Increase in retail display of frozen lamb chops with increased loin storage time before cutting into chops.

There is a steady deterioration of the colour of lamb chops during frozen storage. Storing meat in carcass form or as primals before cutting and packaging minimizes the exposure of the meat surfaces to deteriorating environmental effects. This experiment examines the effects of storage conditions (form, time and temperature) on the display life of frozen chops.

Thawing of lamb loin chops in air and CO(2). Effect on colour and drip.

Colour retention and drip loss was assessed during retail display for chilled lamb chops displayed fresh or stored in CO(2) for 7 weeks before display, and for chops frozen for various times and thawed in air or CO(2). A sensory panel found fresh lamb chops to have an acceptable display life of 1 day, while chops which had been frozen for 1 day and then thawed lasted 2 days. Holding chops for 7 weeks in a CO(2) atmosphere at - 1·5°C improved display life to 3 days, but frozen chops held for 7 weeks before thawing had deteriorated in colour, and only one group was acceptable on the initial day of display.

Comparison of EEG and ECoG for detecting cerebrocortical activity during slaughter of calves.

Parallel electrocorticograms (ECoG) and electroencephalograms (EEG) were recorded during stun-recovery and stun-slaughter of eight calves 4-6 weeks old. Epochs of 8·2 s duration, derived from the ECoG and EEG signals pre-stun, during recovery and during exsanguination, were compared for differences in power content and frequency distribution using Fast Fourier Transform analysis. ECoG signals recorded during the quiescent phase post-stun had a markedly lower power content compared with pre-stun, whereas the EEG signal showed no such reduction in power content.

Factors influencing frozen display life of lamb chops and steaks: Effect of packaging and temperature.

Frozen lamb loin and rib chops and leg steaks were wrapped in film of high oxygen permeability or vacuum packaged in film of low oxygen permeability and stored in the dark at -10, -20 or -35°C for periods from 0-20 weeks. After storage, the wrapped cuts were displayed in an open-top cabinet operating at -20°C under continuous fluorescent lighting (Philips Deluxe 32°). Cuts were evaluated by a trained colour panel to determine acceptable display life, and chop lean colour was evaluated using a Hunter colorimeter.

A possible role for myosin light chain 1 slow of bovine muscle.

Myosin light chain 1 slow (LC1slow) was purified from the bovine slow-twitch muscle masseter and used as an antigen in chicken. The antibody fraction from egg yolk was employed to show the distribution of LC1slow in samples of diverse bovine muscles. Adjacent cryosections were cut.

The storage life of chilled pork packaged under carbon dioxide.

Pork cuts of longissimus dorsi muscle with overlaying fat and skin were packed under vacuum in film of low oxygen transmission rate, or under CO(2) in gas impermeable aluminium foil laminate. Cuts were stored at +3 or -1·5°C. Vacuum packaged cuts were grossly spoiled by Brochothrix thermosphacta after 2 weeks' storage at 3°C and after 5 weeks at -1·5°C.

Effects of sugars on post-mortem glycolysis in bovine muscle mince.

Sternomandibularis muscles from steers were minced, within 75 min of slaughter, with sugars or amylases. The minces were held anoxically at 25°C for at least 7 h. At times samples were removed and chemically analysed.

Effect of packaging and display variables on retail display of frozen lamb chops.

Display conditions of packaging and lighting and the length of frozen storage of the carcass before cutting were examined for their effect on the colour of frozen chops during display. Lighting effected a greying and loss of saturation of the colour, while packaging film affected brightness and hue angle. Length of storage affected hue and saturation.

Jugular blood flow in calves after head-only electrical stunning and throat-cutting.

Jugular flow was measured after head-only electrical stunning and gash cutting in 12 calves less than a week old. Jugular flow was assumed to provide a crude measure of cerebral perfusion during exsanguination. In 10 animals the average amount of jugular blood collected within 1-2 min of throat-cutting was the equivalent of a total cerebral blood flow of 3·6 ml/min/100 g ± 1·4 SD or 4·8% of normal.

The solubility of carbon dioxide in meat.

The solubility of CO(2) in muscle tissue of pH 5·5 at 0°C was approximately 960 ml at STP/kg of tissue. The solubility increased with increasing tissue pH by 360 ml/kg for each pH unit. The solubility decreased with increasing temperature by 19 ml/kg for each °C rise.

The effect of the initial gas volume to meat weight ratio on the storage life of chilled beef packaged under carbon dioxide.

