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Huanglongbing (HLB), caused by Candidatus Liberibacter asiaticus, is currently the most destructive disease of citrus and threatens production in all affected areas. There is no cure. Benign Xylella fastidiosa strain EB92-1 provided good control of Pierce's disease of grapevine by inducing host resistance; therefore, we evaluated the strain for the biological control of HLB in citrus. Treatment was by injection into the trunk of the trees. Strain EB92-1 was shown to colonize citrus and provided control of HLB by reducing both the incidence of symptomatic trees and the percentage of trees with severe symptoms in three separate trials. All trees were positive by quantitative PCR (qPCR) for Candidatus Liberibacter asiaticus at the start of the trials, and treatment did not eliminate the bacterium. In a trial of asymptomatic mature trees, a single treatment with EB92-1 reduced the incidence of trees with symptoms through 18 months after treatment and reduced the incidence of trees with severe symptoms through 3 years. In mature trees that had 60% incidence of mild HLB symptoms at trial initiation, percentage of trees with symptoms and trees with severe symptoms continued to develop in both the untreated and in the EB92-1-treated trees for 12 months. However, retreatment at 9 and 20 months prevented the development of additional severe symptoms in the EB92-1-treated trees throughout the remainder of the 5-year trial. In 2-year-old trees, incidence of trees with HLB symptoms was higher in the untreated trees than in the treated trees throughout the 6 years of the trial, reaching 90% in the untreated versus 50% in the treated. After 6 years, severity of symptoms was much lower in the EB92-1-treated trees, only 3% of the treated trees had become unproductive compared with 18% of the untreated. In 2020, the reduction in HLB severity resulted in approximately twice as much yield in the treated trees as in these untreated 8-year-old trees. X. fastidiosa strain EB92-1 proved to be efficacious for the control of HLB symptoms in both mature trees and newly planted young trees, but trees may need to be retreated yearly for at least the first 2 to 3 years.

Data from samples of longissmus lumborum (LL) and semimembranosus (SM) muscles from 391 lamb carcasses, which had been packaged in overwrap (OW) or high oxygen modified atmosphere packaging (MAP O2 ) systems and then subjected to simulated retail display, were used to estimate genetic variation for colour stability traits of lamb meat as a step in identifying a trait for genetic evaluation. Traits included the ratio of the reflectance of light at wavelengths of 630 nm and 580 nm (oxy/met) measured at a single time point at the end of the display period (day 3 under OW; day 8 under MAP O2 ) and the predicted time for oxy/met to reach a benchmark value. Under OW and MAP O2 , the measures of meat colour stability of the LL tended to be of moderate heritability (0.09-0.29), but for the SM were of low heritability (0-0.10). Improving retail colour stability of lamb loins through selection of genetically superior animals may be better based on measurement of oxy/met., (Crown Copyright © 2019. Published by Elsevier Ltd. All rights reserved.)

Dietary supplementation of vitamin E (VitE) in a synthetic or natural form was examined. Forty-eight lambs were assigned (n = 16) to either a grain-based diet at moderate (MOD, 42 mg∙kg -1 VitE as all-rac α-tocopheryl acetate) or supranutritional (SUP, 285 mg∙kg -1 of vitE) levels of synthetic VitE or a lucerne hay-based diet (LUC; 37 mg∙kg -1 VitE) for 8 weeks. Meat from the LUC group had lower muscle n-6 and PUFA levels compared to meat from the MOD and SUP groups. Despite a similar VitE intake, muscle VitE was higher for LUC compared to MOD, while SUP lambs showed the highest VitE. Lipid oxidation did not differ between groups. For fresh meat, redness tended to be higher in LUC fed lambs than the other two groups, but brownness formation was only lower than the SUP group. For aged meat colour stability, redness tended to be higher in lambs fed SUP and LUC, whereas highest browning occurred in the MOD group., (Crown Copyright © 2018. Published by Elsevier Ltd. All rights reserved.)

This review discusses the importance of red meat from ruminants as a source of omega-3 (n-3) fatty acids (FAs) for human life in the context of the contribution of animals to human welfare. Red meat is a valuable food commodity for human life because it is naturally rich in key nutrients such as protein, trace elements, vitamins and essential FAs. In developed countries and high socio-economic groups from developing countries, red meat intake is greater than that of oily fish, owing to availability, preference and affordability. Omega-3 FA concentration is higher in red meat (beef, lamb and mutton) than in white meat (pork, poultry and turkey), due to the fibre types present in muscle tissues and the specialised digestive systems of ruminants. There is mounting evidence that regular consumption of n-3 FAs is beneficial for growth and development as well as the health and welfare of humans of all ages. The dietary background of ruminants significantly influences the concentration of n-3 FAs in red meat. Meat from forage- or grassfed ruminants has a greater concentration of n-3 FAs than that from their feedlot or grain-fed counterparts and can also offer a favourable n-6:n-3 ratio in the meat. Scientific literature shows that the advantages of consuming n-3 FAs enriched meat (foods) outweigh the disadvantages.

The current study examined the effect of vascular rinsing lamb carcases (Rinse & Chill®) with a commercially available isotonic substrate solution (98.5% water; balance: glucose, polyphosphates, and maltose) at 14°C. Thirty, lamb carcases were randomly allocated to receive either the solution (n=15) 25 min post slaughter on a slaughter line or no solution (n=15). There was no apparent effect on the rate of pH decline due to infusion or muscle shortening of the M. longissimus thoracis et lumborum (LL), but there was a more than 50% reduction in toughness (lower shear force) of the LL due to infusion. Infusion resulted in lighter (L*), yellower (b*) LL and this effect was maintained during simulated colour display. There was no impact on redness (a*) of the LL and in fact a critical consumer threshold for redness was not breached on average for infused or non-infused LL. There was no evidence of elevated levels of metmyoglobin formation or lipid oxidation., (Copyright © 2017. Published by Elsevier Ltd.)

