E.P. Berg

Characterizing beef muscles with optical scattering and absorption coefficients in VIS-NIR region.

We developed a fiber optical probe to measure spatially resolved diffuse reflectance from beef samples in VIS-NIR bandwidth of 450-950nm. The optical scattering and absorption coefficients were obtained by fitting the measurements with diffuse equation. Beef absorption coefficients are related to the sample chemical compositions such as the concentration of myoglobin and its derivatives; while scattering coefficients depend on meat structural properties such as sarcomere length and collagen concentration. Structural properties are also key factors in determining beef tenderness, therefore we hypothesize that a correlation exists between optical scattering and cooked Warner-Bratzler shear (WBS) force. Thirty-two, unfrozen beef muscle samples obtained from different animals were used in the correlation study. We found a higher scattering coefficient was associated with a higher cooked WBS. A linear regression analysis showed that sample scattering coefficients were significantly (p<0.0001) correlated to the corresponding WBS with a coefficient of determination (R(2)) of 0.59.

The influence of diets containing either conventional corn, conventional corn with choice white grease, high oil corn, or high oil high oleic corn on belly/bacon quality

The objectives of this study were to evaluate diets possessing different fatty acid profiles (as influenced by corn type) with regard to fatty acid profile and firmness of pork bellies. Crossbred barrows (n=196) were fed one of four corn-based diets consisting of conventional corn (CONV), CONV with choice white grease (CWG), high oil corn (HOC), or high oleic, high oil corn (HOHOC). Following 98 days on test, two animals representing the average pen weight (118 kg) were selected for harvest (n=56). A 50-g fat sample was removed from each belly for fatty acid profile analysis. Lateral and vertical flex tests were performed to determine belly firmness. Bellies were pumped and cooked according to a commercial protocol. Total saturated fatty acids increased (P<0.001) and total unsaturated fatty acids decreased (P<0.05) when CWG was added to the CONV diet or when HOC or HOHOC were substituted for CONV corn. Pigs fed CONV corn had firmer bellies, while those fed HOC were softer. No differences were observed across treatment for percentage pump retention, smokehouse yield, or slicing yield (P>0.05). Based on the results of this study, corn type influences fatty acid profile, and belly firmness, but does not affect pump retention, or slicing yields.

Predicting beef tenderness using color and multispectral image texture features

The objective of this study was to investigate the usefulness of raw meat surface characteristics (texture) in predicting cooked beef tenderness. Color and multispectral texture features, including 4 different wavelengths and 217 image texture features, were extracted from 2 laboratory-based multispectral camera imaging systems. Steaks were segregated into tough and tender classification groups based on Warner-Bratzler shear force. The texture features were submitted to STEPWISE multiple regression and support vector machine (SVM) analyses to establish prediction models for beef tenderness. A subsample (80%) of tender or tough classified steaks were used to train models which were then validated on the remaining (20%) test steaks. For color images, the SVM model correctly identified tender steaks with 100% accurately while the STEPWISE equation identified 94.9% of the tender steaks correctly. For multispectral images, the SVM model predicted 91% and STEPWISE predicted 87% average accuracy of beef tender.

Quantitation of hexanal by automated SPME for studying dietary influences on the oxidation of pork

Automated headspace solid-phase micro-extraction gas chromatography (auto-HS-SPME-GC) was employed to determine the hexanal content of ground pork shoulders from pigs raised on a normal corn diet and a corn diet high in oil and monounsaturated fatty acids. This external standard method showed good linearity (R2=0.999) and acceptable reproducibility (rsd=6.7%). Samples were stored refrigerated under light and analyzed on days 0, 3, 5, 7 and 9. Although no significant differences were observed between treatments in hexanal concentration, color, odor, or thiobarbituric acid-reactive substances (TBARS) value, TBARS and hexanal values increased over time, which became significant on days 7 and 9 for TBARS and on day 9 for hexanal. TBARS and hexanal concentration were correlated with R2 values of 0.992 and 0.804 for the treatment and control group, respectively. Auto-HS-SPME-GC provided a rapid and convenient method for monitoring the hexanal content of raw ground pork. HS-SPME using Carboxen/PDMS stable flex fiber provided the required sensitivity, linearity and reproducibility for measurement of hexanal in the headspace of raw ground pork.

Working chute behavior of feedlot cattle can be an indication of cattle temperament and beef carcass composition and quality

The relationship between working chute temperament and beef carcass quality traits were measured on 183 crossbred feedlot steers. Steers were weighed and sorted into 16 pens and weighed every 28 days. Temperament was evaluated as exit velocity (EV), chute score (CS), and catch score (CAPS). Tissue samples were collected for DNA profile including docility (IGENITY®, Merial Limited, Duluth, GA, U.S.A). Steers were harvested at 14 to 16 months of age (606 ± 52 kg). Exit velocity increased and CS and CAPS values declined over time. Steers receiving a lower CAPS score had more marbling (P = 0.02). Ribeye steaks from steers with a slow first recorded EV were more tender (P = 0.02) than steaks from faster EV steers. IGENITY® docility index had a positive (P = 0.09) correlation (r = 0.15) with Warner-Bratzler shear force (WBS) indicating a higher docility index was loosely associated with tougher meat.

