Pale, Soft And Exudative Research Articles

Evaluation of parameters for monitoring welfare during transport and lairage at the abattoir in pigs

AbstractNew transport legislation and society demands may increase the need for a ‘fast’ method to assess animal welfare at the abattoir. The objective of this study was to identify valid and feasible parameters which could be easily assessed at slaughterline in pigs. Eight transports (4 ‘far’ and 4 ‘near’ the abattoir) were evaluated using a questionnaire which included both animal-based and environment-based parameters. A ‘welfare index’ (WI) (0 = worst to 1 = best) was estimated for each transport based on the questionnaire. Lean and fat content, skin lesions, pH and electrical conductivity (PQM) were measured in 120 or 60 pigs per transport. When pH > 6 the meat was considered dry, firm and dark (DFD) and when PQM > 9 μs meat was pale, soft and exudative (PSE). Odds ratio between welfare index and slaughterline recordings was estimated. Differences in WI between the different transports were smaller than expected (WI ranged from 0.4 to 0.6). However, a significant relationship between higher percentage of DFD meat and lower welfare index (odds ratio: 2.25) was found. These results suggest that parameters like DFD meat could be used at the abattoir to perform a ‘snapshot’ welfare evaluation.

Use of visible spectroscopy for quality classification of intact pork meat

Many quality characteristics of pork meat are associated with visible characteristics such as color. To develop an objective and nondestructive system to assess the quality of fresh pork meat, the potential of using visible spectroscopy to classify different quality classes of pork meat and to predict CIE L ∗, a ∗ and b ∗ values was investigated. Four different qualities of meat were considered namely RFN (red, firm and non-exudative), RSE (red, soft and exudative), PFN (pale, firm and non-exudative) and PSE (pale, soft and exudative). Reflectance spectra were acquired with a Minolta CM 3500d spectrophotometer in the range from 400 to 700 nm. The data analysis showed that it was possible to separate pale meat from red meat. In addition, PFN meat was distinguishable from PSE meat. However, the visible spectral information is not sufficient to separate all the four quality groups. The classification accuracy of using the reflectance spectra was better than using the L ∗, a ∗ and b ∗ values. The partial least squares regression was used to predict the L ∗, a ∗ and b ∗ values from the visible reflectance spectra. In general, the prediction for L ∗ was better than for the a ∗ and b ∗ values.

Evidence of Significant Effects of Stunning and Chilling Methods on PSE Incidences

The current study was conducted to investigate the optimum stunning voltage and chilling regime with emphasis on reduction in pale, soft and exudative (PSE) pork. The experiments were conducted at seven Korean major pig abattoirs using a total of 91,082 industrial population. Frequencies of PSE meat was found to be significantly (p<0.05) increased as stunning voltage was elevated from 220-240 (13.14%), 250-280 (29.32%) to 430 volts (36.74%). Chilling methods after slaughter, either with cold water showing or rapid chilling reduced PSE meat by 22% compared to a classic chiller-based slow chilling regime. The current study also revealed that chiller temperature during the first 90 minutes had a significant (p<0.001) effect on PSE incidences. Pigs chilled between -5 to 7°C resulted in the lowest PSE meat (17.8%), followed by higher than 7°C (21.3%) and lower than -5°C (37.5%). The current data implies that low voltage stunning method (eg., 220-240 volts), followed by rapid chilling regime, maintaining chiller temperature between approximately -5 to 7°C could reduce PSE incidences.

The colour of the adductor muscle as a predictor of pork quality in the loin

The relation between measurements of colour made in the m. adductor (AD) at 45 min or 20 h post mortem and the quality, assessed subjectively in terms of colour and waterholding capacity, of the m. longissimus (LD) in the loin was examined. The study used data from 100 pig carcasses exhibiting a wide range of meat quality from extreme PSE (pale, soft and exudative) to extreme DFD (dark, firm and dry). The subjective assessments were confirmed by objective measures of paleness (reflectance) and waterholding capacity (drip loss in storage) in the LD. Lightness ( L ∗) measured at 20 h post mortem in the AD was the best potential predictor of loin muscle quality, explaining 59% of the variation in subjective and objective quality measures. Comparable measurements at 45 min post mortem explained between 21% and 44% of the variation. The equation that described the relation between AD Lightness ( L ∗) and subjectively assessed LD quality was derived. This could be used to transpose the AD L ∗ values from a population of slaughtered pigs into nominal subjective scores for the LD, allowing the frequency of the five subjective quality groups (extremely DFD, slightly DFD, normal, slightly PSE, and extremely PSE) in the population of carcasses to be defined.

