Quantifying the rate of pH and temperature decline in lamb carcasses using medium voltage electrical stimulation in an Australian abattoir

2006 ◽  
Vol 46 (7) ◽  
pp. 869 ◽  
Author(s):  
K. L. Pearce ◽  
D. L. Hopkins ◽  
E. Toohey ◽  
D. W. Pethick ◽  
I. Richards
Keyword(s):  
Electrical Stimulation ◽  
Pulse Width ◽  
Eating Quality ◽  
Medium Voltage ◽  
Initial Ph ◽  
Australian Sheep ◽  
Temperature Window ◽  
Late Application ◽  
Rate Of Decline ◽  
The Individual

The current study evaluated the effectiveness of a medium voltage post-dressing electrical stimulation unit at different current and pulse width settings on pH decline. The objective was to optimise these settings to ensure that a high proportion of carcasses would reach pH 6.0 when the carcass was between 18–25°C according to the guidelines set by the Australian Sheep Meat Eating Quality (SMEQ) program. In the first experiment, 3 different current (400, 700 and 1000 mA) and pulse width (1, 2.5 and 5 ms) settings plus a control (0 mA and 0 ms) were applied to carcasses for 34 s at a frequency of 15 Hz with 7 sheep per treatment over 3 consignments (n = 210 carcasses). The pH–temperature decline was evaluated for all carcasses. Based on the SMEQ guidelines, 43% of stimulated carcasses reached a pH of 6.0 between a carcass temperature of 18–25°C, compared with 14% of unstimulated controls. Furthermore, 21% of carcasses reached a pH of 6.0 before the carcass temperature reached 25°C and 36% did not reach a pH of 6.0 by the time the carcass was 18°C. Alternatively, under the Meat Standards Australia (MSA) pH–temperature guidelines, carcasses should reach pH 6.0 between 12 and 35°C; 87% of stimulated carcasses reached a pH of 6.0 between 12–35°C, compared with 39% of unstimulated controls. One percent of carcasses reached a pH of 6.0 before the carcass temperature reached 35°C and 12% did not reach a pH of 6.0 by a carcass temperature by the time the carcass was 12°C. The abattoir in this study had a very fast chilling regime which resulted in carcasses reaching pH 6.0 at low temperatures and accounted for the low number of carcasses reaching a pH of 6.0 between 18–25°C. There was no effect of different current and pulse widths on the rate of decline, temperature at pH 6.0 or initial pH, which was attributed to the late application of electrical stimulation postmortem when muscle contraction is dependant on direct muscle stimulation. The combination of 2.5 ms and 1000 mA was the best performing treatment with respect to both SMEQ and MSA guidelines and the number of carcasses reaching the pH–temperature window. This treatment had the highest percentage of carcasses reaching the SMEQ window (60%) and MSA window (97%). Furthermore, it resulted in the lowest number of carcasses not reaching pH 6.0 by a carcass temperature of either 12 or 18°C, making it the most suitable to an abattoir with a fast chilling regime. Modulation and frequency manipulation of the segmented electrodes were assessed with the frequency manipulation resulting in the greatest stimulation response. Further work is needed to understand the effect of manipulating the frequency on the system overall or of the individual modules as well as changing the stimulation time.

Case studies demonstrating the benefits on pH and temperature decline of optimising medium-voltage electrical stimulation of lamb carcasses

2010 ◽  
Vol 50 (12) ◽  
pp. 1107 ◽  
Author(s):  
K. L. Pearce ◽  
R. van de Ven ◽  
C. Mudford ◽  
R. D. Warner ◽  
J. Hocking-Edwards ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Current Approach ◽  
Random Regression ◽  
Eating Quality ◽  
Medium Voltage ◽  
Sheep Meat ◽  
Random Regression Model ◽  
Optimum Ph ◽  
Temperature Window ◽  
Stimulation System

The efficacies of electrical stimulation practices at Australian abattoirs that process significant proportions of Australian lamb and sheep meat were assessed. Several abattoirs used medium-voltage electrical stimulation system (MVS) units suboptimally and many carcasses at these abattoirs exhibited a poor rate of pH decline and, consequently, a low proportion of carcasses attained pH 6 at a carcass temperature of 18−35°C, according to Sheep Meat Eating Quality pH–temperature guidelines as adopted by Meat Standards Australia. In the present communication, we describe the causes of suboptimal results with electrical stimulation and discuss procedures for optimising the stimulation dose delivered by MVS units. Carcass pH responses to various levels of current and pulse width were assessed to determine the best MVS settings for individual abattoirs. The MVS units at the abattoirs involved in the present study have now been programmed for optimal efficacy and carcass quality will be monitored on an ongoing basis. Evaluation of methods for assessing the proportion of carcasses that fall within the optimum pH–temperature window showed that a random regression model is more accurate than the current approach.