The journal Meat Science was first published in 1976/77 and it initially comprised 4 issues per year. The first issue contained 4 papers and the first volume (4 issues) contained 27 articles, a mixture of papers and research notes. Its growth/popularity increased, and it has continued to thrive and in 2016 of the 1010 papers processed 292 were accepted. Over 90% of the papers published in the first volume were concerned with muscle biochemistry/meat properties. During the last years of the 20th century, meat products and their properties became a far larger proportion of the submissions as did those concerned with nutrition and safety. More recently there has been a resurgence of papers concerned with meat quality. Over the last 40years, the journal has reported on the major developments in meat science research and this paper will discuss both the history of the journal, and aspects of meat research as reflected in its publications. Possible future research trends are also discussed., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Genetic correlations between 29 wool production and quality traits and 25 meat quality and nutritional value traits were estimated for Merino sheep from an Information Nucleus (IN). Genetic correlations among the meat quality and nutritional value traits are also reported. The IN comprised 8 flocks linked genetically and managed across a range of sheep production environments in Australia. The wool traits included over 5,000 yearling and 3,700 adult records for fleece weight, fiber diameter, staple length, staple strength, fiber diameter variation, scoured wool color, and visual scores for breech and body wrinkle. The meat quality traits were measured on samples from the and included over 1,200 records from progeny of over 170 sires for intramuscular fat (IMF), shear force of meat aged for 5 d (SF5), 24 h postmortem pH (pHLL; also measured in the , pHST), fresh and retail meat color and meat nutritional value traits such as iron and zinc levels, and long-chain omega-3 and omega-6 polyunsaturated fatty acid levels. Estimated heritabilities for IMF, SF5, pHLL, pHST, retail meat color lightness (), myoglobin, iron, zinc and across the range of long-chain fatty acids were 0.58 ± 0.11, 0.10 ± 0.09, 0.15 ± 0.07, 0.20 ± 0.10, 0.59 ± 0.15, 0.31 ± 0.09, 0.20 ± 0.09, 0.11 ± 0.09, and range of 0.00 (eicosapentaenoic, docosapentaenoic, and arachidonic acids) to 0.14 ± 0.07 (linoleic acid), respectively. The genetic correlations between the wool production and meat quality traits were low to negligible and indicate that wool breeding programs will have little or no effect on meat quality. There were moderately favorable genetic correlations between important yearling wool production traits and the omega-3 fatty acids that were reduced for corresponding adult wool production traits, but these correlations are unlikely to be important in wool/meat breeding programs because they have high SE, and the omega-3 traits have little or no genetic variance. Significant genetic correlations among the meat quality traits included IMF with SF5 (-0.76 ± 0.24), fresh meat color * (0.50 ± 0.18), and zinc (0.41 ± 0.19). Selection to increase IMF will improve meat tenderness and color which may address some of the issues with Merino meat quality. These estimated parameters allow Merino breeders to combine wool and meat objectives without compromising meat quality.

The longissmus lumborum (LL) and semimembranosus (SM) muscles from 391 lamb carcasses, derived from various breed types, were used to investigate the effect of animal/muscle factors, packaging type [over-wrap (OW) or high oxygen modified atmosphere packaging (MAP O2 )] and duration of display on redness of meat during simulated retail display. Using statistical models the time required (in days) for redness to reach a threshold value of 3.5 (below this is unacceptable) was predicted. High levels of iron in the SM, but not LL, reduced the time for redness to reach 3.5 by 2-2.6days in MAP O2 and 0.5-0.8days in OW. The greater the proportion of Merino breed type, the shorter was the time for redness to reach the value of 3.5, an effect consistent across muscles and packaging types. In summary, breed type, packaging format, muscle and muscle iron levels had a significant impact on colour stability of sheep meat in oxygen-available packaging systems., (Copyright © 2017. Published by Elsevier Ltd.)

This study was conducted to determine whether circulating concentrations of blood isoprostanes can be used as an effective biomarker in lambs to predict degradation of color and/or lipid stability in meat. Lambs ( = 84) were fed diets of either lucerne pasture, annual ryegrass pasture, a commercial feedlot pellet, or a combination of annual ryegrass and feedlot pellet for 8 wk, including a 2-wk adaptation period. Blood isoprostane concentration at wk 0, 4, 6 or 8 of feeding was determined. Blood isoprostane concentration for each animal was then correlated with muscle biochemical components that impact color and/or lipid oxidative status during retail display. This included lipid oxidation levels in muscle assessed by thiobarbituric acid reactive substances and meat redness determined by a HunterLab colorimetric spectrometer. Lambs that consumed the commercial feedlot pellet had a lower muscle vitamin E level (< 0.01) and a greater level of -6 PUFA ( < 0.001) compared with lambs finished on annual ryegrass or lucerne. Lipid oxidation levels were greatest for lambs finished on the feedlot ration, lowest in lambs finished on the ryegrass diet, and intermediate for lambs finished on lucerne and ryegrass-feedlot combination ( < 0.01). After 8 wk of feeding, blood isoprostane concentration was positively correlated with lipid oxidation of meat displayed for 72 h in simulated retail conditions ( < 0.01). There was a negative linear relationship between isoprostane concentration and muscle vitamin E concentration ( = 0.07), lipid oxidation and muscle vitamin E concentration ( < 0.01) but a positive linear relationship between isoprostane concentration and muscle -6 PUFA ( < 0.001) or lipid oxidation and muscle -6 PUFA concentration ( < 0.001). Blood isoprostane concentration and lipid oxidation in meat were influenced by muscle vitamin E and -6 PUFA but not by -3 PUFA. There was no significant relationship observed between blood isoprostane concentration at 0, 4, 6 or 8 wk feeding vs. overall meat color (redness of meat) at 0 and 72 h of display, stored under simulated retail conditions. The results indicate that circulating blood isoprostane concentration can be a useful tool to predict the oxidative status of postmortem meat. Future work will examine the impact of this relationship on meat flavor/aroma deterioration post farm.

Genetic correlations between 29 wool production and quality traits and 14 whole carcass measures and carcass component traits were estimated from the Information Nucleus of 8 flocks managed across a range of Australian sheep production environments and genetically linked. Wool data were from over 5,000 Merino progeny born over 5 yr, whereas carcass data were from over 1,200 wether progeny of over 176 sires, slaughtered at about 21 kg carcass weight, on average. Wool traits included yearling and adult records for wool weight, fiber diameter, fiber diameter variation, staple strength, scoured color, and visual scores for breech and body wrinkle. Whole carcass measures included HCW, dressing percentage (DP), and various measures of fat depth and eye muscle dimensions. Carcass components were obtained by dissection, and lean meat yield (LMY) was predicted. Heritability estimates for whole carcass measures ranged from 0.12 ± 0.08 to 0.35 ± 0.10 and ranged from 0.17 ± 0.10 to 0.46 ± 0.10 for carcass dissection traits, with no evidence of important genotype × environment interactions. Genetic correlations indicated that selection for increased clean wool weight will result in reduced carcass fat (-0.17 to -0.34) and DP (-0.48 ± 0.15), with little effect on carcass muscle. Selection for lower fiber diameter will reduce HCW (-0.48 ± 0.15) as well as carcass fat (0.14 to 0.27) and muscle (0.21 to 0.50). There were high genetic correlations between live animal measures of fat and muscle depth and the carcass traits (generally greater than 0.5 in size). Selection to increase HCW (and DP) will result in sheep with fewer wrinkles on the body (-0.57 ± 0.10) and barer breeches (-0.74 ± 0.12, favorable), with minor deterioration in scoured wool color (reduced brightness and increased yellowness). Selection for reduced fat will also result in sheep with fewer body wrinkles (-0.42 to -0.79). Increasing LMY in Merinos through selection would result in a large reduction in carcass fat and DP (-0.66 to -0.84), with a smaller increase in carcass muscle and some increase in wool weight and wrinkles. Although no major antagonisms are apparent between the wool and carcass traits, developing selection indexes for dual-purpose wool and meat breeding objectives will require accurate estimates of genetic parameters to ensure that unfavorable relationships are suitably considered. The findings will aid development of dual-purpose wool and meat breeding objectives.