Rheological characteristics of fresh and frozen PSE, normal and DFD chicken breast meat

1. Textural and rheological differences among broiler breast meat ranging from pale, soft and exudative (PSE) to dark, firm and dry (DFD) in their fresh and frozen (and thawed) forms were investigated. 2. The PSE meat showed significantly higher lightness values and lower pH and water holding capacity values than normal and DFD meats; DFD meat was also significantly different from normal meat. 3. During cooking, PSE meat lost significantly more liquid and produced a softer gel than normal or DFD meats; texture profile analysis parameters were lower for the PSE meat. 4. The storage modulus values (G′, rigidity of elastic response of the gelling material) showed that DFD meat produced a more rigid gel during cooking (especially above 54°C) and later during cooling (back to 30°C) compared with the PSE meat. 5. Freezing resulted in a trend of lower G′ values before, during and after cooking. The results indicated that meat proteins were damaged during freezing and PSE meat was more severely affected, or that more protein denaturation occurred in the PSE meat.

Role of AMP‐activated protein kinase in the glycolysis of postmortem muscle

AbstractAMP‐activated protein kinase (AMPK) is a newly identified kinase controlling energy metabolism in vivo. The objective of this study was to show the role of AMPK in postmortem glycolysis. Rapid and excessive postmortem glycolysis is directly related to the incidence of PSE (pale, soft and exudative) meat in pork, chicken and turkey, while insufficient glycolysis leads to dark cutters in beef and lamb, which causes significant loss to the meat industry. A total of 24 two‐month‐old C57BL/6J mice were assigned to three treatments: (1) wild‐type mice without pre‐slaughter treatment; (2) wild‐type mice with a 2 min swim before slaughter; and (3) wild‐type mice intraperitoneally injected with AICAr (50 mg kg−1), a specific activator of AMPK, to stimulate the activity of AMPK. In addition, 16 two‐month‐old C57BL/6J mice with AMPK knockout were assigned to two treatments: (4) AMPK knockout mice without pre‐slaughter treatment; and (5) AMPK knockout mice with a 2 min swim before slaughter. The longissimus dorsi muscle was sampled at 0, 1 and 24 h postmortem for pH and enzyme activity measurements. Results showed that AMPK activity had a major role in determining the ultimate muscle pH. Pre‐slaughter stress induced by swimming significantly accelerated the glycogenolysis in postmortem muscle through activating glycogen phosphorylase. AMPK is important for maintaining the activity of glycogen phosphorylase and pyruvate kinase, and glycogenolysis/glycolysis in postmortem muscle. Thus, AMPK has an important role in the control of postmortem glycolysis and is crucial for a lower ultimate pH in postmortem muscle. However, the activation of AMPK cannot fully account for the initial rapid glycogenolysis/glycolysis induced by stress and another mechanism must exist for the accelerated glycolysis induced by pre‐slaughter stress. Copyright © 2005 Society of Chemical Industry

Pig sire type and sex effects on carcass traits, meat quality and physicochemical and sensory characteristics of Serrano dry‐cured ham

