Impact of nitrite-embedded packaging film on quality and sensory attributes of alternatively-cured and nitrite-free bologna.

The objectives were to determine the effects of post-thermal processing nitrite-embedded film (NEF) packaging on the quality attributes of alternatively-cured (nitrite from celery juice powder (AC)) and nitrite-free bologna. Attributes evaluated included lipid oxidation, instrumental color, pigment concentration, and sensory properties such as cured meat flavor, aroma, and color. Three bologna formulations, each packaged with two packaging films were produced. A conventionally-cured control formulation (with nitrite from sodium nitrite; CON), a nitrite-free formulation (UCC), and an alternatively cured formulation (nitrite from cultured celery juice powder; AC) were packaged in conventional (CF) or nitrite-embedded (NEF) film. Instrumental a* values (measured during both light and dark storage at intervals of 7 or 14 days over 126 days of storage) and cured pigment concentration (measured at 14-day intervals over 84 days of storage) were significantly greater (P < 0.05) for the UCC-NEF treatment compared to its conventional film counterpart, UCC-CF. No significant differences (P > 0.05) for lipid oxidation (TBARS values) were observed with NEF. Trained sensory panelists, who evaluated samples at 14-day intervals over 70 days of storage, found significantly greater (P < 0.05) cured aroma, cured flavor, pink color and less off-flavor for uncured bologna packaged in NEF compared to conventional film. For the uncured bologna formulation, NEF packaging provided cured meat attributes comparable to the control formulation that included nitrite. This is the first time that cured aroma and flavor have been observed when nitrite from packaging film is added to a cooked meat product under anaerobic conditions.

Effects of extended postmortem aging and intramuscular location on protein degradation, muscle fiber morphometrics, and tenderness of beef longissimus lumborum and semitendinosus steaks.

The objective of this study was to determine effects of extended aging and intramuscular location on Warner-Bratzler shear force (WBSF), muscle fiber cross-sectional area (CSA), and protein degradation of semitendinosus (ST) and longissimus lumborum (LL) steaks. Left ST and LL were removed from 40 carcasses at 6 d postmortem. The ST was fabricated into five locations (LOC), with LOC 1 being most proximal and LOC 5 being most distal. The posterior LL was fabricated into 3 LOC, with LOC 1 being most anterior. Vacuum sealed ST steaks were aged 7, 14, 28, 56, or 112 d postmortem, while LL steaks were aged 7, 28, or 112 d postmortem at 2 ± 1 °C. A steak from each LOC was assigned to WBSF or laboratory analyses. There were no Day of Aging (DOA) × LOC interactions for all dependent variables (P > 0.06). There were DOA effects for ST and LL WBSF values and degraded 38-kDa desmin (DES; P < 0.01). Day-7 ST-steak WBSF value was greater than all other days (P < 0.01) and day-14 steaks had greater WBSF value than remaining days (P < 0.05). Day-28 ST-steak WBSF values were greater than day 56 and 112 (P < 0.01), which did not differ (P = 0.53). In the LL, day-7 steaks had greater WBSF values than the other two timepoints (P < 0.01) and day-28 steaks had greater (P < 0.01) WBSF values than day-112 steaks. Degraded ST 38-kDa DES content was less on day 7 and 14 compared to all other days (P < 0.03), but did not differ (P = 0.79) from each other. Days 28 and 56 38-kDa DES content was less than day 112 (P < 0.01), but did not differ (P = 0.34) from each other. Degraded LL 38-kDa DES content was less on day 7 than day 28 and 112 (P < 0.02), which did not differ (P = 0.67). There were LOC effects for only ST WBSF and muscle fiber CSA (P < 0.05). Semitendinosus steak LOC 1 and 2 had greater WBSF values than all other locations (P < 0.01), but did not differ (P = 0.32) from each other. Semitendinosus steak LOC 3 and 5 had greater WBSF values than LOC 4 (P < 0.01), but did not differ (P = 0.85) from each other. The CSA of all ST fiber types were largest in LOC 1 compared to all other fiber types (P < 0.01). The CSA of all LOC 2 and 3 fiber types was greater than LOC 4 and 5 (P < 0.01), but were not different from each other (P > 0.81), and LOC 4 had greater CSA than LOC 5 (P < 0.01). Steak aging WBSF value improvements seemed proteolysis catalyzed, while the ST intramuscular tenderness gradient was more likely due to muscle fiber CSA.

