Tenderness and sensory attributes of the longissimus lumborum muscles with different quality grades from Chinese fattened yellow crossbred steers.

The objectives were to investigate intramuscular fat (IMF) content,Warner­Bratzler shear force(WBSF) and sensory attributes of Chinese fattened yellow crossbred steer beef with different quality grades, and to determine the relationship between WBSF and Chinese consumers' sensory tender. WBSF of grades A1 to A5 decreased from 50.6 N to 33.1 N with IMF % increased from4.26 to 24.55 (P b 0.05). Consumer panelists showed more likeability grades A4 and A5 with no difference between them. Grades A2 and A3 were slightly preferred (P b 0.05). Grade A1 was undesirable. A regression relationship between WBSF and sensory tender was found, which indicated that consumers disliked beef when WBSF N55.43 N and preferred those with WBSF b41.4 N. The range of 41.4 N to 55.43 N was intermediate. Hence, WBSF N55.43 & b41.4 N allow classification of tough and tender for beef tenderness for Chinese consumers, and grade A4 was recommended as suitable top grade.

Collective sensing and collective responses in quorum-sensing bacteria.

Bacteria often face fluctuating environments, and in response many species have evolved complex decision-making mechanisms to match their behaviour to the prevailing conditions. Some environmental cues provide direct and reliable information (such as nutrient concentrations) and can be responded to individually. Other environmental parameters are harder to infer and require a collective mechanism of sensing. In addition, some environmental challenges are best faced by a group of cells rather than an individual. In this review, we discuss how bacteria sense and overcome environmental challenges as a group using collective mechanisms of sensing, known as 'quorum sensing' (QS). QS is characterized by the release and detection of small molecules, potentially allowing individuals to infer environmental parameters such as density and mass transfer. While a great deal of the molecular mechanisms of QS have been described, there is still controversy over its functional role. We discuss what QS senses and how, what it controls and why, and how social dilemmas shape its evolution. Finally, there is a growing focus on the use of QS inhibitors as antibacterial chemotherapy. We discuss the claim that such a strategy could overcome the evolution of resistance. By linking existing theoretical approaches to data, we hope this review will spur greater collaboration between experimental and theoretical researchers.

Importance of grass-legume choices on cattle grazing behavior, performance, and meat characteristics.

We determined if tall fescue in a mixture with either tannin-containing sainfoin or saponin-containing alfalfa affected cattle foraging behavior, performance, meat quality, and consumer acceptance of meat. Foraging behavior, BW, and pasture biomass before and after grazing were monitored when cattle strip-grazed 3 replications of 2 treatments from May through September 2010 (12 calves/replication) and from June through September 2012 (8 calves/replication). Animals were allowed a choice between tall fescue and sainfoin (SAN) or tall fescue and alfalfa (ALF) growing in strips (fescue, legume, and fescue-legume mixture). Incidence of use (scan samples) of legumes increased from the beginning to the end of the trials (P < 0.05), suggesting that cattle learned to mix legumes with tall fescue. Scan samples and assessments of pasture biomass removal revealed greater use of sainfoin than alfalfa when both legumes were abundant in the spring (P < 0.05); that pattern reversed toward the end of the growing season (P < 0.05) as the abundance of sainfoin declined more than that of alfalfa. Intake of forage per kilogram of gain was greater for SAN than for ALF in 2010 (P = 0.0003) and showed a tendency to be greater for SAN than ALF in 2012 (P = 0.19). There were no differences in ADG between SAN and ALF in either year (1 kg/d; P > 0.05). No incidences of bloat were detected. When cattle (3 calves/treatment in 2010 and 8 calves/treatment in 2012) were slaughtered in September to assess meat quality and consumer acceptance, carcasses were lean (4% to 6% fat content of the longissimus muscle), but compared with ALF, SAN had higher marbling scores, quality grades (Select versus Standard), and back fat thicknesses (P < 0.05) in 2012. Steaks from cattle finished on SAN were redder in color than steaks from cattle finished on ALF (P < 0.05; 2012). Meat samples from SAN and ALF showed some differences in unsaturated fatty acid profiles and volatiles concentrations (P < 0.05), but consumer acceptance did not differ between SAN and ALF (P > 0.05). Thus, cattle incorporated a lower-quality grass into their diets even when legumes were available ad libitum during most grazing trials. Choices between tall fescue and legumes differing in the type of secondary compound (tannins vs. saponins) and bloating potential influenced patterns of forage use by cattle and led to differences in meat quality.

