Relationship of Warner-Bratzler shear force and trained sensory panel tenderness of strip loin steaks cooked to 131 and 158°F

In a previous study, eighteen strip loins from USDA Select and premium Choice carcasses were cooked on a Magikitch’n® belt grill to determine tenderness at nine different endpoint temperatures. That study revealed that optimum Warner-Bratzler shear force (WBSF) values occurred in strip loin steaks cooked to 131°F, but current WBSF protocol requires steaks to be cooked to 158°F. Therefore, trials employing trained sensory panels (TSP) were conducted to determine the relationship of WBSF with TSP tenderness from steaks cooked to 131 and 158°F on the belt grill. As expected, panelists found steaks cooked to 131°F more tender than those cooked to 158°F. The relationship of WBSF with TSP ratings for tenderness was not significant (P>0.05) when both steaks were cooked to 158°F. When both steaks were cooked to 131°F, however, there was a moderate relationship (r = -0.52) of WBSF with TSP tenderness. The relationship of WBSF from steaks cooked to 131°F with TSP ratings for tenderness from steaks cooked to 158°F was the strongest (r = -0.66). More research is needed to determine the feasibility of cooking steaks to 131°F, rather than 158°F, to improve WBSF determination

Endpoint temperature, cooking method, and marbling degree have different effects on Warner-Bratzler shear force of beef strip loin, bottom round, and brisket muscles

Our objective was to determine the effects of endpoint temperature, cooking method, and marbling on Warner-Bratzler shear force (WBSF; an objective method for determining tenderness) of three beef muscles. Eighteen subprimals of a muscle containing low content of connective tissue, longissimus lumborum (strip loin), and two muscles containing a high content of connective tissue, biceps femoris (bottom round) and deep pectoralis (brisket), were selected from USDA Select and Choice (Certified Angus Beef) carcasses. After 14 days of aging, subprimals were frozen, fabricated into steaks, and stored frozen until cooking. Steaks were assigned to one of two cooking methods, the Magikitch’n® electric belt grill (a rapid conduction method) or a water bath (a slower, convection method); and one of nine endpoint cooking temperatures, 104, 113, 122, 131, 140, 149, 158, 167, or 176°F. According to WBSF results, optimum tenderness for the strip loin occurred around 131°F. Higher marbling protected tenderness at higher endpoint temperatures. Tenderness increased in bottom round and brisket muscles as endpoint temperature increased from 104 to 140°F, then tenderness decreased as endpoint temperature rose from 149 to 176°F. Endpoint temperature was the only significant factor affecting bottom round tenderness. Steaks cooked in the water bath had higher WBSF and, therefore, were less tender than those cooked on the belt grill. This was true for both the strip loin and brisket. The effect of increasing endpoint temperature on WBSF of the strip loin was different than for the bottom round and brisket

Effects of packaging on bone marrow discoloration in beef arm, rib, shoulder blade, and thoracic vertebra bones

Meat retailers have reported bone marrow discoloration to be a problem, especially in modified-atmosphere packages (MAP). To evaluate causes of bone marrow discoloration in different beef bones and packaging systems, 36 beef arm bones, ribs, shoulder blades, and thoracic vertebrae from USDA Select and Choice carcasses were obtained from a commercial abattoir, cut into 1-inch-thick sections at 4 days postmortem, and packaged into 1) polyvinyl chloride film (PVC) overwrap; 2) high-oxygen (80% O2, 20% CO2) MAP; or 3) ultra-low-oxygen (70% N2, 30% CO2) MAP. Packages were displayed under continuous fluorescent lighting for 4 days at 35.6°F. Ribs, shoulder blades, and thoracic vertebrae packaged in PVC and high-oxygen MAP developed undesirable gray or black discoloration during display. In ultra-low-oxygen MAP, mean visual-color scores were acceptable throughout display. The a* values (larger values equate to redder color) for ribs, shoulder blades, and thoracic vertebrae decreased (P<0.05) over time. Arm-bone marrow had less oxidation and dramatically less total iron and hemoglobin than did marrow from ribs and thoracic vertebrae. The much larger amounts of iron and hemoglobin in ribs and thoracic vertebrae likely correspond to marrow discoloration. In summary, bone marrow discoloration occurs in ribs, shoulder blades, and thoracic vertebrae packaged in PVC or high-oxygen MAP. Bones packaged in ultralow- oxygen MAP or arm bones packaged in PVC or high-oxygen MAP had minimal oxidation and discoloration

Needle-free injection enhancement of beef improves tenderness but slightly increases microbial translocation