AbstractThis study demonstrates that improvements in animal line selection by breeding enterprises exert a strong effect on carcass traits, meat quality and sensory characteristics of Serrano dry‐cured ham. A total of 461 pigs from the offspring of a Duroc (DU) × Landrace (LD) sow mated with two DU boars and a DU × Large White (LW) boar from three breeding enterprises were evaluated. The two DU terminal sires were significantly different (P &lt; 0.05) in carcass conformation, backfat thickness, ham and loin yields, raw ham traits, myoglobin concentration and total pigments formed during the curing process; in addition, the two lines provided different percentages of hams (54 vs 91%) with sufficient subcutaneous fat and weight to manufacture dry‐cured Serrano hams using a slow ripening process (11 months). The DU × LW sire had the best carcass and ham traits from an economic standpoint and obtained highest scores for sensory characteristics of Serrano ham evaluated by a trained panel test; furthermore, this line provided 84% of total hams suitable for manufacturing Serrano hams by a slow process. When the sex effect was analysed, carcass and ham traits of females were more favourable, but females presented a higher incidence of pale, soft and exudative (PSE) meat and a lower percentage of hams with sufficient subcutaneous fat and weight to produce Serrano hams using a slow ripening process (61% for females and 91% for castrates). On the other hand, castrates provided Serrano hams cured by a slow procedure with better organoleptic characteristics than females. Right and left hams were similar. Copyright © 2005 Society of Chemical Industry

Effects of pale, normal, and dark chicken breast meat on microstructure, extractable proteins, and cooking of marinated fillets

The effects of chicken breast meat lightness value (L*) on microstructure, protein extraction, and marinating and tumbling was investigated. Pale soft, and exudative (PSE) meat (L* = 57.7, pH 5.72) showed significantly lower salt soluble protein extraction with less heavy myosin chains compared with dark, firm, and dry (DFD) meat (L* = 44.8, pH 6.27). The PSE meat showed larger intercellular spaces among muscle fibers and bundles compared with normal and DFD meat. Marinated and tumbled PSE breast fillets had higher unbound brine compared with the other meats. Further cooking resulted in lower yield and higher shear force values for the PSE meat compared with normal and DFD fillets.

Role of β-Adrenoceptor Signaling and AMP-Activated Protein Kinase in Glycolysis of Postmortem Skeletal Muscle

Postmortem glycolysis is directly linked to the incidences of PSE (pale, soft, and exudative) and DFD (dark, firm, and dry) meats, which cause significant economic loss to the meat industry. However, mechanisms controlling postmortem glycolysis are unclear. The objective of this study was to determine the role of beta-adrenoceptor signaling and AMP-activated protein kinase (AMPK) in postmortem glycolysis. Eighteen 2 month old C57BL/6J female mice were randomly separated into three groups. Group I received an intraperitoneal injection of saline solution only and served as the control; group II received a saline injection and then were forced to swim for 1 min; and group III received an injection of propranolol (1 mg/kg) in saline. In addition, six C57BL/6J female AMPK knockout mice were assigned to group IV, which received a saline injection and were forced to swim for 1 min. The longissimus dorsi muscle was sampled at 0, 1, and 24 h postmortem for pH and enzyme activity measurements. The objective is to elucidate the roles of beta-adrenoceptor signaling and AMPK in the glycolysis of postmortem muscle. Results showed that AMPK activity had a major role in determining the ultimate muscle pH, with an ultimate pH for control mice of 6.16 and AMPK knockout mice of 6.48. The beta-adrenoceptor signaling is essential for initial rapid glycolysis. Blocking beta-adrenoceptor signaling prevented the initial pH decline induced by stress. Activation of beta-adrenoceptor signaling due to preslaughter stress activates glycogen phosphorylase, resulting in a rapid glycolysis shortly after slaughter. On the other hand, the activation of AMPK is important for maintaining the activity of glycogen phosphorylase and pyruvate kinase, leading to a sustained glycolysis and a low ultimate pH.

Development of an autonomous, wireless pH and temperature sensing system for monitoring pig meat quality

This paper focuses on the development of a unique wireless pH and temperature monitoring system to assess pig meat quality. Pale, soft and exudative (PSE) pig meat continues to be a major problem in the pig meat industry today. The PSE condition in pork is related to a number of factors including genetics, pre-slaughter stress and insufficient chilling of pig carcasses, which cause a rapid rate of glycolysis post-mortem (<1 h). As a result the pH drops to low levels while the muscle temperature is still high. A wireless dual channel system that monitors pH and temperature simultaneously has been developed to provide pH and temperature data of the carcass during the first 24 h after slaughter. We have demonstrated that this approach can distinguish in real time, pH and temperature profiles that are ‘non-normal’, and identify carcasses that are PSE positive quickly and easily.