2011 and 2012 Early Careers Achievement Awards: farm and pig factors affecting welfare during the marketing process.

The objective of this paper is to review the scientific literature to identify on-farm factors that contribute to market weight pig transportation losses. Transportation of market weight pigs is an essential element to the multisite pork production model used in the United States. In 2011 alone, approximately 111 million market weight pigs were transported from the finishing site to the abattoir. For pigs, the marketing process can present a combination of potentially novel, physical, and/or unfamiliar experiences that can be stressful. If the pig cannot cope with these sequential and additive stressors, then an increased rate of transportation losses could occur with a detrimental effect on pork carcass value. Current yearly estimates for transport losses are 1 million pigs (1%). A variety of market weight pig and farm factors have been reported to detrimentally affect transportation losses. By understanding how pigs interact with their environment during marketing, researchers, producers, and personnel at the abattoir may begin to identify, prioritize, and attempt to minimize or eliminate these stressors. This process will ultimately decrease transportation losses, improve pork quality, and increase profitability.

Prediction of troponin-T degradation using color image texture features in 10d aged beef longissimus steaks.

The objective was to use digital color image texture features to predict troponin-T degradation in beef. Image texture features, including 88 gray level co-occurrence texture features, 81 two-dimension fast Fourier transformation texture features, and 48 Gabor wavelet filter texture features, were extracted from color images of beef strip steaks (longissimus dorsi, n = 102) aged for 10d obtained using a digital camera and additional lighting. Steaks were designated degraded or not-degraded based on troponin-T degradation determined on d 3 and d 10 postmortem by immunoblotting. Statistical analysis (STEPWISE regression model) and artificial neural network (support vector machine model, SVM) methods were designed to classify protein degradation. The d 3 and d 10 STEPWISE models were 94% and 86% accurate, respectively, while the d 3 and d 10 SVM models were 63% and 71%, respectively, in predicting protein degradation in aged meat. STEPWISE and SVM models based on image texture features show potential to predict troponin-T degradation in meat.

Prediction of color and pH measurement throughout boneless center-cut pork loins.

Boneless pork loins (N=95) divided into three groupings based on National Pork Producers Council color standards were utilized to characterize changes in color and pH throughout the loin. CIE L(∗), CIE a(∗), CIE b(∗), saturation, and hue angle differed (P<0.05) for color category and chop position. A color category by position interaction (P<0.05) existed only for pH values. These differences in color and pH measures throughout the loin indicate that one measurement may not characterize the entire boneless loin. For all color and pH measures significant orthogonal and polynomial contrasts existed, therefore, separate regression equations were developed for each color category to predict position response. Multiple regression equations were significant for most objective measures of color and pH, but the low R(2) values indicate that these models provide little information as to changes in color and pH throughout the boneless pork loin.

Growth parameters and meat quality of finishing hogs supplemented with creatine monohydrate and a high glycemic carbohydrate for the last 30 days of production

The objective of this study was to evaluate the growth and meat quality of hogs supplemented with creatine monohydrate (CMH) and (or) a simple carbohydrate (dextrose) for the last 30 days of production. Crossbred market barrows (n=32; 75 kg) were blocked by weight and randomly allotted to one of eight pens with four animals per pen. Dietary treatments were a control (normal corn and soybean meal diet), CMH (control diet supplemented with 0.55% CMH), DEXT (control diet supplemented with 2.1% dextrose), and COMBO (control diet supplemented with CMH and DEXT). Average daily gain on test, fat depth, hot carcass weight, and LMA (postmortem dot grid measurement) were not affected by dietary treatment. However, a nonsignificant trend (P=0.07) was observed for 10th rib loin muscle area (LMA) gain on test as determined by real-time ultrasound comparisons over the course of the 30 days feeding duration (COMBO=4.24 cm(2) increase vs. control=1.0 cm(2) increase). No significant differences in pork quality were noted across treatment groups.

Effects of post-mortem aging time and type of aging on palatability of low marbled beef loins

The study objective was to evaluate the effect of post-mortem aging period (14 to 49days), dry vs. wet (D vs W) type of aging on the palatability of bone-in (BI) beef short loins (n=96) and boneless (BL) strip loins (n=96) possessing United States Department of Agriculture marbling scores between Slight and Small. Warner-Bratzler shear force (WBSF) scores decreased linearly over time (P=0.0001). WBSF was not influenced by aging method or loin type. Aged flavor was higher for DBL than for DBI with WBL and WBI intermediate. Dry aging strip loins increase aged flavor yet did not improve beefy flavor compared to wet aging. Based on objective data and panelists scores for tenderness, juiciness and aged flavor, a boneless, 28days wet aged strip steak, cooked to 71°C would provide the best combination of eating satisfaction and value.