New electrical stimulation technologies for sheep carcasses New electrical stimulation technologies for sheep carcasses

2005 ◽  
Vol 45 (5) ◽  
pp. 575 ◽  
Author(s):  
F. D. Shaw ◽  
S. R. Baud ◽  
I. Richards ◽  
D. W. Pethick ◽  
P. J. Walker ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
High Voltage ◽  
Consumer Satisfaction ◽  
Electrode System ◽  
Constant Current ◽  
Eating Quality ◽  
Meat Eating ◽  
Medium Voltage ◽  
Sheep Meat ◽  
Maximum Voltage

High voltage electrical stimulation applied to the lamb carcass at the end of the dressing procedure often leads to an improvement in overall product quality by reducing the incidence of toughness. It would be advantageous if the same results could be consistently achieved with the use of lower, safer, voltages — medium voltage electrical stimulation. Experiments were conducted to determine the effect of medium voltage electrical stimulation applied to wool-on carcasses on meat quality as assessed using the Sheep Meat Eating Quality protocols. A further experiment examined the interaction of electrical stimulation and meat aging time on the consumer acceptance of lamb meat. In the first experiment, 3 treatments: control (non-stimulated), medium voltage electrical stimulation (applied to the wool-on carcass) and high voltage electrical stimulation (applied at the completion of dressing) were examined. Samples of the loin (LTL) and rump (GM) muscles were evaluated by consumers using Sheep Meat Eating Quality protocols. For both muscles, the consumers gave higher scores for tenderness, juiciness, flavour and overall acceptability to the stimulated product (P<0.001). There were no statistically significant differences between the 2 stimulation treatments. The second experiment was conducted at a commercial lamb-processing abattoir that had installed a prototype automated electrode system designed to work at chain speed. Lambs received either no stimulation (control), low current medium voltage electrical stimulation (constant current 300 mA peak, 15 Hz, maximum voltage 550 V peak) or high current medium voltage electrical stimulation (constant current 600 mA peak, 15 Hz, maximum voltage 550 V peak) immediately after sticking. Electrical stimulation improved both the objective and sensory (Sheep Meat Eating Quality) eating quality attributes of lamb loin muscle when assessed following 2 days of ageing. When expressed according to consumer satisfaction rating, 30, 37 and 70% of the loins receiving low, high or no electrical stimulation, respectively, were rated as unsatisfactory at 2 days of ageing. At 4 days of ageing no loins from carcasses in the low stimulation treatment were rated by consumers to be unsatisfactory (P<0.05) compared with either non-stimulated (40%) or high-stimulated loins (35%). With respect to the effects of aging meat, electrical stimulation improved the consumer score at 2 days post-stunning by 8.9 and 4.7 points for tenderness and overall liking, respectively. Further linear improvements due to aging were similar for both electrical stimulation and unstimulated products. Under conditions of no electrical stimulation used in this experiment, 10 days aging results in tenderness and overall liking scores greater than 60 and with ES similar scores are achieved in 5 days. Consumer scores over 60 greatly reduce the chance of meat being classified as unsatisfactory.

Validating the benefits of a medium voltage electrical stimulation unit at an abattoir in Western Australia

2008 ◽  
Vol 48 (7) ◽  
pp. 898 ◽  
Author(s):  
R. H. Jacob ◽  
K. L. Pearce ◽  
N. Smith
Keyword(s):  
Electrical Stimulation ◽  
Western Australia ◽  
Shear Force ◽  
Sarcomere Length ◽  
Quality Parameters ◽  
Eating Quality ◽  
Colour Stability ◽  
Visual Appearance ◽  
Medium Voltage ◽  
Optimal Setting