This study investigated the effects of feeding a mixed grain supplement and tenderstretching (TS) alpaca carcasses on meat quality. A total of 56 castrated 24month old alpacas were divided into two treatments (pasture-only, and pasture plus supplementation). Supplemented groups were fed a mixed grain ration in addition to ad lib pasture for 10weeks. Animals were slaughtered across two kill days (n=28). One half of each carcass was suspended by the pelvis (TS) prior to chilling, and the other half was Achilles tendon hung (AH). After 24h, muscles were removed and aged for 10 and 25d. TS significantly increased sarcomere length and reduced shear force and cooking loss in the m. semimembranosus. This trend was not observed in other muscles including the m. longissimus thoracis et lumborum (LL) and m. psoas major. Ageing period resulted in a marginal improvement in LL tenderness. There is clear evidence that TS improves tenderness in the hindquarter of alpacas., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Meat quality parameters for 50 huacaya alpacas, representing three age groups (18, 24 and 36months) and two genders (females and castrated males) were studied. Prior to chilling, samples of m. longissimus thoracis et lumborum (LL) were taken to determine isocitrate dehydrogenase activity and glycogen concentration, and further meat quality samples were taken after 24h. Alpaca meat has low levels (<1%) of intramuscular fat in the LL, m. semimembranosus and m. biceps femoris, but the level in the LL increases with animal age, with levels of desirable polyunsaturated fatty acids (PUFA) ranging from 96.3 to 136.4mg/100g. Lipid oxidisation post retail display ranged from 1.27 to 1.96MDA/kg meat. Colour stability testing indicated alpaca meat was relatively stable during retail display with day of display having no significant effect on lightness (L*), or the 630nm/580nm ratio. These results may relate to the high proportion (76%) of glycolytic and type IIX muscle fibres in LL., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

A small angle X-ray scattering (SAXS) synchrotron was used to evaluate 100 ovine m. longissimus lumborum, representing lamb (n=50) and sheep (n=50). The diffraction of X-rays gives information on muscle myofibril structure and fat content. The linear relationships between SAXS measures with measures such as, shear force, intramuscular fat content (IMF) and collagen content/solubility, were investigated. A relationship was found between the d-spacing of the actin/myosin fibril spacing (SAX1 and SAX2) and the cross sectional area of the rhombohedral unit cell (Cell area) and shear force after 1 and 5day ageing. There was a positive relationship between IMF and a SAXS Fat area measure. There was a muscle site effect on SAX1, SAX2 and Cell area, with the cranial site having a larger distance between myofibrils. The potential of SAXS as a powerful research tool to determine not only the structural components of ovine tenderness, but also the fat content related to IMF is evident., (Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.)

Up to six (average 4.63) replicate compression values were collected on cooked m. semimembranosus of lambs that had been raised at six sites across southern Australia (n=1817). Measurements on each sample were made with one of two Lloyd Texture analyser machines, with each machine having a 0.63 cm diameter plunger. Based on a log normal model with common variance on the log scale for within sample replicate results, estimates of the within sample variability of compression values were obtained, resulting in a quality control procedure for compression testing based on the coefficient of variation., (Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.)

This study investigated the effects of using medium voltage (~300 V) electrical stimulation (ES) and ageing on alpaca meat. A total of 50 huacaya alpacas were distributed across three age groups (18, 24 and 36 months) and two genders (females and castrated males). At 24h post mortem the m. longissimus thoracis et lumborum (LL) and m. semimembranosus (SM) muscles were removed and aged for either 5 or 10 days. In comparison to non-ES samples, ES significantly reduced: LL purge values by 3.0% and LL shear force (SF) at 5 and 10 days (by 21.6N and ageing further reduced tenderness by 6.6N), and SM SF by 5.8 N with significant age effects observed in both ES and non-ES SM samples, such that SF increased by 0.53 N with each month increase in animal age. Consumers rated ES samples higher on tenderness, juiciness, flavour and overall rating. ES and ageing of alpaca carcasses are recommended., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Carcass traits and saleable meat yield (SMY) of female and castrated male alpacas in Australia at 18, 24 and 36 months of age were investigated. Fifty huacaya alpacas, evenly distributed across 14, 20, 32 month ages and two genders, were grazed on coastal summer pastures for four months. Dressing percentage and carcass length were collected at slaughter. At 24h post-mortem the carcasses were prepared into four SMY combinations. Thirty six month animals had heavier hot carcass weights (33.7 ± 1 kg) and longer carcasses (81.2 ± 0.7 cm) as expected. The percentage of total carcass bone (17.5 ± 0.2%), fat trim (1.4 ± 0.1%) and meat trim (7.8 ± 0.4%) was assessed as a proportion of cold carcass weight. The proportion of fat increased and bone decreased with age. Females had more trim than males. SMY decreased in females and increased in males with age across all combinations suggesting that males are preferable for meat production., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

The Warner-Bratzler shear force (WBSF) of 335 lamb m. longissimus lumborum (LL) caudal and cranial ends was measured to examine and simulate the effect of replicate number (r: 1-8) on the precision of mean WBSF estimates and to compare LL caudal and cranial end WBSF means. All LL were sourced from two experimental flocks as part of the Information Nucleus slaughter programme (CRC for Sheep Industry Innovation) and analysed using a Lloyd Texture analyser with a Warner-Bratzler blade attachment. WBSF data were natural logarithm (ln) transformed before statistical analysis. Mean ln(WBSF) precision improved as r increased; however the practical implications support an r equal to 6, as precision improves only marginally with additional replicates. Increasing LL sample replication results in better ln(WBSF) precision compared with increasing r, provided that sample replicates are removed from the same LL end. Cranial end mean WBSF was 11.2 ± 1.3% higher than the caudal end., (Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.)

Subtle breed differences exist for meat quality traits and the Merino does stand out, although many comparisons are confounded by production site or lack of processing intervention. Despite this, the Merino does seem to have a propensity to produce meat with a higher pH and reduced colour stability under extended ageing. Use of the Merino in a crossbreeding system not only provides benefits from hybrid vigour, but also overcomes the meat quality constraints of pure Merinos. Genetic evaluation for lamb production has enabled impressive genetic gains, but an overemphasis on lean meat production has had to be addressed to counter adverse effects on meat quality traits like eating quality. In this regard, the development of genomic selection has provided a methodology for accurate prediction of genetic merit and applying balanced breeding objectives. The potential for negative meat quality effects has stemmed adoption of non-castration approaches, but ensuring that lamb is young when slaughtered does provide brand integrity., (Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.)

The current study examined the effect of supplementing lambs with algae. Forty, three month old lambs were allocated to receive a control ration based on oats and lupins (n=20) or the control ration with DHA-Gold™ algae (~2% of the ration, n=20). These lambs came from dams previously fed a ration based on either silage (high in omega-3) or oats and cottonseed meal (OCSM: high in omega-6) at joining (dam nutrition, DN). Lamb performance, carcase weight and GR fat content were not affected by treatment diet (control vs algae) or DN (silage vs OSCM). Health claimable omega-3 fatty acids (EPA+DHA) were significantly greater in the LL of lambs fed algae (125±6mg/100g meat) compared to those not fed algae (43±6mg/100g meat) and this effect was mediated by DN. Supplementing with algae high in DHA provides a means of improving an aspect of the health status of lamb meat., (Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.)