Measurement of the three-axis vibration, temperature, and relative humidity profiles of commercial transport trailers for pigs.

The objective of this study was to collect and interpret three-axis acceleration, temperature, and relative humidity data from six locations within commercial transport trailers shipping market-weight pigs. Transport was observed in Kansas (n = 15) and North Carolina (n = 20). Prior to loading, three-axis accelerometers were affixed to six locations on the trailers: top fore (TF), top center (TC), top aft (TA), bottom fore (BF), bottom center (BC), and bottom aft (BA) compartments. Data were post-processed to calculate root-mean-square (RMS) accelerations and vibration dose values (VDV) in the vertical direction and the horizontal plane. These values were compared with exposure action values (EAV) and exposure limit values (ELV), vibration levels deemed uncomfortable and potentially dangerous to humans. Additionally, RMS and VDV were compared among the trailer compartments. The vertical RMS accelerations for all compartments exceeded the EAV for loads measured in Kansas, and for the majority of the compartments measured in North Carolina. Many compartments, specifically the BA compartment from all trips, exceeded the vertical ELV. Regardless of where the data were collected, fewer compartments exceeded the EAV in the horizontal orientation. Only BA compartments exceeded the ELV in the horizontal orientation. There were Area × Level interactions for vertical and horizontal RMS and VDV (P < 0.01). The BF compartment had a greater vertical RMS value than the TF, TC, and BC (P < 0.02) compartments, but did not differ (P = 0.06) from the TA compartment. The vertical RMS of the TA compartment did not differ from the TF, TC, and BC compartments (P > 0.13). The BF compartment had a greater (P = 0.02) vertical VDV value than the TC location, but did not differ from the other locations (P > 0.16). All other locations did not differ in vertical VDV (P > 0.12). The BF compartment had greater horizontal RMS than the TC and TA compartments (P < 0.01), but did not differ from TF and BC compartments (P > 0.12). All other compartments did not differ in horizontal RMS (P > 0.34). All compartments, aside from the BA compartment, did not differ in horizontal VDV (P > 0.19). Vibration analyses indicated the BA compartment had the greatest vertical and horizontal vibrations and a large percentage of the compartments exceed the EAV and ELV, which indicated pigs may have experienced uncomfortable trips that could cause discomfort or fatigue.

Effects of supplementing docosahexaenoic acid-rich microalgae and antioxidants on beef longissimus lumborum steak color stability and sensory characteristics.

The objective of this study was to determine the effects of four microalgae and antioxidant feeding regimens on beef longissimus lumborum color stability and palatability. Steers were blocked by weight and randomly assigned to one of four dietary treatments fed during a 45-d feeding period. Treatments (n = 10 per treatment) consisted of a control diet (CON) and control diet plus 100 g∙steer-1∙d-1 microalgae (ALGAE), ALGAE plus antioxidants (103 IU/d vitamin E and Sel-Plex) fed throughout feeding (AOX), and AOX fed for the final 10 d of finishing (LATE). The longissimus lumborum muscle was removed, aged for 14 d, and fabricated into steaks for objective and subjective color and palatability analyses. There were treatment × day of display interactions for a* value and steak surface metmyoglobin percentage (P < 0.01). There were no treatment differences through day 4 of display for a* value (P > 0.16) and day 5 of display for surface metmyoglobin (P > 0.10). By day 10 of display, ALGAE steaks had a smaller a* value than all other treatments (P < 0.01). Steaks from AOX steers had a greater (P < 0.01) a* value than CON steaks, whereas both a* values did not differ from LATE steaks (P > 0.19). By the end of display, ALGAE steaks had more metmyoglobin than the other treatments (P < 0.01). Steaks from AOX steers had less metmyoglobin than CON and LATE steaks (P < 0.04), which did not differ (P > 0.25). Treatment did not affect trained panel ratings (P > 0.15); however, treatment did affect (P < 0.01) off-flavor intensity. Steaks from ALGAE and AOX steers had greater off-flavor ratings than CON steaks (P < 0.03), but did not differ (P = 0.10). Steaks from LATE steers did not differ in off-flavor ratings from the other treatments (P > 0.07). Use of antioxidants improved color stability of steaks from microalgae fed steers; however, panelists still detected off-flavors.