The quality of meat from sheep treated with tannin- and saponin-based remedies as a natural strategy for parasite control.

Lambs were assigned to four groups of seven and treated as follows for 12 days: control group (BP) was fed beet pulp; group T (tannin remedy) received the BP diet including 80 g/kg of quebracho extract; group S (saponin remedy) received the BP diet including 15 g/kg of quillaja extract; and group C had a free choice between T and S remedies. Lipid oxidation was lower in meat from S lambs compared to T lambs (P<0.05). Among the volatile compounds, lactate was lower in meat from S lambs compared to T animals (P=0.05). Metabolomic analysis showed that the T treatment increased ribose, fructose, glucose and sorbitol concentration in meat (P<0.05), while cholesterol was decreased by S and C treatments. The T treatment increased the concentration of C14:1 cis-9 (P<0.05). These findings indicate that treatments for parasite control containing tannins and saponins do not detrimentally affect sheep meat quality.

Evaluation of high humidity and wet marinade methods for pasteurization of jerky.

The USDA FSIS meat and poultry jerky compliance guidelines recommend a high humidity or liquid immersion pasteurization step before drying. The objective of this study was to evaluate the effects of high humidity (>90%) or wet marinade pasteurization on jerky characteristics (water activity, moisture/protein ratio, total aerobic plate count [TAC]) and sensory properties. Jerky pasteurized by nonmarinade method A (76.6 degrees C dry bulb, 54.4 degrees C oven wet bulb temperature for 1 h) had highest sensory scores for spice intensity and interior cured color (redness), and generally lower TACs than jerky from marinade pasteurization methods. Jerky pasteurized by method B (54 degrees C for 121 min in marinade) had higher TACs than other methods. Approximately 2-log reduction in TAC was observed using marinade pasteurization in the smokehouse to internal temperature of 60 degrees for 12 min (method C), or in hot marinade to internal temperature of 70 degrees C before drying (method D), but jerky was less spicy and somewhat darker than jerky from method A. Extruded jerky (1.5-cm thickness) was similar to intact jerky for spice flavor intensity and interior redness, but required longer drying time to reach the target Aw of 0.85. Marinade pasteurization by methods C or D was feasible, and may be a preferred alternative for some processors, since monitoring of oven humidity during pasteurization is not necessary.

Antioxidant mechanism of milk mineral-high-affinity iron binding.

Milk mineral (MM), a by-product of whey processing, is an effective antioxidant in meat systems, but the antioxidant mechanism has not been established. MM has been postulated to chelate iron and prevent iron-catalysis of lipid oxidation. The objective of this research was to examine this putative mechanism. MM was compared to sodium tripolyphosphate (STPP), calcium phosphate monobasic (CPM), and calcium pyrophosphate (CPP) to determine iron-binding capacity, sample solubility, and eluate soluble phosphorus after treating samples with a ferrous chloride standard. Scanning electron microscopy with energy-dispersive X-ray analysis was used to localize minerals on iron-treated MM particle surfaces. Histochemical staining for calcium was performed on raw and cooked ground beef samples with added MM. MM bound more iron per gram (P < 0.05) than the other compounds, and was much less soluble (P < 0.05) than either STPP or CPM. Mineral localization showed an even distribution of calcium, phosphorus, oxygen, and iron across the MM particle surface, directly demonstrating iron binding to MM particles. Unlike other common chelating agents, such as STPP and citrate, histochemical staining demonstrated that MM remained insoluble in ground beef, even after cooking. The ability of MM to bind iron and remain insoluble may enhance its antioxidant effect by removing iron ions from solution. However, MM particles must be small and well distributed in order to adequately bind iron throughout the food system.