Two experiments were done following installation of a new generation medium voltage electrical stimulation unit at a commercial lamb abattoir in Western Australia. The first experiment was designed to optimise settings in relation to rate of pH decline post mortem. The second experiment was designed to investigate the eating quality and visual appearance effects of the optimal setting. In the first experiment, nine different settings were compared with a control using 60 lamb carcasses from each of 10 different consignments. The rate of pH × temperature decline was optimal with a pulse width of 2.5 ms and a current of 1.2 A. In the second experiment, 80 lamb carcasses consisting of four carcasses from each of 20 consignments were examined for various eating quality parameters including sarcomere length, shear force, bloom colour and colour stability. Two of the lambs from each consignment were stimulated and two were not stimulated. Stimulation improved compliance with the Sheep Meat Eating Quality (SMEQ) pH × temperature ‘window’ for domestic and frozen product but not for long ship product. Colour was improved by electrical stimulation without changing colour stability. There was a small effect on sarcomere length and no effect of stimulation on shear force measured at day 1 and day 10 after slaughter.

Acute exercise stress and electrical stimulation influence the consumer perception of sheep meat eating quality and objective quality traits

2005 ◽  
Vol 45 (5) ◽  
pp. 553 ◽  
Author(s):  
R. D. Warner ◽  
D. M. Ferguson ◽  
M. B. McDonagh ◽  
H. A. Channon ◽  
J. J. Cottrell ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Acute Exercise ◽  
Low Voltage ◽  
Gluteus Medius ◽  
Lower Surface ◽  
Exercise Stress ◽  
Eating Quality ◽  
General Exercise ◽  
Initial Ph ◽  
Negative Effect

The effects of acute exercise stress and electrical stimulation on lamb eating quality and objective measurements of quality were evaluated on the Longissimus thoracis et lumborum (LTL) and the Gluteus medius (GM) muscles. Meat quality attributes were also assessed on the LTL, Semimembranosus (SM) and the Semispinalis capitis (SC) muscles. Forty-eight Poll Dorset × Border Leicester–Merino ewes of about 6 months old were randomly allocated to treatments in a 2 × 2 factorial design, with the respective factors being exercise (Ex, 0 v. 15 min) and post-slaughter low voltage electrical stimulation (control v. ES). In general, exercise reduced the rate of pH fall and increased the ultimate pH of all 3 muscles (P<0.05). This effect was more pronounced in the SM than in the LTL and SC. Exercised LTL and SM muscles also had lower surface lightness (L*) values and higher muscle total water content, indicating an increased incidence of dark cutting meat. Exercised LTL steaks were rated higher for tenderness and juiciness by the taste panelists and had lower Warner-Bratzler shear force values, as is often observed with high ultimate pH meat. Electrical stimulation reduced initial pH (pH0.5) values, but resulted in a slower rate of pH fall in the LTL and SM thereafter. Electrical stimulation resulted in an elevation of temperature at rigor in the SM by 10°C (15 v. 25°C) and in the LTL by 3.1°C (7.4 v. 10.5°C). While no effect of electrical stimulation was observed with instrumental analysis, electrical stimulation reduced sensory tenderness scores and overall liking for the GM, and tended to reduce flavour and juiciness of both the GM and LTL. In conclusion, acute exercise pre-slaughter improved eating quality, but caused dark cutting meat. The negative effect of low voltage stimulation on the eating quality of the GM was probably due to a high rigor temperature and associated heat toughening.

scholarly journals The Proposal of a New Tool for Condition Assessment of Medium Voltage Power Cable Lines

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4116
Author(s):  
Krzysztof Siodla ◽  
Aleksandra Rakowska ◽  
Slawomir Noske
Keyword(s):  
Research Work ◽  
Technical Condition ◽  
Power Cable ◽  
Investment Planning ◽  
Medium Voltage ◽  
Cable Network ◽  
Rate Analysis ◽  
Cable Lines ◽  
The Individual ◽  
Service Data

A medium voltage (MV) cable network is a substantial component of the distribution network. Present management of this grid segment is mainly based on the failure rate analysis, i.e., a rise in the number and kind of faults on the actual line means that its technical condition is getting worse. The efficiency of the power system is low and additional costs of repair works, supply interruption, difficulties in the investment planning and operation and maintenance works are necessary. The aim of the R&D works done in the realised project is to implement the management of the MV cable network based on the estimated condition of the individual cable line, obtained from diagnostic measurements. The diagnostic investigations of the cable lines are the reference. Many years of research work have led to the development of the Health Index based on diagnostic, technical and service data.