Blade tenderization has been used for decades to increase tenderness in beef cuts that are highly variable in tenderness or predicted to be “tough.” Injection enhancement also is commonly used in industry to increase tenderness, juiciness, and flavor of some beef muscles. These processes have the potential to translocate microbial organisms on the exterior to interior portions of whole muscles. One research study reported that 3 to 4% of surface bacteria are transferred into the interior of muscles but only penetrate an average of ¼ inch deep into the surface. Even though the frequency of subprimal surfaces being contaminated with pathogens is low, translocation of these contaminants into the interior of subprimals by tenderization or injection procedures poses a public health risk. Microbial contamination on beef surfaces generally is eliminated during typical cooking; however, given the low infectious doses of pathogens such as Escherichia coli O157:H7, internalized contamination may survive if adequate temperatures are not reached at the center of cuts (i.e., rare and medium rare endpoints) and lead to illness. Industry groups have developed a guide, Best Practices: Pathogen Control During Tenderizing/Enhancing of Whole Muscle Cuts to minimize any hazard that may be present with such technologies. Although needle injection enhancement currently is common in beef processing, there may be alternative, safer, or more effective means to apply these technologies. One potential method involves utilizing an air-pressured needle-free injection system similar to an instrument currently being investigated for use in vaccinating cattle. In theory, eliminating the need for physical penetration of the muscle with a needle-free instrument using air-pressure fluid streams would reduce the translocation of surface microbial contamination to the interior and would additionally minimize carryover contamination from subprimal to subprimal during continuous injection operations. Therefore, we investigated use of needle-free injection enhancement as an alternative strategy to needle injection enhancement. Our objectives were to determine the safety and efficacy of using needle-free injection for enhancing beef muscles and the application of needle-free injection enhancement for improving beef quality

Packaging atmospheres alter beef tenderness, fresh color stability, and internal cooked color

Several meat quality traits affect consumers’ overall purchase decisions and satisfaction with meat products, but color is the major factor affecting purchasing decisions. According to some researchers, tenderness is the most important palatability attribute in consumers’ overall eating experience. Case-ready packaging in the meat industry is growing at a rapid rate and generally includes modified atmosphere packaging (MAP) with specific gases. Advantages of MAP include use of a centralized location, improved sanitation control, more consistent products, and increased marketing flexibility. Packaging beef in highoxygen (HiO2) MAP results in a desirable bright red lean color but can have detrimental effects on other quality traits, including increased off-flavors and decreased tenderness. Use of carbon monoxide (CO) has been approved by USDA and the Food and Drug Administration for use at levels up to 0.4% in retail MAP. Products in MAP that include CO have improved beef color stability and extended display time. Premature browning, originally discovered in ground beef, results when meat is cooked to temperatures lower than what is necessary to kill harmful pathogens but appears well done internally. This phenomenon is also found in whole muscle steaks and can be attributed to packaging environments, including HiO2 MAP. Therefore, objectives of our study were to evaluate the effects of different gas compositions in different MAP systems vs. vacuum packaging on grain finished beef tenderness, display color stability, and internal cooked color

Relationship of total iron content in beef to flavor attributes

The objective of our study was to evaluate the relationships among total iron content, myoglobin/total iron ratio, hemoglobin/total iron ratio, and flavor attributes in beef top sirloin, shoulder clod, and tenderloin muscles. Top sirloin (n=74), shoulder clod (n=68), and tenderloin (n=73) muscles from A or B maturity carcasses that were either USDA Slight or USDA Small marbling and of either normal pH (6.0) were vacuum packaged, aged 35 days at 35ºF, and stored at -4ºF until analysis. A well trained, flavorprofile sensory panel determined flavor attributes on charbroiled steaks. Flavor attributes included beef flavor identification, bloody/serumy, brown roasted, livery, metallic, rancid, and sour. Concentrations of myoglobin and hemoglobin were determined by using high-pressure liquid chromatography. Total iron concentration was determined by using an atomic absorption spectrophotometer. The shoulder clod had greater total iron (P<0.05) than the top sirloin or tenderloin. Livery flavor increased (P<0.05) and beef flavor identification and brown roasted flavor decreased (P<0.05) in the top sirloin as total iron increased. Compared with the top sirloin and shoulder clod, the tenderloin had lower (P<0.05) myoglobin/total iron ratios and greater (P<0.05) hemoglobin/total iron ratios. At medium and high myoglobin/total iron ratios, samples with Slight marbling had more (P<0.05) livery flavor. At low myoglobin/total iron ratios, A-maturity samples had more (P<0.05) rancid off-flavor than B maturity samples. There were no relationships between hemoglobin/total iron ratios and flavor attributes. Total iron may contribute to livery flavor in the top sirloin, but total iron is not a reliable indicator of livery flavor