Coopworth cross lambs born over three years were examined in this study. Differences between two machines; a computer tomography (CT) scanner and a VIAScan® system for the estimation of carcase lean weight in lamb carcases was examined. The CT scanner provided a significantly higher estimate of carcase lean. The rank correlation (0.84) between the CT scanner and the VIAScan® system for the prediction of carcase lean was significant, but there was a different ranking for carcase lean depending on which machine was used. This has important ramifications for the use of VIAScan® data in the New Zealand Sheep Improvement Ltd genetic programme., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Genetic parameters were estimated for a range of meat quality traits recorded on Australian lamb meat. Data were collected from Merino and crossbred progeny of Merino, terminal and maternal meat breed sires of the Information Nucleus programme. Lambs born between 2007 and 2010 (n=8968) were slaughtered, these being the progeny of 372 sires and 5309 dams. Meat quality traits were found generally to be of moderate heritability (estimates between 0.15 and 0.30 for measures of meat tenderness, meat colour, polyunsaturated fat content, mineral content and muscle oxidative capacity), with notable exceptions of intramuscular fat (0.48), ultimate pH (0.08) and fresh meat colour a* (0.08) and b* (0.10) values. Genetic correlations between hot carcass weight and the meat quality traits were low. The genetic correlation between intramuscular fat and shear force was high (-0.62). Several measures of meat quality (fresh meat redness, retail meat redness, retail oxy/met value and iron content) appear to have potential for inclusion in meat sheep breeding objectives., (© 2013.)

This study examined the relationship between collagen content as determined by hydroxyproline assay with other measures of connective tissue, shear force and tenderness in lamb muscle. Samples were taken from both m. longissimus lumborum (LL, loin) and the m. semimembranosus (SM, topside) of 99 lambs. Sensory tenderness and compression of the LL were not correlated to any measure of collagen or connective tissue, with one exception where compression was correlated (r=-0.28; P<0.05) to the percentage of connective tissue determined by imaging. Intramuscular fat (IMF) was linearly correlated (P<0.05) to sensory tenderness and compression, such that a 1% increase in IMF increased the tenderness score by 2.3±0.83 units and reduced compression by 0.73±0.21 N. There was no correlation between SM shear force and collagen concentration. The data suggest that measurement of collagen concentration did not explain the variation in shear force and sensory tenderness observed in the meat from lambs., (Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.)

A study of factors (ageing period, rigor temperature and vitamin E level) impacting on the colour stability of lamb m. longissimus thoracis et lumborum (LL) during 3 days of simulated retail display was undertaken. The LL were taken from 84 lambs from 3 slaughters. Slices of LL were measured fresh (24h post-mortem) or after ageing for 5 days in vacuum packaging. The oxy/met ratio (630/580 nm), declined with display time, and increased with increasing temperature at pH6.0. Redness (a*) values also declined with display time and a reduction in redness values was observed as LL pH at 24h post-mortem and/or pH at 18°C increased. There was no effect of ageing period or vitamin E level on the oxy/met ratio or a* values when the vitamin E level averaged 3.76 mg/kg LL. These results suggest that maximising vitamin E levels in lambs and achieving a moderate rate of pH decline will optimise colour stability irrespective of ageing period., (Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.)

Twenty-four entire male Kacang kid goats were fed diets containing 3% canola (n=12) or palm oil (n=12) supplements for 16 weeks. The goats had an initial live weight of 14.2±1.46 kg and were fed a mixed ration ad libitum (10.4 MJ/ME and 14% crude protein). There was no difference in feedlot performance due to diet. Inclusion of canola oil reduced (P<0.05) kidney fat weight and increased (P<0.05) linolenic acid (18:3n-3) concentration in the blood plasma, m. longissimus lumborum (LL), liver, and kidney. The palm oil diet increased (P<0.05) myristic (14:0) and palmitic (16:0) acid content in the blood, but this did not alter these fatty acids in the LL muscle. Lipid oxidative substances in the liver and LL from palm oil fed kids were higher (P<0.05) than those from canola supplemented kids. The incorporation of canola oil into the goats' diet increased muscle omega-3 fatty acid content, but lipid oxidation was lowered in the blood and muscle LL., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

A comparison of peak shear force results for a Lloyd texture analyser fitted with a Warner Bratzler type of shearing head and a G2 Tenderometer was undertaken using sheep meat. The G2 is a new version of the Tenderometer that uses an electric linear motor to compress the sample, but still retains the blunt wedge-shaped "tooth". Analysis of sheep meat samples (n=121) revealed that the average G2 Tenderometer shear force results were approximately 1.2 times those for the Lloyd based on the following model; Lloyd=1.561 Tenderometer(0.84). Both instruments explained low amounts of the variation (less than 20%) in the sensory traits tenderness and overall liking. The high values for the sensory traits indicate that a wider range of samples, including samples with lower sensory scores, is required to develop robust threshold estimates so that either instrument could be use as an auditing instrument for the processing industry., (Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.)

An evaluation of the Hennessy Grading Probe (HGP) was undertaken using 557 lamb carcases for the measurement of subcutaneous fat depth (Fat C) and muscle depth (EMD; m. longissimus thoracis et lumborum (LL)) between the 12th/13th ribs. All carcases were probed on the moving chain at up to 10 carcases per min and data analysis was constrained to 320 carcases which were probed at the target site (over the greatest depth of the LL at the midpoint between the 12th and 13th ribs). Analysis of the data revealed wide variability between HGP and equivalent carcase measures, but probe type (versions GP4 and GP7) had minimal impact on the usefulness of the HGP. The HGP as used in the study does not appear to be a viable option for the Australian sheep processing industry., (Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.)

This study evaluated the interaction between medium voltage electrical stimulation, SmartStretch™ stretching and ageing treatments on key meat quality traits of hot boned sheep m. semimembranosus. Medium voltage stimulation reduced initial pH (P<0.001), but did not impact on other meat quality traits. There was a significant interaction between stretch treatment and ageing (P<0.001) for shear force such that samples which were both stretched and aged were the most tender. Sarcomere length was significantly (P<0.001) increased by SmartStretch™ treatment. Control (no stretching) resulted in greater (P<0.05) cooking loss, but there was significantly less purge loss (P<0.05). The ratio 630/580 nm and a* colour values at 0 and 5 days decreased at a significantly (P<0.05) slower rate when SmartStretch™ was applied. Overall medium voltage stimulation did not inhibit the effectiveness of the SmartStretch™ treatment. The SmartStretch™ treatment provided significant improvement in tenderness and the potential to increase meat display time., (Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.)

This study examined the effect of palm, soybean or fish oils on the performance, muscle fatty acid composition and meat quality of goat kids. Twenty-four male Mahabadi kids (BW=19.4±1.2 kg) were divided into three groups according to liveweight and randomly allocated to one of three diets. Animals were fed ad libitum for 84 days. Different dietary fat sources had no effect on performance and/or carcass quality attributes. The soybean oil diet decreased 16:0 and 18:0 concentrations and increased 18:2 and 18:3 and the ratio of PUFA/SFA in the muscle compared with other treatments. Fish oil feeding increased 20:5 n-3 and 22:6 n-3 concentrations and decreased the ratio of n-6/n-3 in the muscle. The results demonstrate that the use of fish oil is a nutritional strategy to improve the health claimable long-chain omega-3 fatty acid content and n-6/n-3 ratio in goat meat without changing the sensory properties or colour of meat., (Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.)

This study evaluated the effect of SmartStretch™ technology and ageing on meat quality traits of hot-boned beef m. semimembranosus from cull cows. The technology uses a flexible rubber sleeve surrounded by inflatable bladders that are housed within an airtight chamber. The sleeve is expanded allowing the meat to be inserted. Air is then pumped into the inflatable bladders causing the meat to be compressed by force and ejected into packaging. No significant treatment effect (P>0.05) on shear force was found although ageing did significantly reduce shear force (P<0.001). There was a significantly greater (P<0.05) cook loss at 14 days, but less (P<0.05) thaw loss and purge with 0 day cook loss unaffected (P>0.05). Sarcomere length examined by both laser diffraction and a filar micrometre method was significantly increased (P<0.05) following the treatment although a proportion of individual myofibrils appeared to have short and long sarcomeres., (Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.)