Training-induced changes in muscle contraction patterns enhance exercise performance after short-term neuromuscular electrical stimulation

2020 ◽  
Vol 28 (4) ◽  
pp. 339-350
Author(s):  
Gökhan Umutlu ◽  
Nevzat Demirci ◽  
Nasuh Evrim Acar
Keyword(s):  
Electrical Stimulation ◽  
Muscle Contraction ◽  
Exercise Performance ◽  
Controlled Trial ◽  
Dynamic Control ◽  
Neuromuscular Electrical Stimulation ◽  
Interval Training ◽  
Time To Exhaustion ◽  
Muscle Strengthening ◽  
The Individual

BACKGROUND: Neuromuscular electrical stimulation (NMES) is a complementary tool for therapeutic exercise for muscle strengthening and may potentially enhance exercise performance. OBJECTIVE: To determine whether high-intensity interval training (HIIT) and continuous aerobic training (CA) coupled with NMES enhance the changes in the eccentric/concentric muscle contraction patterns of hamstring and quadriceps. METHODS: Forty-five healthy sedentary male participants performed cycling training 3 times per week for 8 weeks combined with/without NMES performed at a load equivalent to 65% and 120% of IVO2max (intensity associated with the achievement of maximal oxygen uptake). Anthropometrics, blood lactate measurements, IVO2max, TLimVO2max (time-to-exhaustion) and isokinetic strength parameters were measured at baseline and post-training using a randomized controlled trial. RESULTS: The conventional hamstring-to-quadriceps-ratio (HQR: Hcon/Qcon) at 60∘/s and the Dynamic Control Ratio (DCR: Hecc/Qcon) at 180∘/s significantly increased both in the dominant (D) and non-dominant (ND) limb in the HIIT + NMES group (p< 0.05). There was a positive significant correlation between the individual changes in D HQR at 60∘/s and IVO2max (r= 0.94, p= 0.005) and the DCR at 180∘/s and TLimVO2max (r= 0.90, p= 0.015), respectively. CONCLUSIONS: The increases in the eccentric muscle contraction and DCR following HIIT + NMES seem to improve fatigue tolerance, cause less fatigue and oxidative stress on the lower limb during pedaling at high intensities.

Effect of changes in myocardial epinephrine stores on plasma norepinephrine gradient across the dog heart

1994 ◽  
Vol 266 (6) ◽  
pp. H2404-H2409 ◽  
Author(s):  
F. Peronnet ◽  
G. Boudreau ◽  
J. de Champlain ◽  
R. Nadeau
Keyword(s):  
Electrical Stimulation ◽  
Adrenal Medulla ◽  
Pulse Width ◽  
Stellate Ganglion ◽  
Plasma Norepinephrine ◽  
Direct Support ◽  
Left Stellate Ganglion ◽  
Ici 118,551 ◽  
Beta 2 ◽  
Stimulation Of

Plasma norepinephrine (NE) concentration ([NE]) gradient across the heart was measured under electrical stimulation of the left stellate ganglion (LSG; 4 Hz, 4 V, 2 ms pulse width, 1 min) in control (Ctrl) and in adrenalectomized (Adrx) dogs, without and with a 10-min epinephrine (Epi) infusion (92 ng.kg-1.min-1), which partly restored myocardial Epi stores in Adrx dogs (2.9 +/- 0.7 ng/g vs. 6.4 +/- 0.7 ng/g in Ctrl dogs) and slightly increased tissue Epi stores in Ctrl dogs (10.5 +/- 1.3 pg/g). Compared with Ctrl dogs (1,069 +/- 172 pg/ml), the [NE] gradient across the heart under stimulation of the LSG was not modified 1 wk after bilateral adrenalectomy (1,190 +/- 122 pg/ml) or after Epi infusion in Ctrl (1,134 +/- 276 pg/ml) and Adrx (1,259 +/- 279 pg/ml) dogs. The beta 2-antagonist ICI-118,551 significantly reduced the stimulation-induced [NE] gradient across the heart in Ctrl dogs (621 +/- 190 and 603 +/- 86 pg/ml without and with a 10-min Epi infusion, respectively) but not in Adrx dogs deprived of tissue Epi (1,345 +/- 345 pg/ml). Partial repletion of myocardial Epi stores in Adrx dogs restored the effect of ICI-118,551 on the stimulation-induced [NE] gradient (776 +/- 121 pg/ml). These results provide direct support of the hypothesis that tissue Epi, which originates from the adrenal medulla and which is released locally along with NE, is the endogenous agonist for presynaptic beta 2-receptors and potentiates NE release.