The effects of the LIPEX finishing diet regimen on pork quality, fatty acid profile, palatability, and color stability.

The objective of this study was to determine the effects of the LIPEX finishing diet regimen on pork chop n-3 polyunsaturated fatty acid (PUFA) content and fresh meat quality. Twenty-eight finishing pigs (PIC 359 × F1 Hermitage/NGT; initial BW 81.5 ± 2.55 kg) were subjected to a 49-d feeding trial. Treatments consisted of a 2 × 2 factorial design with Sex (n = 14 barrows and gilts each) and Diet as main effects. Dietary treatments consisted of a 2-phase standard finishing diet regimen or a 2-phase LIPEX finishing diet regimen (EXL Milling, Lloydminster, SK, Canada). The LIPEX diet regimen added the EXL LIPEX.FA369 additive during phase 1 and the EXL LIPEX.FA369 and XFE Omega-3 Finishing Touch during phase 2. Five-days postmortem, whole boneless pork loins were transported to the Kansas State University Meats Laboratory, aged 14 d, and halved immediately behind the spinalis dorsi. After blooming for 30 min, chops were evaluated for Japanese color score and National Pork Producers Council (NPPC) color and marbling scores. A 2.54-cm chop was taken immediately anterior to the loin cut and was used for fatty acid and proximate composition analyses. Four 2.54-cm chops were cut from the posterior portion of the loin and were utilized for a 7-d simulated retail display analyses, Warner-Bratzler shear force (WBSF), and trained sensory panel. There were no Sex × Diet interactions for all variables measured in the study (P > 0.10). The LIPEX finishing regimen increased chop C18:3n-3, C20:5, and C22:5, which decreased the n-6:n-3 ratio (P < 0.01). There were no Diet effects on pH, Japanese and NPPC color and marbling scores, and proximate composition (P > 0.23). Diet did not affect cook loss, WBSF, and trained sensory panel scores (P > 0.012). There were no 2- or 3-way interactions between Diet, Sex, and Day, or Diet and Sex main effects for L*a* values, surface oxy- and metmyoglobin percentages, or visual panel chop redness and surface discoloration scores (P > 0.14). Feeding the LIPEX finishing diet regimen increased chop n-3 PUFA content without negatively impacting fresh chop palatability or color stability.

Amino acids effects on heterocyclic amines formation and physicochemical properties in pan-fried beef patties.

The effects of surface application of amino acids on the formation of heterocyclic amines (HCAs) and meat quality properties were evaluated in pan-fried beef patties (230 °C/15 min). Tryptophan, lysine, leucine, and proline at three concentrations, 0.05%, 0.20%, and 0.50% (w/w), were tested. The meat crusts were analyzed for HCA content using liquid chromatography-tandem mass spectrometry. Results showed that surface application of all tested amino acids significantly reduced total HCA content (P < 0.05), and the interaction of amino acid type and concentration significantly affected (P < 0.05) both individual and total HCA formation. Tryptophan at 0.50% reduced total HCAs the most (0.92 ng/g, 93% inhibition), followed by 0.50% lysine (1.94 ng/g, 84% inhibition), while leucine (3.95 ng/g, 64% inhibition) and proline (4.71 ng/g, 56% inhibition) were less effective at 0.50%. In addition, applying amino acids to meat surface significantly influenced (P < 0.05) pH and surface color change of beef crusts; particularly, lysine at 0.20% and 0.50% increased pH and a* (redness) but reduced b* (yellowness), while tryptophan and leucine at 0.50% increased L* (whiteness). No significant effect was observed on cooking loss. Adding amino acids at 0.50% affected (P < 0.05) formation of aldehydes and pyrazines (as the key flavor compounds of fried beef). Overall, the results of this study suggested that adding amino acids to ground beef patties could effectively mitigate mutagenic HCA formation during cooking.

