Monitoring on-line of extracellular gamma-amino-4-butyric acid using microdialysis coupled to immunosensor analysis.

A method is described for the measurement of gamma-amino-4-butyric acid (GABA) within a microdialysis probe using an antibody-linked assay. A monoclonal antibody for GABA provides the specificity of measurement and these antibodies are affixed on a working platinum electrode within the probe. Determination of bound GABA is performed via an indirect assessment of competitive ligand also bound, and conjugated to horseradish peroxidase which is activated and measured as current change.

Changes in lactic acid levels during thawing of lamb chops.

Loins from 20 lambs with an ultimate pH ranging from 5.5 to 6.4 were frozen and stored at -20 °C, then thawed at + 3 °C.

The effects of non-vacuum packaging systems on drip loss from chilled beef.

This study investigated drip loss in chilled beef (hot-boned m. longissimus lumborum (LL)) under conventional packaging systems, in which a vacuum is applied, and non-vacuum packaging systems. The use of vacuum during the packaging process (vacuum packaging, CO(2) atmosphere packaging) was associated with increased drip.

Effects of chopping time, meat source and storage temperature on the colour of New Zealand type fresh beef sausages.

The colour stability of finely chopped fresh sausages made from post-rigor, pre-rigor salt added (1.5% w/w) or pre-rigor no salt added beef mince was evaluated using a Hunter Miniscan (L (∗) a (∗) b (∗)) and sensory colour panel. Batters were chopped for various times and sausages stored at -1.

Influence of culture media on the recovery of psychrotrophic Clostridium spp. associated with the spoilage of vacuum-packed chilled meats.

This study was undertaken to determine the influence of culture media on the quantitative recovery of vegetative cells and spores of psychrotrophic Clostridium spp. associated with the spoilage of chilled meats. For recovery of vegetative cells and spores (presumptive counts), 24 h or 48 h broth cultures in Peptone Yeast Extract Glucose Starch (PYGS) broth were used; for spore counts, concentrated spore suspensions derived from 35-day cultures were used.

Efficacy of heat and ethanol spore treatments for the isolation of psychrotrophic Clostridium spp. associated with the spoilage of chilled vacuum-packed meats.

Psychrotrophic Clostridium spp. associated with chilled meat spoilage are difficult to isolate and culture. In this study the kinetics of heat and ethanol spore inactivation was determined as a first step towards optimising the recovery of psychrotrophic clostridial spores from meat and environmental samples.

Antilisterial Effects of a Sorbate-Nisin Combination In Vitro and on Packaged Beef at Refrigeration Temperature.

The antilisterial effects of a sorbate-nisin combination were assessed in vitro and on beef at refrigeration temperature. Three hemolytic pathogenic strains of Listeria monocytogenes , reference strain NCTC 7973, food strain L70, and clinical strain L94, were stored at 4°C in phosphate-buffered saline, pH 5.5, containing a combination of sorbate (0.

Post-mortem calpain-system kinetics in lamb: Effects of clenbuterol and preslaughter exercise.

The effect of dietary supplementation with clenbuterol for either 8 days or 55 days in lambs was studied. The 55-day treatment was combined with an immediate preslaughter exercise regime. The effect of these treatments on post-mortem calpain system activities, meat ageing and meat quality was studied.

Effect of NaCl, polydextrose, and storage conditions on the functional characteristics and microbial quality of pre- and post-rigor salted beef.

The functionality and microbial storage life of pre-rigor beef mince stored at -1.5 °C under vacuum or a saturated carbon dioxide atmosphere, or at -18 °C in polyethylene bags, was investigated. Salt (2% w w ) or salt plus the cryoprotectant Polydextrose(®) (2%/2.

Oxytocin and prolactin suppress cortisol responses to acute stress in both lactating and non-lactating sheep.

Cortisol response to stress appears to differ between lactating and non-lactating animals. Lactating (14 d post partum) and non-lactating sheep were fitted with probes so that drugs and hormones could be infused directly into the posterior pituitary and paraventricular nucleus of the hypothalamus. The animals were also fitted with instruments to allow monitoring of heart rate, body temperature and blood cortisol levels.

Acceptability and functional properties of restructured roast from frozen pre-rigor injected beef.

Restructured beef roasts, made to a standardized formulation, were prepared using the following types of meat that had been stored at - 18 °C for 5 or 10 weeks: grass-fed bull beef pre-rigor injected with a salt/phosphate brine; uninjected grass-fed bull beef; uninjected grain-fed beef; a 50:50 blend of pre-rigor injected grass-fed bull beef and grain-fed beef; and a 50:50 blend of uninjected grass-fed bull beef and grain-fed beef. After frozen storage, pre-rigor injected beef had a higher (p < 0.05) ultimate pH than uninjected beef .

Real-time measurements of corticosteroids in conscious animals using an antibody-based electrode.