This study evaluated the effect of stretching hot-boned sheep hindlegs from 40 sheep carcases, classified as mutton, using a prototype device (SmartStretch™). Left and right legs were collected pre-rigor and randomly allocated to one of four treatments; 0days ageing+SmartStretch™, 0days ageing+no stretch, 5days ageing+SmartStretch™ and 5days ageing+no stretch. There was a significant interaction between stretch treatment and ageing (P<0.05) for shear force of the m. biceps femoris such that stretched and aged samples were the most tender. By contrast stretched m. semimembranosus (SM) had a significantly (P<0.05) lower shear force only at 0days of ageing. Stretching produced longer sarcomeres (P<0.001) for both the SM and m. semitendinosus muscles. Myofibrillar degradation indicated by particle size analysis or histology was not affected by stretching, but there was an ageing effect (P<0.001). SmartStretch™ provided significant improvements in tenderness of the individual muscles., (Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.)

This study evaluated the effect of stretching hot-boned sheep topsides using a pre-production prototype device (SmartStretch™). To test this effect, 40 sheep from 3 consignments were assessed. Left and right topsides were collected pre-rigour and randomly allocated to one of four treatments; 0 days ageing+SmartStretch™, 0 days ageing+no stretch, 5 days ageing+SmartStretch™ and 5 days ageing+no stretch. Meat from the 0 days aged+no stretch treatment was the least tender and the 5 days ageing+SmartStretch™ treatment resulted in the most tender meat. The m. semimembranosus from topsides stretched using the SmartStretch™ prototype device had a lower cooking loss percentage (P<0.001) and longer sarcomeres (P<0.001) than non-stretched m. semimembranosus. There was no effect of SmartStretch™ on myofibrillar degradation measured using particle size analysis (PSA), but there was an ageing effect (P<0.001). The tenderness of stretched m. semimembranosus showed significant improvement over non-stretched m. semimembranosus., (Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.)

The temperature when the pH=6.0 (temp@pH6) impacts on the tenderness and eating quality of sheep meat. Due to the expense, sarcomere length is not routinely measured as a variable to explain variation in shear force, but whether measures such as temp@pH6 are as useful a parameter needs to be established. Measures of rigor onset in 261 carcases, including the temp@pH6, were evaluated in this study for their ability to explain some of the variation in shear force. The results show that for 1 day aged product combinations of the temp@pH6, the pH at 18 °C and the pH at 24 h provided a larger reduction (almost double) in total shear force variation than sarcomere length alone, with pH at 24 h being the single best measure. For 5 day aged product, pH at 18 °C was the single best measure. Inclusion of sarcomere length did represent some improvement, but the marginal increase would not be cost effective., (Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.)

The effectiveness of a kiwi fruit based solution for improving the tenderness of beef m. semimembranosus and the effect on colour stability was studied. Three treatments were applied; (1) injection with the solution, (2) injection with water and (3) no injection. All samples were packaged using a SmartShape™ prototype and aged for 1 or 14 days. There was a significant effect (P<0.001) of the kiwi fruit solution on shear force, with no difference between samples injected with water and those not injected. For compression of the samples no fixed effects were significant (P>0.05). Samples not injected (control) were the darkest (lowest L* values) with no difference between samples injected with water and those injected with kiwi fruit solution. Injected samples had lower a* (redness) values than non-injected samples. In general the samples not injected had higher ratio (630/580 nm) values indicating less formation of metmyoglobin., (Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.)

Given the lack of data that relates consumer acceptance of lamb colour to instrument measures a study was undertaken to establish the acceptability thresholds for fresh and displayed meat. Consumers (n=541) were asked to score 20 samples of lamb loin (m.longissimus thoracis et lumborum; LL) on an ordinal scale of 1 (very acceptable) to 5 (very unacceptable). A sample was considered acceptable by a consumer if it scored three or less. Ten samples were used for testing consumer response to fresh colour and 10 to test consumer response to colour during display of up to 4days. The colour of fresh meat was measured using a Minolta chromameter with a closed cone and a Hunter Lab Miniscan was used for measuring meat on display. For fresh meat when the a( *) (redness) and L( *) (lightness) values are equal to or exceed 9.5 and 34, respectively, on average consumers will consider the meat colour acceptable. However a( *) and L( *) values must be much higher (14.5 and 44, respectively) to have 95% confidence that a randomly selected consumer will consider a sample acceptable. For aged meat, when the wavelength ratio (630/580nm) and the a( *) values are equal to or greater than 3.3 and 14.8, respectively, on average consumers will consider the meat acceptable. These thresholds need to be increased to 6.8 for ratio (630/580nm) and 21.7 for a( *) to be 95% confident that a randomly selected consumer will consider a sample acceptable., (Crown Copyright 2010. Published by Elsevier Ltd. All rights reserved.)

In May of 2008, samples of southern highbush blueberry (interspecific Vaccinium corymbosum hybrids) exhibiting marginal leaf necrosis were collected at a farm in Interlachen, FL. The cv. Star showed severe leaf scorch, partial defoliation, and a generally unthrifty growth structure of many thin twigs as has been observed in Georgia (1). The block of Star plants was approximately 10 years old and incidence of the disease was 100%. The grower reported the planting had become increasingly unproductive in the most recent 4 to 5 years. Plants of the cv. Windsor also showed scorch symptoms and yellow-to-red discoloration of leaves. Proportionally fewer Windsor plants showed disease symptoms than Star plants and the disease was not as severe on this cultivar on the basis of visual estimates at the time. Each sample consisted of 5 to 10 cuttings of spring wood with attached leaves showing marginal necrosis taken from a single plant. Three samples, two from Star plants and one from a Windsor plant, were divided into two subsamples each. One subsample was submitted to Agdia for Xylella fastidiosa double-antibody sandwich (DAS)-ELISA assay (TSE XF; Agdia Inc., Elkhart IN). All three samples were reported as positive for X. fastidiosa by DAS-ELISA. A number of asymptomatic plants from this farm and other additional farms were tested in the same manner and results were negative. The other subsample was used for isolation of the causal bacterium. Petioles and main veins from symptomatic leaves were surface disinfested in 1% sodium hypochlorite, cut into segments (0.5 cm), and squeezed with forceps or pliers. Sap that exuded from the segment was blotted directly onto periwinkle wilt medium (2). Bacterial colonies consistent in morphology with X. fastidiosa that were DAS-ELISA positive were obtained from all three samples. One isolate from each sample was inoculated into four Star plants each with the pin-pricking method (3). Leaf scorch symptoms were first observed 8 weeks after inoculation. By 12 weeks after inoculation, all plants inoculated with the three isolates had developed symptoms, including defoliation. Plants inoculated without bacteria showed no symptoms. X. fastidiosa was reisolated from symptomatic plants. Bacterial leaf scorch is an important emerging disease that threatens the southern highbush blueberry industry in the south. On certain cultivars like Star, the potential to reduce yield appears to be great. Differences between cultivars are likely, but have not yet been explored. Additional research is needed into the epidemiology of the disease and potential vectors of pathogen transmission. References: (1) C. Chang et al. HortScience 44:413, 2009. (2) M. Davis et al. Curr. Microbiol. 6:309, 1981. (3) D. L. Hopkins et al. Phytopathology 75:713, 1985.