Effects of quality grade and intramuscular location on beef semitendinosus muscle fiber characteristics, NADH content, and color stability.

The objective of this study was to determine the impact of quality grade and steak location on color stability of semitendinosus (ST) steaks during a 9-d refrigerated study. Twenty-one ST muscles (12 Choice and 9 Select) were purchased from a commercial beef packing plant and fabricated into twelve 2.54-cm thick steaks per muscle. Steaks 1, 6, and 12 were designated for immunohistochemistry while remaining steak locations of proximal (steaks 2 to 4), middle (5 to 8), and distal (9 to 11) were randomly assigned to 0, 4, or 9 d of simulated retail display. Surface color attributes of day-9 steaks were recorded daily by a visual color panel and spectrophotometer. On days 0, 4, and 9 of display, steaks were analyzed for metmyoglobin reducing ability (MRA) and oxygen consumption (OC). Grade × day of display (DOD) interactions were detected for L*, a*, surface oxymyoglobin (OMb) and metmyoglobin (MMb) percentages, and visual panel surface redness and discoloration scores (P ≤ 0.02); however, no Grade × DOD interactions were observed for MRA or OC (P > 0.17). There were location main effect (LOC) × DOD interactions for L*, a*, surface MMb, visual panel surface redness and discoloration, and MRA (P ≤ 0.02). Distal steaks had lower L* values compared with the other locations (P < 0.01), which coincided with steaks being rated visually darker red (P < 0.01). Proximal steaks had greater a* values and had less surface discoloration than middle steaks (P < 0.05), which had an increased percentage of surface MMb (P ≤ 0.04). Distal and proximal steaks had increased MRA compared with middle steaks on days 0 and 4 (P < 0.05), and distal steaks had greater OC than the other locations throughout display (P < 0.01). There were fewer type I fibers at the proximal end with a greater percentage located at the middle and distal ends, and an increased percentage of type IIX fibers at the middle and proximal locations (P ≤ 0.01). Less type IIA fibers were detected at the middle LOC compared with the other two locations (P < 0.10). Larger type I, IIA, and IIX fibers were located at the proximal and middle locations compared with the distal LOC (P < 0.01). ST color and color-stability characteristics were influenced by DOD and LOC, which may partially be explained by differences in fiber types among locations.

Evaluation of marbling and enhancement's abilities to compensate for reduced beef palatability at elevated degrees of doneness.