A nurse- and pharmacist-led treatment advice clinic for patients attending an HIV outpatient clinic.

AIM: This paper is a report of a study to map care pathways, examine the approach of different treatment advisors and explore the acceptability of a nurse- and pharmacist-led treatment advice clinic in order to aid decision-making for the future development and evaluation of the clinic. BACKGROUND: High levels of adherence to antiretroviral drugs are a prerequisite for a successful and durable virological and immunological response to HIV. Treatment guidelines acknowledge that adherence is a process, not a single event, and that adherence support must be integrated into clinical follow-up for all patients receiving these drugs. METHOD: Data were collected between September 2004 and January 2005 through 17 consultation observations and 10 patient interviews in a specialist treatment advice clinic located within a central London HIV outpatient clinic providing care for over 2200 patients, of whom more than 1300 are taking highly active antiretroviral therapy. FINDINGS: The nurses and pharmacist had similar consultation approaches, although follow-up care varied in extent. Benefits of the clinic approach included permitting patients to observe real tablets, tailoring regimens to lifestyles and telephone follow-up. These factors, particularly telephone support, were perceived by patients to assist with adherence. CONCLUSION: The role of telephone support, perceived to assist with initial adherence, requires further investigation. Future work is also needed to explore the health economics of this approach and to determine the actual impact of the clinic on clinical and adherence outcomes.

P-glycoprotein and MRP1 expression and reduced ritonavir and saquinavir accumulation in HIV-infected individuals.

OBJECTIVES: Efflux transporters may play a role in lowering intracellular drug concentrations. As the HIV protease inhibitors are substrates for the efflux transporters P-glycoprotein and MRP, we wished to investigate whether differences in expression of these transporters on human lymphocytes correlated with intracellular concentrations of ritonavir and saquinavir. PATIENTS AND METHODS: Drug efflux transporter expression (P-glycoprotein and MRP1) on peripheral blood mononuclear cells isolated from HIV-positive patients was investigated using flow cytometry. In addition, plasma and intracellular ritonavir and saquinavir concentrations were measured by HPLC/mass spectrometry. The ratio of intracellular:plasma drug concentration was used to quantify intracellular drug accumulation. RESULTS: Patients with lower MRP1 expression (

Consumer preferences for beef color and packaging did not affect eating satisfaction.

We investigated whether consumer preferences for beef colors (red, purple, and brown) or for beef packaging systems (modified atmosphere, MAP; vacuum skin pack, VSP; or overwrap with polyvinyl chloride, PVC) influenced taste scores of beef steaks and patties. To test beef color effects, boneless beef top loin steaks (choice) and ground beef patties (20% fat) were packaged in different atmospheres to promote development of red, purple, and brown color. To test effects of package type, steaks and patties were pre-treated with carbon monoxide in MAP to promote development of red color, and some meat was repackaged using VSP or PVC overwrap. The differently colored and packaged meats were separately displayed for members of four consumer panels who evaluated appearance and indicated their likelihood to purchase similar meat. Next, the panelists tasted meat samples from what they had been told were the packaging treatments just observed. However, the meat samples actually served were from a single untreated steak or patty. Thus, any difference in taste scores should reflect expectations established during the visual evaluation. The same ballot and sample coding were used for both the visual and taste evaluations. Color and packaging influenced (P<0.001) appearance scores and likelihood to purchase. Appearance scores were rated red>purple >brown and PVC >VSP>MAP. Appearance scores and likelihood to purchase were correlated (r=0.9). However, color or packaging did not affect (P>0.5) taste scores. Thus, consumer preferences for beef color and packaging influenced likelihood to purchase, but did not bias eating satisfaction.

Evaluation of carbon monoxide treatment in modified atmosphere packaging or vacuum packaging to increase color stability of fresh beef.