Risk assessment of PSE condition due to pre-slaughter conditions and RYR1 gene in pigs

A polychotomous logistic regression model was used to identify and assess the risk factors for pork meat becoming pale, soft and exudative (PSE). A total of 116 deliveries, comprising 15,695 commercial pigs delivered from different commercial farms to five Spanish pig commercial abattoirs were surveyed. The PSE condition was described as an ordinal response variable (normal, prone to PSE and PSE) based on measurements of electrical conductivity in the Semimembranosus muscle 1–2 h post-mortem. The RYR1 genotype, the abattoir, the season, the gender, the floor surface in the lorry, the loading system, and the stocking density during transportation influenced the risk of PSE condition, as well as on-farm fasting time, loading time, transportation and lairage times. The effect of the RYR1 gene, determined in a subsample of 1331 pigs, was due to nn stress-susceptible pigs, in which the risk of PSE meat (PQM>6 μs) increased fourfold. Abattoirs should be especially careful in summer, when the risk of PSE meat was found to be double that of winter. The risk of PSE meat decreased with the time of transportation, though its effect depended on the stocking density. Thus, our results indicate that, for transits longer than 3 h, the risk of PSE increases with stocking density during transport, while the opposite occurs for shorter transits.

Effects of Stocking Density and Transportation Time of Market Pigs on Their Behaviour, Plasma Concentrations of Glucose and Stress-associated Enzymes and Carcass Quality

It is known that the transportation stress of market pigs can affect their carcass quality and that blood concentrations of glucose, creatine kinase (CK) and lactate dehydrogenase (LDH) are indicators of the transportation stress. Fifty-seven gilts and 57 barrows weighing approximately 110 kg were randomly assigned into six groups in a 3 (high (0.31 m 2 /100 kg BW)-, medium (0.35 m 2 )- and low (0.39 m 2 )-stocking densities)×2 (1 h vs. 3 h transportation time) arrangement of treatments. Blood samples were taken during transportation and after 2 h lairage. The percentage of standing animals during transportation was less in the low- than in the medium- or high-stocking density; the opposite was true for the sitting posture. Plasma concentrations of glucose, CK and LDH increased after loading and declined to the resting levels after lairage. Concentrations of CK and LDH were greater in the 3 h vs. 1 h transportation group. Moreover, the LDH concentration was less in the low- than in the medium- or high-density group. Also detected was a significant interaction between the stocking density and transportation time in all of these blood variables. The incidence of pale, soft and exudative (PSE) carcass was greatest in the high-stocking density group. Interestingly, the PSE incidence increased following the 3 h vs. 1 h transportation at the low-density, but not at the medium-density. Results suggest that the medium-density may be preferable to the low- density in the long-distance transportation. (Asian-Aust. J. Anim. Sci. 2004. Vol 17, No. 1 : 116-121)

Meat production using four terminal pig lines

AbstractThe influence of terminal sire (Duroc (D1 and D2), Large White/Pietrain (LW/P) and Large White (LW)) on several meat production and meat quality traits was investigated in 452 male and female offspring of Landrace/Large White dams. Age at slaughter, carcass length, carcass weight and dressing yield were similar for all lines, as was the production of shoulders, chops, and ribs with bacon. D2‐sired pigs produced more noble pieces as a percentage of their carcass weight than the other three lines. LW/P‐ and LW‐sired pigs were generally leaner than Duroc‐sired pigs. LW/P and LW pigs had the highest percentage of cuts (longissimus dorsi and semimembranosus muscle) classified as pale, soft and exudative (PSE) meat. There were no large differences between the lines in the occurrence of dark, firm and dry (DFD) cuts. Copyright © 2003 Society of Chemical Industry

Effects of dietary magnesium and halothane genotype on performance and carcass traits of growing-finishing swine