The objectives of this study were to evaluate the extent marbling compensates for reduced beef palatability at elevated degrees of doneness and to determine the relationship of residual moisture and fat in cooked steaks to beef palatability, specifically beef juiciness. Paired strip loins (IMPS # 180) were collected to equally represent five quality treatments [Prime, Top Choice (modest and moderate marbling), Low Choice, Select, and Select Enhanced (110% of raw weight)]. Steaks were grouped into sets of three consecutively cut steaks and randomly assigned a degree of doneness (DOD): very-rare (VR; 55 °C), rare (R; 60 °C), medium-rare (MR; 63 °C), medium (M; 71 °C), well done (WD; 77 °C), or very well done (VWD; 82 °C). Samples were subjected to consumer and trained sensory evaluation, Warner-Braztler shear force (WBSF), slice shear force (SSF), pressed juice percentage (PJP) evaluation, and raw and cooked proximate analysis. There were no (P > 0.05) quality treatment × DOD interactions for consumer sensory ratings, indicating increased DOD had the same negative impact regardless of marbling level. There was a quality treatment × DOD interaction (P < 0.05) for the percentage of steaks rated acceptable by consumers for juiciness. Increased marbling modified the point in which steaks became unacceptable for juiciness. Similarly, there was a quality treatment × DOD interaction (P < 0.05) for trained juiciness ratings. When cooked to MR and lower, Prime was rated only 8% to 18% higher (P < 0.05) than Select for trained juiciness ratings, but was rated 38% to 123% higher (P < 0.05) than Select when cooked to M and higher. Besides cooking loss, combined cooked moisture and fat percentage was more highly associated (P < 0.01) to consumer juiciness (r = 0.69) and trained initial (r = 0.84) and sustained (r = 0.85) juiciness ratings than all other objective evaluations. Using regression analyses, cooked moisture and fat percentages, alone, were poor indicators of consumer and trained juiciness ratings. However, when combined, the regression equations explained 45%, 74%, and 69% of the variation in consumer, trained initial, and trained sustained juiciness ratings, respectively. These results indicate that increased marbling levels only offer "insurance" for juiciness of steaks that are cooked to high degrees of doneness, but not for other palatability traits. Additionally, cooked residual moisture and fat percentages, when combined, are a good indicator of sensory juiciness ratings.

Effect of enhancement on the formation of heterocyclic amines in cooked pork loins: preliminary studies.

Heterocyclic amines (HCAs) which are produced in meats cooked at high temperature a risk factor for certain human cancers. This study evaluated the effect of enhancement on HCA formation in cooked pork loins. Three samples of pork loin were prepared including non-injected loin, 12% water-injected loin, and 12% salt/phosphate injected loin. The HCAs were identified in all samples: PhIP (2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine), MeIQx (2-amino-3,8-dimethylimidazo [4,5-f]quinoxaline), and DiMeIQx (2-amino-3,4,8-trimethylimidazo [4,5-f]quinoxaline). Injection of salt/phosphate significantly reduced the level of PhIP by 42.7%, MeIQx by 79.0%, and DiMeIQx by 75.0%. Enhancement with water alone did not reduce HCA formation.

Incidence and severity of Arcanobacterium pyogenes injection site abscesses with needle or needle-free injection.

Nursery-age pigs (n=198) were used to evaluate the difference in abscess formation at needle-free jet and conventional needle-and-syringe injection sites. Needle-free jet injection was used to administer injections in the neck and ham on one side of the animal whereas needle-and-syringe was used for neck and ham injections on the opposite side. Immediately prior to injection, the injection site surfaces were contaminated with an inoculum of Arcanobacterium pyogenes. Each pig was humanely euthanized 27 or 28 days after injections. Histopathological results showed that needle-free jet injection was associated with more abscesses than needle-and-syringe injection at both neck (P=0.0625) and ham (P=0.0313) injection sites. Out of 792 injection sites, only 13 abscesses were observed, with 12 of those present at needle-free jet injection sites. Needle-free jet injection may increase the occurrence of injection site abscesses that necessitate carcass trimming at pork processing plants.

Occurrence of heterocyclic amines in cooked meat products.

Heterocyclic amines (HCAs), potent mutagens and a risk factor for human cancers, are produced in meats cooked at high temperature. The aim of this study was to determine the HCA content in cooked meat products (beef, chicken, pork, fish) prepared by various cooking methods (pan frying, oven broiling, and oven baking at 170 to 230°C) that are preferred by U.S. meat consumers. The primary HCAs in these samples were PhIP (2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine) (1.49-10.89ng/g), MeIQx (2-amino-3,8-dimethylimidazo [4,5-f]quinoxaline) (not detected-4.0ng/g), and DiMeIQx (2-amino-3,4,8-trimethyl-imidazo [4,5-f]quinoxaline) (not detected-3.57ng/g). Type and content of HCAs in cooked meat samples were highly dependent on cooking conditions. The total HCA content in well-done meat was 3.5 times higher than that of medium-rare meat. Fried pork (13.91ng/g) had higher levels of total HCAs than fried beef (8.92ng/g) and fried chicken (7.00ng/g). Among the samples, fried bacon contained the highest total HCA content (17.59ng/g).