Our goal was to obtain > 21 days red color stability for carbon monoxide (CO)-treated beef steaks in vacuum packaging (VP). In preliminary tests, pretreatment for 24 h in a 5% CO modified atmosphere package (MAP) was needed to maintain redness after re-packaging in VP. Pressure pretreatment with 5% CO for 2 h developed redness, but was impractical for large-scale application. Color stability and microbial load were then compared after treatment of steaks in 5% CO-MAP for 24 h, then VP; 100% CO-MAP for 1 h, then VP; steaks and ground beef in 0.5% CO-MAP; and steaks and ground beef in polyvinyl chloride (PVC) wrap. Steaks remained red for 5, 6, 8 and <1-week storage at 2°C, respectively. Steaks microbial load exceeded spoilage levels (>10(6)cfu/cm(2)) at 5, 6, 7 and <2-weeks, respectively. Thus, extended color stability in VP was achieved by pretreatment with 5% CO for 24 h or 100% CO for 1 h.

Minimum sodium nitrite levels for pinking of various cooked meats as related to use of direct or indirect-dried soy isolates in poultry rolls.

The relationship between sodium nitrite level and pinking was investigated in cooked meats, as measured by panel color score, acetone extraction of NO-hemochrome, and instrumental redness values. Beef was less susceptible than poultry breast meat to nitrite-induced pinking. Minimum sodium nitrite level for pinking was 14, 4, 2, and 1 ppm for beef round, pork shoulder, turkey breast, and chicken breast, respectively. By regression analysis, minimum ppm nitrite for pinking=0.092 (ppm total pigment)+0.53 (R(2)=0.99). High levels of nitrate (>250 ppm as sodium nitrate) and nitrite (>45 ppm as sodium nitrite) were found in direct-dried (DD) soy isolates. Chicken breast rolls formulated with >2% DD soy were pink, but control rolls with 156 ppm sodium nitrate were not pink. Thus, it was concluded that nitrite was the primary pinking agent in DD soy. Indirect-dried (ID) soy isolates contained <11 ppm sodium nitrite, which was insufficient for pinking in poultry rolls.

A comparison of carnosine and ascorbic acid on color and lipid stability in a ground beef pattie model system.

Ascorbic acid (0.1%) significantly inhibited metmyoglobin formation on the surface of ground beef but not in the bulk of the product where oxygen tension was lower. Carnosine (1.0%), however, significantly inhibited metmyoglobin formation and brown color development throughout the product. The combinations of carnosine and ascorbic acid were also very effective on inhibition of metmyoglobin formation and brown color development. Carnosine increased meat pH, cook yield and salt-soluble protein, but ascorbic acid had no effect on cook yield, and decreased meat pH and salt-soluble protein. Carnosine was more effective on inhibition of lipid peroxidation than ascorbic acid. Carnosine inhibited copper(II)-catalyzed ascorbate oxidation in a dose-dependent manner in model systems. Carnosine in conjunction with ascorbic acid may be useful as a meat additive for increasing shelf-life as well as stabilizing color of meat products.

Effect of sodium phytate, sodium pyrophosphate and sodium tripolyphosphate on physico-chemical characteristics of restructured beef.

The effects of 0.5% sodium phytate (SPT), sodium pyrophosphate (SPP), and sodium tripolyphosphate (STPP), along with 1% NaCl, on physico-chemical properties of restructured raw and cooked beef were evaluated. In raw beef stored for 1 day at 4 ° C, the SPT, SPP, and STPP increased pH and salt-soluble protein level and decreased %MetMb and thiobarbituric acid reactive substances (TBARS), compared to the control with salt alone (p < 0.05). In cooked beef, SPT, SPP, and STPP increased bind strength, cook yield, moisture level, and pH, and decreased TBARS (p < 0.05). SPP and STPP increased orthophosphate in both raw and cooked beef (p < 0.05), compared to the SPT and control. SPT, SPP, and STPP decreased the Hunter color L and b values and increased a value in raw beef (p < 0.05) but had no effect on the Hunter color values in cooked beef. The binding value of SPP and STPP were similar over time, and the time to reach maximum binding strength was 10s longer than SPT and 25s longer than the control. These results indicate that SPT compares favorably with traditional phosphates for bind strength and cooked yield, but SPT was slightly more effective than other phosphates for reduction of TBARS 1 day after cooking.