This study examined the level of long chain omega-3 and omega-6 polyunsaturated fats, the ratio of polyunsaturated fat to saturated fat (PUFA/SFA) and the ratio of omega-6 to omega-3 (n-6/n-3) fat in sheep grown under grazing conditions in Australia. The sheep genotypes used were Poll Dorset(growth)×Border Leicester Merino (PDg×BLM), Poll Dorset(growth)×Merino (PDg×M), Poll Dorset(muscling)×Merino (PDm×M), Border Leicester×Merino (BL×M) and Merino×Merino (M×M). Loin muscles (Longissimus lumborum) collected from 40 ewe and wether sheep slaughtered at 14months of age were processed for fatty acid determination. After frozen storage, 20g samples were minced and a 7g homogenate was processed for muscle lipid extraction using a chloroform:methanol (2:1) procedure. There was an increase in PUFA/SFA as the proportion of Merino genetics increased in the progeny (second-cross

The impact of homogenization speed on Particle Size (PS) results was examined using samples from the M.longissimus thoracis et lumborum (LL) of 40 lambs. One gram duplicate samples from meat aged for 1 and 5days were homogenized at five different speeds; 11,000, 13,000, 16,000, 19,000 and 22,000rpm. In addition to this LL samples from 30 different lamb carcases also aged for 1 and 5days were used to study the comparison between PS and myofibrillar fragmentation index (MFI) values. In this case, 1g duplicate samples (n=30) were homogenized at 16,000rpm and the other half (0.5g samples) at 11,000rpm (n=30). The homogenates were then subjected to respective combinations of treatments which included either PS analysis or the determination of MFI, both with or without three cycles of centrifugation. All 140 samples of LL included 65g blocks for subsequent shear force (SF) testing. Homogenization at 16,000rpm provided the greatest ability to detect ageing differences for particle size between samples aged for 1 and 5days. Particle size at the 25% quantile provided the best result for detecting differences due to ageing. It was observed that as ageing increased the mean PS decreased and was significantly (P<0.001) less for 5days aged samples compared to 1day aged samples, while MFI values significantly increased (P<0.001) as ageing period increased. When comparing the PS and MFI methods it became apparent that, as opposed to the MFI method, there was a greater coefficient of variation for the PS method which warranted a quality assurance system. Given this requirement and examination of the mean, standard deviation and the 25% quantile for PS data it was concluded that three cycles of centrifugation were not necessary and this also applied to the MFI method. There were significant correlations (P<0.001) within the same lamb loin sample aged for a given period between mean MFI and mean PS (-0.53), mean MFI and mean SF (-0.38) and mean PS and mean SF (0.23). It was concluded that PS analysis offers significant potential for streamlining determination of myofibrillar degradation when samples are measured after homogenization at 16,000rpm with no centrifugation.

The use of alternating frequencies during stimulation can increase stimulation response of a medium voltage electrical stimulation unit (MVS) by increasing the rate of pH decline. Various combinations of frequency modulation were tested in experiment 1 to determine the treatment resulting in the greatest stimulation response; the lowest initial pH, fastest rate of pH decline, highest temperature at pH 6 and the highest number of carcasses with a pH of 6 by 25(o)C and the treatment achieving the highest number of carcasses in the pH temp window (temperature at pH 6 between 18-25(o)C). The objective meat quality of these treatments compared to an unstimulated treatment was tested in experiment 2. Modulating the frequency (Hz) across the 6 segmented electrodes of the MVS by 10, 15, 25, 10, 15, 25Hz (Treatment 6, using a pulse width: 2.5ms, current: 1A) resulted in the greatest stimulation response. This treatment may be suitable for abattoirs that hot bone sheepmeat and require fast pH declines to ensure minimal cold shortening of meat. However, this treatment did not result in the tenderer meat despite the higher stimulation response. This treatment may have induced a greater number of contractions overall and therefore a greater pH decline response but resulted in less myofibrillar disruption compared to the other treatments due to a concomitant decreased force of contraction thus reducing potential tenderisation. Maintaining a constant frequency of 15Hz (Treatment 1; pulse width: 2.5ms, current: 1A) resulted in a higher number of carcasses in the pH temp window required (temperature at pH 6 between 18-25(o)C) in part A (P<0.05) and in addition to the higher tenderness levels this treatment may be more appropriate to satisfy the overall demands of abattoirs using these systems. This paper has also demonstrated electrical stimulation results in tenderer meat compared to unstimulated meat even after 30d of ageing (2.53±0.4 compared to 2.85±0.1 for the loin (M. longissimus thoracis et lumborum) (P<0.01) possibly due to a protective benefit of stimulation on meat tenderness. Overall, no detrimental effects of modulating frequency were observed on drip loss or retail colour display despite a greater rate of colour change observed with the modulated frequency treatment and the longer aged product.

Genetic correlations between reproduction traits in ewes and carcass and meat quality traits in Merino rams were obtained using restricted maximum likelihood procedures. The carcass data were from 5870 Merino rams slaughtered at approximately 18 months of age that were the progeny of 543 sires from three research resource flocks over 7 years. The carcass traits included ultrasound scan fat and eye muscle depth (EMDUS) measured on live animals, dressing percentage and carcass tissue depth (at the GR site FATGR and C site FATC), eye muscle depth, width and area and the meat quality indicator traits of muscle final pH and colour (L*, a*, b*). The reproduction data consisted of 13 464 ewe joining records for number of lambs born and weaned and 9015 records for LS. The genetic correlations between reproduction and fat measurements were negative (range -0.06 +/- 0.12 to -0.37 +/- 0.12), with smaller correlations for live measurement than carcass traits. There were small favourable genetic correlations between reproduction traits and muscle depth in live rams (EMDUS, 0.10 +/- 0.12 to 0.20 +/- 0.12), although those with carcass muscle traits were close to zero. The reproduction traits were independent of meat colour L* (relative brightness), but tended to be favourably correlated with meat colour a* (relative redness, 0.12 +/- 0.17 to 0.19 +/- 0.16). There was a tendency for meat final pH to have small negative favourable genetic correlations with reproduction traits (0.05 +/- 0.11 to -0.17 +/- 0.12). This study indicates that there is no antagonism between reproduction traits and carcass and meat quality indicator traits, with scope for joint improvement of reproduction, carcass and meat quality traits in Merino sheep.

Previous work identified that a large number of domestic lamb carcases processed in Australia do not meet the recommended pH/temperature window during chilling. New medium voltage electrical stimulation technology has been developed to alleviate this problem. This study used an optimised setting (800mA with a pulse width 0.5ms) to evaluate the effects on meat quality with a focus on tenderness and meat colour. In total 40 (electrically stimulated) and 40 (non electrically stimulated) lambs from 11 lots killed over 2 days were evaluated. There was a significant difference (P<0.05) between stimulation treatments for initial pH, rate of pH decline and the predicted temperature at pH 6.0. There was also a large difference in the number of carcases that met the recommended window (pH of 6.0, between 18 and 25°C), with an average 67.5% of stimulated carcases and 25% of unstimulated carcases meeting or falling just above the recommended window. The stimulation treatment had no significant (P>0.05) effect on sarcomere length or myofibrillar fragmentation index (MFI) of the m. longissimus (LL). After 1day of ageing LL samples from stimulated carcases had a significantly lower (P<0.05) shear force than non stimulated samples, but there was no difference between stimulation treatments after 5 days ageing. However, ageing period did have a significant effect (P<0.001) on both MFI and shear force, such that 5days aged product had higher MFI and lower shear force values. There were minimal effects of stimulation on colour stability.