An electrochemical immunosensor for real-time determination of corticosteroids, a group of steroidal hormones, is reported. The sensor measures competitive binding of endogenous corticosteroid and a corticosteroid-peroxidase conjugate with antibodies, immobilized on a platinum electrode, by monitoring of peroxidase activity. The electrode is encased within a dialysate membrane, which separates the electrode environment from the sampled fluid, allowing corticosteroid to equilibrate across the membrane.

Real-time extracellular measurement of neurotransmitters in conscious sheep.

Measurements of neurotransmitters in conscious animals have been restrictive in real-time. The use of specific enzymes within an amperometric probe, based upon a microdialysis membrane, may overcome some of these problems. I report the use of such a probe, with different perfusions of enzymes, to allow real-time measurement of glutamate, catecholamines and indoleamines, in conscious animals.

Effect of pH at time of salting on the functional properties of pre-rigor beef.

The functional properties of thawed pre-rigor beef that had been minced and salted or not salted when its pH value reached 6.8, 6.6, 6.

Escherichia coli O157:H7 in healthy dairy cows.

Faecal samples were taken from 371 cows originating from 55 dairy farms and slaughtered at one slaughterhouse; tonsils were taken from 215 of these animals. Escherichia coli 0157:H7 was found in the faeces of only two animals and was not found in any tonsils. The farm supplying the first positive cow detected at the slaughterhouse was visited 3 months later and 160 animals (80 cows and 80 heifers) were tested by rectal swabs; E.

Comparison of aerobic and anaerobic methods for the microbiological monitoring of chilled packaged meat during storage.

Aerobic and anaerobic plate counts were compared for routine monitoring of the microflora, dominated by lactic acid bacteria, developing on vacuum- and carbon dioxide-packaged raw meat during chilled storage. No statistical differences were observed between aerobic and anaerobic enumerations, made on plate count and blood agar plates, of the microflora developing on beef striploins packaged under vacuum or carbon dioxide during 14 weeks' storage at 0 degree C. With both techniques the spoilage microflora development differed between the two packaging regimes.

Differences in pathogenicity for chick embryos and growth kinetics at 37 degrees C between clinical and meat isolates of Listeria monocytogenes previously stored at 4 degrees C.

Fifteen clinical strains of Listeria monocytogenes (eight strains of serogroup 4 and seven strains of serogroup 1) and 15 meat isolates (all serogroup 1) were stored with no growth in phosphate-buffered saline (pH 7.0) at 4 degrees C for 4 weeks. Pathogenicity for 14 day old chick embryos and growth kinetics in brain heart infusion (BHI) broth at 37 degrees C of the strains were determined before and after storage.

Distribution and sources of microbial contamination on beef carcasses.

Three beef dressing lines of different capacity (160, 440 and 800 head d(-1)) were investigated with respect to contamination associated with carcass/hide and carcass/faeces contacts, the distribution of microbial contamination on carcasses and the antimicrobial efficacy of cold water carcass washes. Swab samples were taken from up to 17 sites for determination of Aerobic Plate Counts at 37 degrees C (APC 37 degrees C) and Escherichia coli enumeration using the Petrifilm procedure. The three beef dressing systems produced virtually identical patterns of microbial contamination.

Fat-borne volatiles and sheepmeat odour.

The effects of lamb age and diet on volatiles from fat are described. Rendered fat from ram lambs raised on ewe's milk then a corn-based diet was compared with that from lambs raised on milk and a pasture of grass/clover, six treatments in all. An additional treatment comprised very old ewes maintained on pasture.

Insufficient antilisterial capacity of low inoculum Lactobacillus cultures on long-term stored meats at 4 degrees C.

Two of the 210 lactobacilli strains isolated from chilled meats produced antilisterial bacteriocins: Lactobacillus sake 265 (Lb 265) and Lactobacillus casei 52 (Lb 52). Factors affecting antilisterial effectiveness of these and two other bacteriocin-producing (Bac+) strains (Lactobacillus sake 706, Lb 706; and Lactobacillus sake 148, Lb 148) at refrigeration temperature (4 degrees C) were studied in laboratory media and meat systems. At both 4 degrees C and 25 degrees C, these Bac+ strains grown in buffered MRS broths (pH 5.

Effects of brine ingredients and temperature on cook yields and tenderness of pre-rigor processed roast beef.

In semimembranosus (SM) muscles removed pre- and post-rigor and injected 10% (wt/wt) with brines formulated to give 2% salt, 1.5% glucose, 0.3% phosphate, 0.

Effect of post-slaughter processing and freezing on the functionality of hot-boned meat from young bull.

The effects of variation in the times of mincing post mortem (2, 4, or 6 h), pre-rigor salting (1.5% wt wt ) and freezing rate [fast (10 min, liquid nitrogen); medium (4-6 h at -40 °C and 0.8 m s(-1) air velocity); or slow (36-38 h at -10 °C and 0.

Social behaviour in sheep relates to behaviour and neurotransmitter responses to nociceptive stimuli.

Sheep in the field display differences in social behaviour. These differences allow a division into three social groups with distinct behavioural occurrences and frequencies. The behavioural and neurotransmission responses of each of these groups to aversive stimuli were compared.