Packaging atmospheres and injection enhancement affect beef tenderness and sensory traits

Case-ready meat provides many benefits, including quality and safety. Meat packaged in high-oxygen (HiO2) modified atmosphere packaging (MAP) has a desirable bright red display color but may have increased off- flavors and decreased tenderness. According to several international research reports, steaks aged and packaged in HiO2 MAP had more off-flavor, including warmed-over flavor, and were less tender and juicy than steaks aged in vacuum packaging (VP). Research at Kansas State University found that injection-enhanced beef quadriceps muscles packaged in HiO2 MAP were less tender and had more offflavors than those in ultra-low oxygen MAP. Detrimental effects of O2 on tenderness might be caused by protein oxidation. Oxidation of beef muscle proteins early postmortem inactivates the primary enzyme (μ-calpain) necessary to break down proteins postmortem, which results in decreased myofibrillar proteolysis and limited tenderization. Injection-enhancement improves tenderness and juiciness while decreasing variation and often is used in conjunction with MAP. Several studies have reported that enhanced steaks were more tender and juicy than non-enhanced steaks. Several researchers found an increase in beef flavor associated with enhanced steaks, but others have reported a decreased or no change in beef flavor. Offflavors associated with enhanced beef include salty and oxidative. Objectives of our study were to determine the effects of packaging atmosphere and injection-enhancement on beef strip loin, eye of round, and chuck clod tenderness, sensory traits, and desmin degradation

Effects of antioxidants on bone marrow discoloration in beef lumbar vertebrae in different packaging systems

To evaluate how antioxidants might prevent bone marrow discoloration, beef lumbar vertebrae held at 35.6°F for 6 or 14 days postmortem before packaging were cut into 1- inch-thick sections and packaged into 1) PVC overwrap; 2) high-oxygen (80% O2, 20% CO2) modified atmosphere packages (MAP); or 3) ultra-low-oxygen (70% N2, 30% CO2) MAP. Before packaging, bones were treated with: no treatment application (control); 1.25% or 2.5% ascorbic acid; 0.1% or 0.2% rosemary; or a combination treatment of 0.15% Origanox™ + 0.3% ascorbic acid. Packages were displayed under continuous fluorescent lighting for 4 days at 35.6°F. Untreated lumbar vertebrae and those treated with 0.1 or 0.2% rosemary discolored to gray or grayish-black, as measured by visual color scores and instrumental a* values, in PVC and high-oxygen MAP. The 1.25% ascorbic acid and 0.15% Origanox™ + 0.3% ascorbic acid were able to maintain desirable color scores through day 2 of display in PVC and high-oxygen MAP, but not after 4 days. The 2.5% ascorbic acid treatment was most effective in preventing discoloration and maintaining initial color in both PVC and high-oxygen MAP. In ultra-low-oxygen MAP, the 1.25% ascorbic acid treatment was as effective as the 2.5% ascorbic acid treatment in preventing bone marrow discoloration. In general, discoloration tended to be greater in bones held 14 days postmortem before packaging than in those held 6 days. Ascorbic acid treatments, particularly the 2.5% application, were effective in preventing bone marrow discoloration

Needle-free injection enhancement of beef strip loins with phosphate and salt has potential to improve yield, tenderness, and juiciness but harm texture and flavor

Meat tenderness is the most important palatability attribute affecting consumers’ overall eating experience. Injection enhancement and blade tenderization have long been used to improve this important trait. Injection enhancement has been shown to improve tenderness, juiciness, color stability, and cooking yield, but not all solutions have been adequately evaluated. Thus, there is a need to conduct research on the effectiveness of common enhancement solutions. We published results from an extensive study comparing a solution of phosphate, salt, and rosemary with a solution of calcium lactate and rosemary injected by using traditional needle injection. There were no differences in Warner-Bratzler shear force values between treatments, but trained panelists scored steaks enhanced with calcium lactate and rosemary to be less tender and juicy than steaks enhanced with phosphate, salt, and rosemary. However, steaks enhanced with the phosphate solution had a higher incidence of metallic and salty off-flavors, a darker initial color, and more color deterioration. Because needle-free injection enhancement is relatively similar to traditional needle-injection enhancement with regard to food safety, it should be evaluated for its effects on meat color, instrumental tenderness, sensory traits, and yields. Objectives of this research were to determine the effects of injection method (needlefree vs. needle injection) and solution (calcium lactate vs. phosphate solution) on meat color, instrumental tenderness, sensory traits, pump yield, and cooking loss of beef Longissimus lumborum muscles