Halothane-negative (NN) and halothane-carrier (Nn) pigs were assigned randomly to one of three dietary treatments: (1) control corn–soybean meal diets; (2) control diets supplemented with 1.25% magnesium mica (MM); or (3) control diets supplemented with 2.5% MM. When the lightest block averaged 108.8 kg, pigs were harvested at a commercial pork slaughter plant, and bone-in pork loins were captured, vacuum-packaged and transported back for measurement of pork quality traits. The NN pigs had greater average daily gain (ADG) during the grower ( P<0.05) and finisher ( P<0.05) periods than Nn pigs. Although MM had no effect ( P>0.10) on ADG, pigs fed 1.25% MM had a higher ( P<0.05) gain-to-feed ratio (G:F) during the grower phase than pigs fed 2.5% MM; whereas, pigs fed control diets had an intermediate G:F. Carcasses from Nn pigs were leaner ( P<0.05) and heavier ( P<0.05) muscled than carcasses from NN pigs. In contrast, a greater ( P<0.05) percentage of carcasses from Nn pigs received color scores characteristic of the pale, soft and exudative (PSE) condition. Although there were distinct genotype effects on performance and carcass traits, long-term supplementation of diets with MM had no beneficial, or deleterious, effects on pork quality or carcass yield.

Effects of the stunning procedure and the halothane genotype on meat quality and incidence of haemorrhages in pigs

A total of 313 pigs (127 halothane-free, NN, and 186 heterozygous halothane, Nn) were slaughtered in four batches at two commercial abattoirs with two different stunning systems, an automatically head-only followed by head-to-chest electrical stunner and a compact carbon dioxide (CO2) stunning unit. Meat quality on the loin muscle was assessed by measuring electrical conductivity (PQM) and colour (Minolta CR 200) at 7 h post mortem, and ultimate pH. Loins showing PQM >6.0 μs were classified as clearly pale, soft and exudative (PSE) meat. The incidence of petechiae, ecchymosis and haematomas in the shoulders, loins and hams was also evaluated. In the abattoir equipped with the electrical stunning system, a higher incidence of potentially PSE meat was found compared with the abattoir equipped with CO2 stunning (35.6 vs. 4.5%). Likewise, electrical stunning increased significatively the incidence of petechiae in the loins, shoulders and hams, and ecchymosis in the loins and hams. Also, the incidence of PSE meat was higher in the Nn pigs compared with NN pigs (24.7 vs. 7.9%). It is suggested that for improving meat quality and reducing incidence of haemorrhages electrical stunning should be avoided. Further improvements in meat quality can be achieved by eliminating the halothane gene specially in CO2-stunned pigs.

Improvement of the physicochemical properties of pale soft and exudative (PSE) pork meat products with an extract from mechanically deboned turkey meat (MDTM)

Loss of protein functionality of pale soft and exudative (PSE) meat and a surplus of mechanically deboned turkey meat (MDTM) has negative economic impacts on the meat industry. The objective of this research was to add functional proteins from an extract of MDTM to PSE meat to create a value-added pork sausage product. Sausages manufactured from PSE incorporating an MDTM extract exhibited a 30% increase in rigidity ( P<0.05) compared to those manufactured using brine alone. Sausages made from PSE and normal pork with the MDTM extract demonstrated little difference in water holding capacity ( P>0.05), and reductions of 4.1 and 3.1% in cooking loss ( P<0.05), respectively, compared to sausages made employing brine alone. Introducing functional proteins derived from MDTM to processed meat made with PSE pork has the potential to enhance the economic value to both of these low value raw materials.

Pork meat quality affects peptide and amino acid profiles during the ageing process

Twenty pork carcasses were classified in different pork meat qualities: red, firm and non-exudative (RFN), pale, soft and exudative (PSE), red, soft and exudative (RSE) and dark, firm and dry (DFD) meat. The content of peptides and free amino acids during the ageing process was analysed and compared within quality classes. Four peptide fractions were isolated through cation-exchange and reverse-phase chromatography. The main significant differences among qualities were obtained for peptide fractions 3 and 4. Peptide fraction 3 at 4 days and peptide fraction 4 at 2 h postmortem were higher in the ideal pork quality (RFN) than in the other quality classes. The ageing of pork meats produced a general increase in all free amino acid concentrations for the studied quality classes except for Gln, β-Ala, Taurine and Orn and the dipeptides carnosine and anserine. The DFD class showed higher increases in Lys, Ala and Met probably due to the activation of neutral aminopeptidases.

