Interrelationships among evaluations of beef longissimus and semitendinosus muscle tenderness by Warner-Bratzler shear force, a descriptive-texture profile sensory panel, and a descriptive attribute sensory panel.
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The objective of our study was to examine the interrelationships among Warner-Bratzler shear force (WBSF) determinations, evaluation by a highly trained descriptive-texture-profile (DTP) sensory panel, and evaluation by a trained descriptive attribute (DA) sensory panel as affected by muscle fiber orientation of samples and shear-blade type. Longissimus lumborum and semitendinosus muscles (n = 18 of each) were cut into 2.54-cm steaks, which were cooked to 71 degrees C. Cores were obtained with two methods (parallel to the muscle fiber orientation and perpendicular to the cut steak surface), used for WBSF determinations with the typical V-shaped blade and modified WBSF determinations with a flat blade, and presented to the DTP and DA sensory panels. The V-shaped blade resulted in 1.4 to 2.5 kg lower (P < .05) mean WBSF values than the flat blade for both muscles. Cores taken parallel to the longissimus muscle fiber orientation had .64 kg higher (P < .05) mean WBSF values than cores taken perpendicular to the cut steak surface. Both panels detected differences among carcass replications; however, a panelist x replication effect (P < .05) occurred for the DA panel. Both panels detected differences (P < .05) in muscle fiber orientation for attributes related to tenderness. Correlations between sensory panel scores and WBSF values were dependent on blade type and coring method. Blade type and coring method had greater effects on correlations between sensory scores and WBSF values for the DTP panel than for the DA panel. Correlations between scores by both sensory panels and WBSF values were comparable. The more highly trained DTP panelists were more consistent in their evaluations of texture attributes; however, they were more sensitive to muscle fiber orientation. Both panels were effective in detecting differences among carcass replications. (+info)
Vitamin D3 supplementation of beef steers increases longissimus tenderness.
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The objectives of these experiments were to determine 1) the effectiveness of supplemental vitamin D3 (VITD) on altering plasma and muscle calcium levels, 2) whether VITD supplementation improves Warner-Bratzler shear force (WBS) values of steaks from feedlot beef steers, and 3) the tenderness response curve of longissimus steaks from steers supplemented with VITD. In Exp. 1, 20 crossbred steers were assigned randomly to one of four treatment diets consisting of either 0, 2.5, 5.0, or 7.5 x 106 IU of VITD per day for 10 d. Blood samples were obtained daily during this supplementation period and 5 d thereafter (d 11 to 15). Between d 6 and 13, a linear increase (P < .01) in ionized plasma calcium concentrations was observed in steers supplemented with VITD. Compared to unsupplemented steers, serum calcium concentrations of the steers receiving 7.5 x 106 IU of VITD per day were increased 8 to 48%. In Exp. 2, longissimus samples from crossbred steers (n = 118) that were supplemented with either 0 or 5 x 106 IU of VITD per day for 7 d were obtained and aged for 7, 14, or 21 d. Following the initial 7-d postmortem aging period, VITD supplementation lowered (P < .01) WBS (.58 kg) and increased sensory tenderness rating (.6 units) compared to cuts originating from unsupplemented steers. In Exp. 3, 44 steers were supplemented with either 0 or 7.5 x 106 IU of VITD per day for 10 d immediately prior to slaughter. Results indicated that plasma and longissimus calcium concentration were higher (P < .05) for steers that received supplemental VITD. Compared with unsupplemented cuts, VITD supplementation improved WBS of cuts aged for either 7 or 14 d (P = .02 and P = .07, respectively). Sensory panelists rated samples from VITD supplemented steers as more tender than their unsupplemented counterparts. Activation of calpain proteases could be responsible for the observed tenderization due to the supplementation of VITD. (+info)
Tenderness classification of beef: IV. Effect of USDA quality grade on the palatability of "tender" beef longissimus when cooked well done.