Genetic parameters for carcass and meat quality traits of about 18-month-old Merino rams (n = 5870), the progeny of 543 sires from three research resource flocks, were estimated. The estimates of heritability for hot carcass weight (HCW) and the various fat and muscle dimension measurements were moderate and ranged from 0.20 to 0.37. The brightness of meat (colour L*, 0.18 +/- 0.03 standard error) and meat pH (0.22 +/- 0.03) also had moderate estimates of heritability, although meat relative redness (colour a*, 0.10 +/- 0.03) and relative yellowness (colour b*, 0.10 +/- 0.03) were lower. Heritability estimates for live weights were moderate and ranged from 0.29 to 0.41 with significant permanent maternal environmental effects (0.13 to 0.10). The heritability estimates for the hogget wool traits were moderate to high and ranged from 0.27 to 0.60. The ultrasound measurements of fat depth (FATUS) and eye muscle depth (EMDUS) on live animals were highly genetically correlated with the corresponding carcass measurements (0.69 +/- 0.09 FATC and 0.77 +/- 0.07 EMD). Carcass tissue depth (FATGR) had moderate to low genetic correlations with carcass muscle measurements [0.18 +/- 0.10 EMD and 0.05 +/- 0.10 eye muscle area (EMA)], while those with FATC were negative. The genetic correlation between EMD and eye muscle width (EMW) was 0.41 +/- 0.08, while EMA was highly correlated with EMD (0.89 +/- 0.0) and EMW (0.78 +/- 0.04). The genetic correlations for muscle colour with muscle measurements were moderately negative, while those with fat measurements were close to zero. Meat pH was positively correlated with muscle measurements (0.14 to 0.17) and negatively correlated with fat measurements (-0.06 to -0.18). EMDUS also showed a similar pattern of correlations to EMD with meat quality indicator traits, although FATUS had positive correlations with these traits which were generally smaller than their standard error. The genetic correlations among the meat colour traits were high and positive while those with meat pH were high and negative, which were all in the favourable direction. Generally, phenotypic correlations were similar or slightly lower than the corresponding genetic correlations. There were generally small to moderate negative genetic correlations between clean fleece weight (CFW) and carcass fat traits while those with muscle traits were close to zero. As the Merino is already a relatively lean breed, this implies that particular attention should be given to this relationship in Merino breeding programmes to prevent the reduction of fat reserves as a correlated response to selection for increased fleece weight. The ultrasound scan traits generally showed a similar pattern to the corresponding carcass fat and muscle traits. There was a small unfavourable genetic correlation between CFW and meat pH (0.19 +/- 0.07).

Hot carcase weight (HCW) and the GR tissue depth (total tissue depth over the 12th rib, 110mm from the midline) were measured on 312 crossbred (Poll Dorset×Merino) lambs with a mean live weight of 47kg. At a position 30mm distal to the lumbar-sacral junction, the depth (RMD) of the rump muscles was measured along with subcutaneous fat depth overlaying the m. gluteus medius (RFD). The subcutaneous fat depth over the m. longissimus (loin) at the 12th rib was measured (Fat C), as was the depth and width of the loin cross section (EMD and EMW, respectively). The right side of each carcase was scanned by a dual energy X-ray bone densitometer and fat and lean weight determined and the percentage of lean and fat content in the carcases calculated. HCW alone accounted for 26% of the variation in percentage lean content (LC), with GR measurement being the single best predictor of LC (R(2)=48.1; r.s.d.=1.89). RFD provided a less accurate and precise estimate of LC (R(2)=37.3; r.s.d.=2.07) than either GR or Fat C (R(2)=46.5; r.s.d.=1.92). Inclusion of HCW with either GR or Fat C provided a small improvement in the amount of variation in LC which could be explained. The measurement of breeding animals by ultrasound includes the terms weight, Fat C and EMD. These predictors when combined explained 49% of the variation in LC whereas by comparison measures of weight, RFD and RMD only explained 42% of the variation in LC. The current method of measuring fat depth over the 12th/13th rib is practical and measurement over the rump does not present an advantage based on the results of this study.

The aim of this work was to establish consumer perceptions of the eating quality of commercially processed hot boned sheep meat. The eating quality scores for tenderness, flavour, juiciness, and overall liking of grilled m. longissimus thoracis et lumborum (LL) were derived from untrained consumers. The animals used in this experiment were sourced from three different properties and were of various ages, breed, and sex, and had been on various quality pastures. All carcases were subjected to immobilisation, spinal discharge and high voltage electrical stimulation and boned within 2h of slaughter. All LL samples were frozen after boning according to the system applied at the abattoir and samples kept for consumer assessment and measurement of meat quality. The results showed, on average carcases entered rigor at high temperatures with a pH of 5.95 at 29.3°C. With an average sarcomere length of 1.68μm, some shortening was evident and there was a significant difference between lots in sarcomere length (P<0.05). A large percentage (82%) of samples had a pH greater than 5.8 at the time of freezing. All samples taken for shear force analysis exceeded a recommended threshold for acceptable table meat of 49N and there was no significant difference between lots (P>0.05). Only 13.5% of the samples met the 'good everyday' requirement following sensory assessment and there were significant differences between lots for eating quality traits (P<0.05). This work clearly shows that the application of effective electrical stimulation is not sufficient to ensure that hot boned sheep meat will be suitable as a table meat. These findings highlight the need for the inclusion of other intervention techniques.

Naturally occurring strains of Xylella fastidiosa Wells et al. that were weakly virulent or aviru-lent to grapevine were inoculated into the lower internodes of Vitis vinifera L. cv. Carignane plants in the greenhouse and challenge inoculated with pathogenic strains 2 weeks later. Several strains provided some reduction in symptom development. Most effective in preventing or slowing the development of Pierce's disease in the greenhouse tests were a strain from sycamore and two from elderberry. In a 2-year test on 'Himrod' grape in the vineyard, strain Syc86-1 (from sycamore), but not strain PD-1 (from grapevine), was effective in limiting the development of Pierce's disease. In tests on new vineyard plantings of 'Flame Seedless' and 'Cabernet Sauvi-gnon', six strains of X. fastidiosa were evaluated for biological control of the natural progression of Pierce's disease. Only strain EB92-1 (from elderberry) provided good control of the disease in both Flame Seedless and Cabernet Sauvignon. Strain Syc86-1 was ineffective in these vineyard tests. Grape strain PD95-6 did lower disease severity in Flame Seedless when compared with nontreated vines, and grape strain PD91-2 delayed symptoms in Cabernet Sauvignon for 12 to 18 months. Biological control by inoculation of susceptible grapevines with benign strains of X. fastidiosa, especially strain EB92-1, appears to have the potential to control Pierce's disease in commercial vineyards in Florida and other areas where the disease occurs.