Early Postmortem Detection of Exudative Pork Meat Based on Nucleotide Content

ABSTRACT:The content of nucleotide metabolites in the muscle L. dorsi was analyzed for the detection of pale, soft and exudative (PSE) pork meats at just 2 h postmortem. PSE meat was characterized by significantly lower (p &lt; 0.05) amounts of adenosine 5′‐triphosphate (ATP) and higher adenosine 5′‐monophosphate (AMP), inosine 5′‐monophosphate (IMP), inosine (ino) and hypoxanthine (hyp) than normal meat. IMP and ino classified all the samples from both groups with statistical significance (p &lt; 0.05). The K0 value, R′ value and IMP/ATP ratios were also useful indicators for full distinction of PSE meats. Thus, the assay of any of these nucleotide metabolites may allow a good detection of PSE meats at very short, only 2 h, postmortem time.

Historical perspectives and current aspects of pork meat quality in the USA

The condition of pale, soft and exudative (PSE) pork meat was recognized and documented by 1960, and the condition of porcine stress syndrome (PSS) was understood within the decade of the 1960s. The two are associated, with PSS animals having a high probability of producing PSE meat. Both are economically important with potential death losses, especially during transport, due to PSS, and PSE meat being viewed as of inferior quality by consumers and also having less value for further processing. An enormous amount of research has been directed at the problem and is presented in the manuscript as a time-line approaching a half-century of effort. Surveys of incidence showed, in pork produced in the USA, that 18% was PSE in 1963 and 16% was PSE in 1992. Fortunately, molecular/genetic understanding and tools are now available to attack the problem, but solving it may require further impetus — such as strong and unified resolution by producers, industry associations and governmental agencies.

Objectively Predicting Ultimate Quality of Post-Rigor Pork Musculature:II. Practical Classification Method on the Cutting-Line

To investigate the practical assessing method of pork quality, 302 carcasses were selected randomly to represent commercial conditions and were probed at 24 hr postmortem (PM) by Danish Meat Quality Marbling (MQM), Hennessy Grading Probe (HGP), Sensoptic Resistance Probe (SRP) and NWK pH-K21 meter (NpH). Also, filter paper wetness (FPW), lightness (L*), ultimate pH (pHu), subjective color (SC), firmness/wetness (SF) and marbling scores (SM) were recorded. Each carcass was categorized as either PSE (pale, soft and exudative), RSE (Reddish-pink, soft and exudative), RFN (reddish-pink, firm and non-exudative) or DFD (dark, firm and dry). When discriminant analysis was used to sort carcasses into four quality groups the highest proportion of correct classes was 65% by HOP 60% by MQM 52% by NpH and 32% by SRP. When independent variables were combined to sort carcasses into groups the success was only 67%. When RSE and RFN groups were merged so that there were only three groups (PSE, RSE+RFN, DFD) differentiating by color MQM was able to sort the same set of data into the new set of three groups with 80% accuracy. The proportions of correct classifications for HGP, NpH and SRP were 75%, 61% and 35% respectively. There was a decline in predication accuracy when only two groups, exudative (PSE and RES) and non exudative (RFN and DFD) were sorted. However when two groups designated PSE and non-PSE (RSE, RFN, and DFD) were sorted then the proportion of correct classification by MQM, HGP, SRP and NpH were 87%, 81%, 71% and 66% respectively. Combinations of variables only increased the prediction accuracy by 1 or 2% over prediction by MQM alone. When the data was sorted into three marbling groups based on SM this was not well predicted by any of the probe measurements. The best prediction accuracy was 72% by a combination of MQM and NpH.