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The objective of this experiment was to determine the impact of USDA quality grade on the palatability of "tender" longissimus when cooked well done. Warner-Bratzler shear force was determined on longissimus thoracis steaks aged 3 or 14 d postmortem (cooked to 70 degrees C) from carcasses of 692 steers and heifers. Steaks from 31 carcasses with Modest or Moderate marbling scores (Top Choice) and steaks from 31 carcasses with Slight00 to Slight40 marbling scores (Low Select) were selected for this experiment from carcasses identified as "tender" (shear force < 5.0 kg at 3 d postmortem). Longissimus thoracis steaks with 3 or 14 d of postmortem aging were cooked to 80 degrees C and evaluated by a trained sensory descriptive attribute panel. Top Choice steaks had higher (P < .05) juiciness (5.8 vs 5.3) and beef flavor intensity ratings (4.9 vs 4.6) than Low Select steaks. Aging of steaks for 14, rather than 3, d postmortem improved (P < .05) beef flavor intensity rating (4.8 vs 4.7) but not (P > .05) juiciness rating (5.6 vs 5.5). The interaction (P < .05) of quality grade and aging time for tenderness rating indicated that Top Choice steaks were more tender (P < .05) with 3 d of aging than steaks from Low Select carcasses (6.3 vs 5.8), but steaks from Top Choice and Low Select carcasses had similar (P > .05) tenderness ratings after 14 d of aging (7.0 and 6.8). Compared to palatability of steaks from Low Select carcasses, the palatability of steaks from Top Choice carcasses was less affected by elevated degree of doneness in "tender" longissimus thoracis, especially when steaks were aged for only 3 d. Although differences in sensory traits between Top Choice and Low Select steaks were small, the consumers who cook beef well done may benefit from implementation of tenderness classification in conjunction with USDA quality grade. (+info)
Predicting carcass composition of beef cattle using ultrasound technology.
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We evaluated 20 slaughtered cattle with ultrasound before hide removal to predict fat thickness and ribeye area at the 12th rib for possible use in carcass composition prediction. Carcasses were fabricated into boneless subprimals that were trimmed progressively from 2.54 to 1.27 to .64 cm maximum fat trim levels. Stepwise regression was used to indicate the relative importance of variables in a model designed to estimate the percentage of boneless subprimals from the carcass at different external fat trim levels. Variables included those obtained on the slaughter floor (ultrasound fat thickness and ribeye area; estimated percentage of kidney, pelvic, and heart [KPH] fat; and warm carcass weight) and those obtained from carcasses following 24 h in the chill cooler (actual fat thickness, actual ribeye area, estimated percentage of KPH fat, warm carcass weight, and marbling score). At all different subprimal trim levels, percentage KPH was the first variable to enter the model. In the models using measures taken on the slaughter floor, ultrasound fat thickness was the only other variable to enter the model. Ultrasound fat thickness increased R2 and decreased residual standard deviation (RSD) in models predicting subprimals at 2.54-cm maximum fat trim; however, at 1.27- and .64-cm trim levels, R2 and RSD increased. Models using the same two variables (except actual fat instead of ultrasound) in the cooler were similar to those using data from the slaughter floor. However, as more cooler measurement variables entered the models, R2 increased and RSD decreased, explaining a greater amount of the variation in the equation. Ultrasonic evaluation on the slaughter floor may be of limited application compared with the greater accuracy found in chilled carcass assessment. (+info)
Quinolone-resistant Campylobacter jejuni infections in Minnesota, 1992-1998. Investigation Team.