Sodium hydroxide and sodium tripolyphosphate effects on bind strength and sensory characteristics of restructured beef rolls.

Restructured beef rolls formulated with 1% NaCl (controls) or with 1% NaCl plus 0.07% NaOH or 0.375% sodium tripolyphosphate (STPP) had different (p < 0.05) relative bind strength and cooked yield, as follows: STPP > NaOH > controls. Percent cooked yield was inversely affected (p < 0.05) by added water level (5 > 10 > 20%). Bind values were lower (p < 0.05) in rolls with 20% added water. NaOH and STPP rolls had higher pH (p < 0.05) than controls (6.28, 6.22, and 6.07, respectively). Panel cohesiveness, juiciness, and acceptability scores were also generally higher (p < 0.05) for NaOH and STPP rolls, compared to controls. There was a high correlation (0.93) between panel cohesiveness scores and instrumental bind values. At 20% added water, STPP rolls were preferred, but at 10% added water, STPP and NaOH rolls were similar in overall acceptability. Thus, if added water level is not too high, NaOH alone or perhaps with other binding agents may be an alternative to phosphates in cooked beef rolls.

Effects of time on feed and post-mortem aging on palatability and lipid composition of crossbred Wagyu beef.

Twenty-seven Wagyu-sired steers were fed for 90 (14 steers) or 170 (13 steers) days to study the effects of time on feed on palatability and fatty acid composition, and the effects of post-mortem aging time (2, 4 or 10 days) on palatability. Hot carcass weight, fat thickness, longissimus dorsi muscle area, yield grade, estimated kidney, pelvic and heart fat and maturity score were increased (p < 0.05) by an additional 80 days on the high concentrate feed, but marbling was not changed (p > 0.05). Feeding the high concentrate diet for 170 days increased Warner-Bratzler shear force values (p < 0.05) and tended to decrease tenderness (p > 0.05), flavor intensity and connective tissue scores. For the 90 day feeding group, 4 days of aging improved connective tissue score (p < 0.05) and tended to increase (p > 0.05) tenderness scores and decrease shear force, compared with 2 days of aging. For the 170 day feeding group, 10 days of aging improved (p < 0.05) shear force and all sensory attributes except flavor intensity, compared to 2 days of aging. An additional 80 days on feed decreased (p < 0.05) stearic acid and total saturated fatty acids (SFA) and generally increased (p < 0.05) monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), MUFA:SFA, and PUFA:SFA in subcutaneous fat and longissimus dorsi muscle. The cholesterol content of fat and muscle increased (p < 0.05) as time on feed increased. Ninety days on a high concentrate diet was adequate for yearling crossbred Wagyu steers to produce highly acceptable carcasses. The additional 80 days on feed produced little or no overall benefit and the steers became overfinished and less tender. Ten days post-mortem aging improved (p < 0.05) all palatability attributes except flavor intensity.

Inactivation of clostridial ferredoxin and pyruvate-ferredoxin oxidoreductase by sodium nitrite.

Clostridial ferredoxin and pyruvate-ferredoxin oxidoreductase activity was investigated after in vitro or in vivo treatment with sodium nitrite. In vitro treatment of commercially available Clostridium pasteurianum ferredoxin with sodium nitrite inhibited ferredoxin activity. Inhibition of ferredoxin activity increased with increasing levels of sodium nitrite. Ferredoxin was isolated from normal C. pasteurianum and Clostridium botulinum cultures and from cultures incubated with 1,000 micrograms of sodium nitrite per ml for 45 min. The activity of in vivo nitrite-treated ferredoxin was decreased compared with that of control ferredoxin. Pyruvate-ferredoxin oxidoreductase isolated from C. botulinum cultures incubated with 1,000 micrograms of sodium nitrite per ml showed less activity than did control oxidoreductase. It is concluded that the antibotulinal activity of nitrite is due at least in part to inactivation of ferredoxin and pyruvate-ferredoxin oxidoreductase.

