention using either a pressurized tank air sprayer (conventional application) or air-assisted electrostatic sprayer (ESS). Surviving STEC were enumerated on tryptic soy agar supplemented with 100.0 μg/ml rifampicin (TSAR) to determine STEC inhibition as a function of intervention application method (conventional, ESS) and refrigerated aging period (14, 28 days). Intervention application reduced STEC by 0.4 log10 CFU/cm2 (p < 0.05), although application method did not impact STEC reductions (p > 0.05). Data indicate that the LAB biopreservative may assist beef safety protection when utilized within a multi-intervention beef harvest, fabrication, and aging process.

Repeatability and Accuracy of the Pressed Juice Percentage Method at Sorting Steaks into Juiciness Categories

The objective of this study was to evaluate the repeatability of the Pressed Juice Percentage (PJP) as well as to determine the accuracy of previously determined PJP thresholds at sorting beef strip loin steaks into categories based on the probability of being rated juicy by sensory panelists. Beef strip loin steaks representing 3 USDA quality grades (Prime, Low Choice, and Low Select) and Low Select strip loin steaks enhanced to 108% of the raw weight with a water, salt, and alkaline phosphate solution were cooked to three degrees of doneness [DOD; Rare (60°C), Medium (71°C), Very Well-Done (82°C)] to maximize variation in juiciness. Paired steaks were evaluated for PJP, Slice Shear Force (SSF), and Warner-Bratzler shear force (WBSF). Additionally, steaks representing Prime, Low Choice, and Low Select that were non-enhanced or enhanced with the same enhancement solution cooked to three DOD [Rare (60°C), Medium (71°C), Very Well-Done (82°C)] from a previously conducted sensory study were used to evaluate the ability of PJP to sort steaks into juiciness categories. Results indicated PJP had a high repeatability coefficient of 0.70, indicating only a small portion (30%) of the variation observed was due to sample measurement differences between paired samples. The repeatability of SSF and WBSF were 0.68 and 0.85, respectively. The evaluated PJP threshold values accurately segregated strip loin steaks by the probability of a sample being rated as juicy (mean juiciness rating of &gt; 50) by consumers. The actual percentage of juicy samples was determined to be 41.67, 72.31, 89.33, and 98.08% for the predicted &lt; 50%, 50 to 75%, 75 to 90%, and &gt; 90% categories, respectively. Results of this study indicate the PJP juiciness measure is both repeatable and accurate in sorting beef strip loin steaks based on the likelihood of a steak being classified as juicy by consumers.

Consumer Evaluation of Beef Strip Loins of 3 Quality Grades Cooked To Multiple Degrees of Doneness

ObjectivesThe objective of this study was to determine the effect of enhancement on consumer palatability scores of three quality grades of beef strip steaks when cooked to three degrees of doneness.Materials and MethodsStrip loins (n = 72) were selected to equally represent three quality grades: USDA Prime, Low Choice, and Low Select. Within each grade, half were enhanced to 108% of the green weight with a water, salt, and alkaline phosphate solution. All strip loins were aged 21 d and cut into 2.5-cm thick steaks. Each strip loin was sectioned into thirds, with each third assigned to 1 of 3 degrees of doneness (DOD; Rare: 60°C; Medium: 71°C; or Very Well-Done: 82°C). Within each third, paired steaks were assigned to either consumer evaluation or objective measurements of Slice Shear Force (SSF) and Pressed Juice Percentage (PJP). Steak assignment was balanced across all strip loins in each treatment and steaks were individually frozen (–20°C) until subsequent analyses. One steak was evaluated for SSF and PJP, the other was evaluated by consumers (n = 252) for juiciness, tenderness, flavor liking, and overall liking on 100-mm line scales. Consumers were also asked to rate each trait as either acceptable or unacceptable and to categorize samples into 1 of 4 quality levels (unsatisfactory, every day, better than every day and premium).ResultsConsumer panelists rated all enhanced treatments, regardless of quality grade, similar (P > 0.05) for ratings of juiciness, tenderness, flavor liking, and overall liking and were greater (P < 0.05) than all non-enhanced treatments. Among non-enhanced treatments, ratings of flavor liking and overall liking decreased (P < 0.05) as quality grade decreased. Non-enhanced Prime and Low Choice were similar (P > 0.05) for tenderness and juiciness, but were greater (P < 0.05) than non-enhanced Low Select. Consumers reported increased (P < 0.05) ratings of juiciness, tenderness, and overall liking as DOD decreased. All enhanced samples and non-enhanced Prime had a similar (P > 0.05) percentage rated acceptable for tenderness and juiciness. Non-enhanced Prime and Low Choice samples had a similar (P > 0.05) percentage of samples rated acceptable for tenderness, juiciness, flavor liking, and overall liking, but both were greater (P < 0.05) than non-enhanced Low Select. A greater (P < 0.05) percentage of samples were rated acceptable for tenderness, juiciness, and overall liking as DOD decreased. All enhanced samples had a similar (P > 0.05) percentage of samples classified as better than everyday quality and premium quality, but a higher (P < 0.05) proportion than all of the non-enhanced treatments. Instrumental tenderness measurements of SSF reported no differences (P > 0.05) across all treatments. No differences (P > 0.05) of PJP were reported for quality treatments of samples; however, values of PJP decreased (P < 0.05) as DOD increased.ConclusionThese results indicate enhancement has a substantial, positive effect on beef palatability; however, this improvement is not independent of marbling. Enhancement of higher quality beef does not provide an additive palatability benefit and, therefore, provides the most economic palatability advantage in lower quality beef products.