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BACKGROUND: Increasing resistance to quinolones among campylobacter isolates from humans has been reported in Europe and Asia, but not in the United States. We evaluated resistance to quinolones among campylobacter isolates from Minnesota residents during the period from 1992 through 1998. METHODS: All 4953 campylobacter isolates from humans received by the Minnesota Department of Health were tested for resistance to nalidixic acid. Resistant isolates and selected sensitive isolates were tested for resistance to ciprofloxacin. We conducted a case-comparison study of patients with ciprofloxacin-resistant Campylobacter jejuni isolated during 1996 and 1997. Domestic chicken was evaluated as a potential source of quinolone-resistant campylobacter. RESULTS: The proportion of quinolone-resistant C. jejuni isolates from humans increased from 1.3 percent in 1992 to 10.2 percent in 1998 (P<0.001). During 1996 and 1997, infection with quinolone-resistant C. jejuni was associated with foreign travel and with the use of a quinolone before the collection of stool specimens. However, quinolone use could account for no more than 15 percent of the cases from 1996 through 1998. The number of quinolone-resistant infections that were acquired domestically also increased during the period from 1996 through 1998. Ciprofloxacin-resistant C. jejuni was isolated from 14 percent of 91 domestic chicken products obtained from retail markets in 1997. Molecular subtyping showed an association between resistant C. jejuni strains from chicken products and domestically acquired infections in Minnesota residents. CONCLUSIONS: The increase in quinolone-resistant C. jejuni infections in Minnesota is largely due to infections acquired during foreign travel. However, the number of quinolone-resistant infections acquired domestically has also increased, largely because of the acquisition of resistant strains from poultry. The use of fluoroquinolones in poultry, which began in the United States in 1995, has created a reservoir of resistant C. jejuni. (+info)
The fate of folate polyglutamates in meat during storage and processing.
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The rate of hydrolysis of chicken liver folate polyglutamates, by endogenous liver conjugases, under various conditions of storage, heat, and tissue disruption, were investigated. The procedure used was to allow a radioactive tracer dose of the vitamin to equilibrate into the folate polyglutamyl pool. After various storage periods and treatments the polyglutamyl state of the folate present was examined by analytical techniques based on oxidative degradation of native folate polyglutamates to the corresponding p-aminobenzoylpolyglutamate followed by chromatographic separation on DEAE cellulose anion exchange resin. Identification of folate polyglutamates present was made by simultaneous elution of known p-aminobenzoylpolyglutamate markers. In an intact tissue sample only slight degradation was found after 48 hr at 4 C; complete degradation of folate polyglutamates taking 120 hr. Samples of homogenized tissue show complete degradation to folate monoglutamates and a small amount of diglutamate after 48 hr storage. Superimposed on the above is the consideration that if at any time prior to or during storage the liver is heated to greater than 100 C irreversible inactivation of the endogenous conjugases takes place and the folate polyglutamate pattern is stabilized. It was also demonstrated that during two different heating procedures no extra deconjugation occurred. (+info)
Foods contributing to absolute intake and variance in intake of fat, fatty acids and cholesterol in middle-aged Japanese.
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On the basis of 351 one-day weighed diet records, we selected foods/recipes contributing to nutrients of interest for a data-based food frequency questionnaire by contribution analysis and multiple regression analysis. Total fat was largely of animal and vegetable origin, irrespective of analytic methods. Saturated fatty acid was mostly from animal and vegetable sources according to contribution analysis, and that of animal origin was the main contributor by multiple regression analysis. Mono-unsaturated fatty acid was substantially supplied by animal and vegetable products by either analytic method. Poly-unsaturated fatty acid, n-6 poly-unsaturated fatty acid and linoleic acid were found to be of vegetable origin and chicken egg according to contribution analysis; while vegetable oil and mayonnaise were the major contributors to variance in intake. Arachidonic acid was, however, mostly provided by animal sources including chicken egg and fish, irrespective of analytic methods. N-3 poly-unsaturated fatty acids and alpha-linolenic acid were of vegetable and marine origin. Eicosapentaenoic and docosahexaenoic acids were particularly from marine products, irrespective of analytic methods, except for chicken egg in docosahexaenoic acid by contribution analysis. Cholesterol was of animal and marine origin by either analytic method. Thus, foods contributing to absolute intake and variance in intake of fat, fatty acids and cholesterol differed considerably. (+info)
Fish and mammals in the economy of an ancient Peruvian kingdom.
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Fish and mammal bones from the coastal site of Cerro Azul, Peru shed light on economic specialization just before the Inca conquest of A. D. 1470. The site devoted itself to procuring anchovies and sardines in quantity for shipment to agricultural communities. These small fish were dried, stored, and eventually transported inland via caravans of pack llamas. Cerro Azul itself did not raise llamas but obtained charqui (or dried meat) as well as occasional whole adult animals from the caravans. Guinea pigs were locally raised. Some 20 species of larger fish were caught by using nets; the more prestigious varieties of these show up mainly in residential compounds occupied by elite families. (+info)