Nitrite inhibition of Clostridium botulinum: electron spin resonance detection of iron-nitric oxide complexes.

Vegetative cells of Clostridium botulinum were shown to contain iron-sulfur proteins that react with added nitrite to form iron-nitric oxide complexes, with resultant destruction of the iron-sulfur cluster. Inactivation of iron-sulfur enzymes (especially ferredoxin) by binding of nitric oxide would almost certainly inhibit growth, and thus is probably the mechanism of botulinal inhibition by nitrite in foods.

Bioavailability to anemic rats of iron from fresh, cooked or nitrosylated hemoglobin and myoglobin.

Bioavailabilities of heme iron prepared from lyophilized, fresh, cooked, nitrosylated hemoglobin and purified myoglobin in semipurified diets were investigated in two experiments. In experiment 1, the bioavailabilities of porcine and bovine hemoglobins were about one-third that for ferrous sulfate regardless of hemoglobin treatments. The efficiency of hemoglobin regeneration by anemic rats fed nitrosylated pork hemoglobin was significantly depressed compared with that by those fed unnitrosylated products. Cooking did not affect the availability of the heme iron, whereas washing tended to increase it. In experiment 2, the hemoglobin regeneration efficiency of the purified myoglobin diet was lower than reported by others for meat diets, and was even lower than that of the purified hemoglobin diet. The respective efficiency values for the basal, basal + FeSO4, hemoglobin, and myoglobin diets (experiment 2) were 0.073, 0.581, 0.199, and 0.125. The efficiencies of converting hemoglobin and ferrous sulfate iron into hemoglobin by the anemic rats were very similar to reported absorption values for these iron sources by iron-deficient human subjects.

Effects of N-nitrosopyrrolidine, nitrite and pyrrolidine on tumour development in mice as related to ingestion of cured meat.

The incidence of tumours in mice fed a standard chow diet and given either N-nitrosopyrrolidine (NPyr), nitrite (NO(2)) or nitrite plus pyrrolidine (NO(2) + Pyr) in the drinking water for 12 months at 100mg, 1 g and 1 g plus 100mg/litre, respectively, was compared with that for a control group (C) receiving no additives. Differences between groups in weight gain and feed consumption were not significant. Group 3 (NO(2)) drank less water (P < 0·05) than those in groups 1 (C) and 2 (NPyr). Water intake of mice in group 4 (NO(2) + Pyr) did not differ from that of any of the other three groups. Survival rates were: 94% (C), 80% (NPyr), 92% (NO(2)) and 83% (NO(2) + Pyr); but the differences were not statistically significant. Gross examination upon autopsy revealed that the incidence of all tumours in group 2 (NPyr) was 10- to 20-fold higher than that in any other group. Histological examination confirmed that NPyr induced more (P < 0.05) malignant tumours in liver and lungs with any other treatment; otherwise there were no significant differences. Results indicated that NO(2) + Pyr (nitrite plus a secondary amine) did not increase the frequency of carcinogenic tumours in mice.

Relationship of mitochondria and sarcoplasmic reticulum to cold shortening.

Sarcoplasmic reticulum and mitochondria preparations from beef and rabbit muscle were shown to bind and release appreciable quantities of Ca(++). Differences between rabbit and beef muscle in Ca(++) binding and release by SR and mitochondrial preparations were not sufficient to account for the massive shortening in chilled beef as compared to little or no shortening in chilled rabbit muscle. Results substantiate the theory of Buege & Marsh (1975) that cold shortening is related to differences in mitochondrial concentration in red and white muscle rather than to differences in the Ca(++)-accumulating ability of SR. In order to explain the reversibility of cold shortening upon rewarming pre-rigor red muscle, a role for both SR and mitochondria is postulated and discussed.