scholarly journals Effects of electrical stimulation on isolated rodent gastric smooth muscle cells evaluated via a joint computational simulation and experimental approach

2009 ◽  
Vol 297 (4) ◽  
pp. G672-G680 ◽  
Author(s):  
P. Du ◽  
S. Li ◽  
G. O'Grady ◽  
L. K. Cheng ◽  
A. J. Pullan ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Electrical Stimulation ◽  
Pulse Train ◽  
Pulse Width ◽  
Computational Simulation ◽  
Minimum Energy ◽  
Experimental Studies ◽  
Single Pulse ◽  
Plateau Phase ◽  
Wide Range

Gastric electrical stimulation (GES) involves the delivery of electrical impulses to the stomach for therapeutic purposes. New GES protocols are needed that are optimized for improved motility outcomes and energy efficiency. In this study, a biophysically based smooth muscle cell (SMC) model was modified on the basis of experimental data and employed in conjunction with experimental studies to define the effects of a large range of GES protocols on individual SMCs. For the validation studies, rat gastric SMCs were isolated and subjected to patch-clamp analysis during stimulation. Experimental results were in satisfactory agreement with simulation results. The results define the effects of a wide range of GES parameters (pulse width, amplitude, and pulse-train frequency) on isolated SMCs. The minimum pulse width required to invoke a supramechanical threshold response from SMCs (defined at −30 mV) was 65 ms (at 250-pA amplitude). The minimum amplitude required to invoke this threshold was 75 pA (at 1,000-ms pulse width). The amplitude of the invoked response beyond this threshold was proportional to the stimulation amplitude. A high-frequency train of stimuli (40 Hz; 10 ms, 150 pA) could invoke and maintain the SMC plateau phase while requiring 60% less power and accruing ∼30% less intracellular Ca2+ concentration during the plateau phase than a comparable single-pulse protocol could in a demonstrated example. Validated computational simulations are an effective strategy for efficiently identifying effective minimum-energy GES protocols, and pulse-train protocols may also help to reduce the power consumption of future GES devices.

scholarly journals Does Diabetes Mellitus Alter the Onset and Clinical Course of Vascular Dementia?

2010 ◽  
Vol 23 (3) ◽  
pp. 145-151 ◽  
Author(s):  
Santosh B. Murthy ◽  
Ali Jawaid ◽  
Salah U. Qureshi ◽  
Yogeshwar Kalkonde ◽  
Andrew M. Wilson ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Vascular Dementia ◽  
Neuropsychiatric Symptoms ◽  
Disease Onset ◽  
Multiple Risk Factors ◽  
History Of ◽  
Dementing Illness ◽  
Multiple Variables ◽  
Rate Of Decline ◽  
The Individual

Background:Vascular dementia (VaD) is the second most common dementing illness. Multiple risk factors are associated with VaD, but the individual contribution of each to disease onset and progression is unclear. We examined the relationship between diabetes mellitus type 2 (DM) and the clinical variables of VaD.Methods:Data from 593 patients evaluated between June, 2003 and June, 2008 for cognitive impairment were prospectively entered into a database. We retrospectively reviewed the charts of 63 patients who fit the NINDSAIREN criteria for VaD. The patients were divided into those with DM (VaDDM, n = 29) and those without DM(VaD,n= 34). The groups were compared with regard to multiple variables.Results:Patients with DM had a significantly earlier onset of VaD (71.9 ± 6.54 vs. 77.2 ± 6.03,p< 0.001), a faster rate of decline per year on the mini mental state examination (MMSE; 3.60 ± 1.82 vs. 2.54 ± 1.60 points,p= 0.02), and a greater prevalence of neuropsychiatric symptoms at the time of diagnosis (62% vs. 21%,p= 0.02).Conclusions:A history of premorbid DM was associated with an earlier onset and faster cognitive deterioration in VaD. Moreover, DM was associated with neuropsychiatric symptoms in patients with VaD. A larger study is needed to verify these associations. It will be important to investigate whether better glycemic control will mitigate the potential effects of DM on VaD.

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