Heterocyclic amine content in commercial ready to eat meat products.

Heterocyclic amines (HCAs) are produced in meats cooked at high temperature, which are potent mutagens and a risk factor for human cancers. The aim of this study was to estimate the amount of HCAs in some commonly consumed ready-to-eat (RTE) meat products. The RTE products were purchased from a local grocery store, and HCA were analyzed using an analytical method based on solid-phase extraction followed by HPLC. The primary HCAs in these samples were PhIP (2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine) (not detected-7.9 ng/g) and MeIQx (2-amino-3,8-dimethylimidazo [4,5-f]quinoxaline) (not detected-3.6 ng/g). Products ranked in order of increasing total HCA content: pepperoni (0.05 ng/g)

Kinetics of myoglobin redox form stabilization by malate dehydrogenase.

This study reports the reduction of metmyoglobin (MMb) via oxidation of malate to oxaloacetate and the regeneration of reduced nicotinamide adenine dinucleotide (NADH) via malate dehydrogenase (MDH). Two experiments were conducted to evaluate a malate-MDH-NADH system as a possible mechanism for MMb reduction. In experiment 1, kinetics of MDH and MMb reduction were determined, and the results showed that increasing concentrations of oxidized nicotinamide adenine dinucleotide (NAD(+)) and l-malate also increased (p < 0.05) MMb reduction in vitro. Experiment 2 assessed the reducing activity of beef muscle extracts with different concentrations of malate and NAD(+) added. Reduction of MMb in the muscle extracts via MDH was NAD(+), malate, and extract concentration dependent (p < 0.05). A new mechanism is described for the nonspecific and specific enzymatic reduction of MMb, which supports the hypothesis that malate can replenish NADH via MDH activity in post-mortem muscle, ultimately resulting in a more functional meat color.

Myoglobin redox form stabilization by compartmentalized lactate and malate dehydrogenases.

The purpose of this study was to assess the ability of mitochondrial and cytoplasmic malate dehydrogenase present in postrigor bovine skeletal muscle to use malate as a substrate for reduced nicotinamide adenine dinucleotide (NADH) regeneration and metmyoglobin (MMb) reduction via the malate-NAD(+)-MMb system. Furthermore, addition of lactate to beef mitochondrial and cytoplasmic isolates was evaluated to determine whether interactions between malate and lactate increased MMb reduction. Addition of malate to isolated beef mitochondrial and cytoplasmic isolates at pH 7.2 increased (p < 0.05) MMb reduction. MMb reduction resulting from addition of malate and lactate was equal to or greater than MMb reduction resulting from malate alone. This suggests that a combination of mitochondrial (malate) and cytoplasmic (lactate) factors can be used to regenerate the post-mortem pool of NADH, resulting in metmyoglobin reduction and meat color stabilization.

Effectiveness of transdermal, needle-free injections for reducing pork carcass defects.

A needle-free, transdermal injection device was evaluated for effectiveness of vaccine delivery and for injection site lesions in swine. A total of 130 pigs were vaccinated for pseudorabies virus (PRV) and Mycoplasma hyopneumoniae (M. hyopneumoniae). Pigs were divided into three groups; one group served as unvaccinated controls, the second group was vaccinated with conventional hypodermic needles and the third group was vaccinated with a needle-free, airpowered transdermal injection device. Blood samples collected for up to 36 days post-injection showed that both injection methods produced similar serological responses that were significantly greater than for unvaccinated controls. Injection sites, collected at slaughter from each carcass, showed minimal development of lesions and no carcass defects. The results show the needle-free, transdermal injection system to be effective and safe. Elimination of needles will prevent residual needle fragments in carcasses and associated carcass defects that develop from needle-induced injection-site lesions.