The myofibrillar fragmentation index (MFI) was determined by the turbidity method on five samples of ovine Longissimus muscle, aged for either 1 or 5 days and processed from the frozen state over 3 weeks. These samples were homogenized at one of four speeds (11,000, 16,000, 19,000 or 22,000 rpm) with a shaft type homogenizer (Ystral) and at 15,000 rpm with a blade type homogenizer (Omni mixer). At all speeds except 15,000 or 22,000 rpm samples were homogenized for either one or two bursts of 30 s giving a total of eight different treatments. There was a significant interaction between ageing and treatment (P<0.05) and ageing and muscle sample (P<0.001). Regarding the Omni mixer result as a reference standard, the closest result from the Ystral homogenizer was obtained at 19,000 rpm after two bursts of 30 s. These two treatments gave similar mean values for samples aged 5 days. Repeatability between duplicates did not differ significantly for the various treatments (r=0.55). A large difference was found between samples aged for 1 and 5 days and the difference was greater for the Ystral homogenizer than the Omni mixer. The Omni mixer values for 1 day aged samples were 38 units less than for samples aged for 5 days while this difference for the Ystral homogenizer was 63 units. As speed of homogenization increased with the Ystral homogenizer the overall mean values increased and the values were always greater after two bursts of 30 s compared to one burst of 30 s. The results suggest that the Ystral homogenizer may be better for detecting differences between treatments than the Omni mixer. At the slower speeds myofibrils consist of more sarcomeres and intermyofibril linkages could still be observed. This contrast was also seen between samples aged for 1 or 5 days with much greater degradation visually observed in the latter samples. This was supported by the quantitative data.

A wide selection of lamb types of mixed sex (ewes and wethers) were slaughtered at a commercial abattoir and during this process images of 360 carcasses were obtained online using the VIAScan® system developed by Meat and Livestock Australia. Soft tissue depth at the GR site (thickness of tissue over the 12th rib 110 mm from the midline) was measured by an abattoir employee using the AUS-MEAT sheep probe (PGR). Another measure of this thickness was taken in the chiller using a GR knife (NGR). Each carcass was subsequently broken down to a range of trimmed boneless retail cuts and the lean meat yield determined. The current industry model for predicting meat yield uses hot carcass weight (HCW) and tissue depth at the GR site. A low level of accuracy and precision was found when HCW and PGR were used to predict lean meat yield (R(2)=0.19, r.s.d.=2.80%), which could be improved markedly when PGR was replaced by NGR (R(2)=0.41, r.s.d.=2.39%). If the GR measures were replaced by 8 VIAScan® measures then greater prediction accuracy could be achieved (R(2)=0.52, r.s.d.=2.17%). A similar result was achieved when the model was based on principal components (PCs) computed from the 8 VIAScan® measures (R(2)=0.52, r.s.d.=2.17%). The use of PCs also improved the stability of the model compared to a regression model based on HCW and NGR. The transportability of the models was tested by randomly dividing the data set and comparing coefficients and the level of accuracy and precision. Those models based on PCs were superior to those based on regression. It is demonstrated that with the appropriate modeling the VIAScan® system offers a workable method for predicting lean meat yield automatically.

Prevention of seed transmission of Acidovorax avenae subsp. citrulli into the transplant house or field is the most effective control of bacterial fruit blotch of watermelon currently available. Peroxyacetic acid was evaluated as a disinfectant that might efficaciously eradicate A. avenae subsp. citrulli from contaminated seed and also be efficacious against other seed-transmitted diseases of watermelon. Peroxyacetic acid at low concentrations eliminated A. avenae subsp. citrulli, Fusarium oxysporum, and Didymella bryoniae from microbial suspensions. Treatments of seed contaminated with A. avenae subsp. citrulli and D. bryoniae with peroxyacetic acid at 1,600 μg/ml and higher for 30 min were effective in preventing seed transmission of bacterial fruit blotch and gummy stem blight. Hydrochloric acid treatments at 10,000 μg/ml, while effective in eliminating seed transmission to watermelon seedlings, can adversely affect seed germination, especially with triploid seed. Efficacious dosages of peroxyacetic acid can be applied safely to freshly harvested triploid watermelon seed without concerns for reduction in seed quality. A most effective wet seed treatment protocol involved a 30-min treatment with peroxyacetic acid at 1,600 μg/ml followed by seed drying at low humidity in a 40°C drying oven for 48 h.

Application of electrical stimulation in the sheep and beef processing industry has been erratic around the world and this may reflect an incomplete knowledge of how to optimise the technology. Although it is well established that stimulation increases the rate of post-mortem glycolysis, other biochemical and biophysical effects have been implicated with the use of this technology. This review seeks to examine the current theories about the effect of stimulation on post-mortem muscle. The classical view that stimulation prevents muscle from shortening excessively during rigor development has been expanded to include the possibility that it also results in physical disruption of muscle structure. The interaction of these effects with the acceleration of the rate of proteolysis through activation of the calpain protease system has not been comprehensively reviewed in the past. Thus there are two mechanisms which could explain the effect of stimulation on tenderisation, reduced 'cold-induced' shortening and alteration of protein structure. A secondary effect is the enhancement of the rate of proteolysis stimulated by release of Ca (2+) at a higher temperature. As a result of this review we highlight several areas that may prove fruitful for further research. The challenge for further development of electrical stimulation systems is optimisation of the activation of the enzyme systems in parallel with manipulation of chilling regimes so as to ensure rigor mortis is achieved at temperatures which minimise shortening. These optimal temperatures largely established at a fixed incubation temperature for detached muscle may be different when measured in intact carcasses. The potential of regional stimulation of sections of the carcass to achieve this outcome is worthy of study given the different fibre composition of muscles and temperature gradients. In addition, to ensure that appropriate amounts of energy are applied to individual carcasses, development of self-response stimulation units, which are able to determine carcass resistance and apply appropriate durations or strengths of stimulation is worthy of future research. This would lead to more effective electrical stimulation practices.

Fusarium wilt of watermelon, caused by Fusarium oxysporum f. sp. niveum, is a destructive disease that limits watermelon production in many areas of the world. The discovery of several pyrenomycetous ascomycetes occurring naturally in association with different formae speciales of F. oxysporum identified these fungi as potential biological control organisms for watermelon wilt. One such mycoparasitic isolate, identified as Sphaerodes retispora var. retispora, was chosen for biological control and ecological trials in the greenhouse. Four different methods to inoculate the mycoparasite were evaluated, three of which utilized the parasite encapsulated into sodium alginate pellets. The other method employed root-dipping plants with mycoparasite ascospore suspensions. Ecological factors also were investigated, including the ability of S. retispora var. retispora to colonize watermelon roots, and its ability to survive in soil over time and reduce propagules of F. oxysporum f. sp. niveum. In the biological control studies, the use of the mycoparasite significantly reduced plant mortality and increased dry weights of watermelon plants after being challenged with F. oxysporum f. sp. niveum, compared with pathogen-inoculated controls. It appears that the incorporation of the parasite into alginate pellets in the planting mix at seeding may be the most practical method for future field evaluations of transplant-grown vegetable crops. In the ecological studies, the mycoparasite was recovered from infested soil after 9 months, but was only isolated from watermelon roots when applied in the presence of F. oxysporum. S. retispora var. retispora had no effect on F. oxysporum f. sp. niveum propagules after being applied to soils in the greenhouse.