Normal pH (5·5-5·7) and high pH (>6·0) beef cuts of 400 g were vacuum packaged in polyvinylidine chloride (PVDC) laminate, in aluminium foil laminate or in foil laminate with a CO(2) scavenger (Ba(OH)(2)); or were packaged under CO(2) in foil laminate with CO(2) added at 200, 400, 700, 1000 or 2000 ml per kg of meat. The process used to prepare meat before packaging resulted in an initial flora containing a high fraction of eneterobacteria but with undetectable numbers of lactobacilli. During storage at +1°C, all vacuum packaged meat developed floras containing substantial fractions of enterobacteria.

Electroencephalographic studies of adult cattle associated with electrical stunning, throat cutting and carcass electro-immobilization.

Twelve adult cattle were electrically stunned head-only (400 V, 2.5 A, 50 Hz) behind the ears for four seconds. Within ten seconds of stun initiation, the carotid arteries, jugular veins, trachea and oesophagus were severed.

Packaging conditions for extended storage of chilled dark, firm, dry beef.

Normal-pH (5·5-5·7) and high-pH (> 6·0) beef cuts of 500g were vacuum packaged in polyvinylidene chloride (PVDC), metalized polyester or aluminium foil laminates, or in foil laminate packs inflated with 1 litre of CO(2). During storage at + 1°C. vacuum packaged cuts developed spoilage floras of lactobacilli and enterobacteria; cuts stored under CO(2) developed floras of lactobacilli alone.

The effect of electrical stunning and slaughter on the electroencephalogram of sheep and calves.

To study the application of electroencephalography (EEG) for the assessment of insensibility during stunning and slaughter, recordings were made on sheep that were slaughtered by throat cutting, electrically stunned head-only and allowed to recover, electrically stunned head-only followed by throat cutting or electrically stunned head-to-back. The same experiments were repeated on calves (1-6 weeks old) except some calves were stunned and allowed to recover before final stunning and throat cutting. After the throat cut, sheep became insensible (i.

Effect of zeranol on bull muscle fibre composition.

Two trials are reported in which bulls were implanted with zeranol and slaughtered at 18 months. There was no significant change in carcass weight due to zeranol in either trial. Samples of the longissimus dorsi (LD) and splenius (Sp) were cross-cryosectioned, stained for myofibrillar ATPase and examined by conventional light microscopy.

Modification of in-pack conditions to extend the storage life of vacuum packaged lamb.

High pH (>5·9) lamb loins from a research abattoir were subjected to differing packaging treatments to determine whether package modification could reliably extend the storage life of chilled lamb cuts beyond that attained by cuts vacuum-packaged in film of low gas permeability, as in current commercial practice. Treatments applied were carbon dioxide flushing or addition of a citrate buffer (pH 4·8), a 5% lactic acid solution or a Lactobacillus inoculum (plastic packs only) and packaging in a plastic film of moderately low oxygen permeability (140 cc/m(2)/24 h at 25°C and 90% relative humidity) or in a foil laminate of immeasurably low oxygen permeability. After 12 weeks' storage at -0.

Development of a Yeast Microflora on Frozen Lamb Stored at -5°C.

Lamb loins wrapped in gas-permeable plastic film and stored at -5°C developed a yeast microflora with maximum numbers (approximately 10/cm) being reached after 20 weeks of storage. Yeast isolates were identified as Cryptococcus laurentii var. laurentii , Cryptococcus infirmo-miniatus , Trichosporon pullulans and Candida zeylanoides .

Hamburgers and Broiler Chickens as Potential Sources of Human Campylobacter Enteritis.

Freezing to -18°C for 7 d reduced numbers of Campylobacter jejuni in artificially contaminated hamburgers by one log cycle. Minimal cooking rapidly eliminated the organism. No Campylobacters were detected in 50 samples of commercial ground meat.

Responses of different types of ox muscle to electrical stimulation.

The effects of electrical stimulation on fall in pH upon stimulation (ΔpH), rate of pH fall (dpH/dt at 35°C, cold shortening and muscle ultrastructure were investigated for the Cutaneus trunci (predominantly fast-twitch glycolytic fibres), the Masseter and Diaphragm (predominantly slow-twitch oxidative fibres) and the Sternomandibularis and Longissimus dorsi (bot fast- and slow-twitch fibres) of the ox. The Masseter and Diaphragm showed a small ΔpH and no increase in dpH/dt upon stimulation. Stimulation produced supercontracture but no tearing of the fibres throughout all of the Masseter.

Differential effects of electrical stunning on the early post-mortem glycolysis in sheep.

Electrical stunning methods have been examined to determine the effect on post-mortem glycolysis in various muscles of sheep. Although there was no effect on the ultimate pH achieved in any of the muscles, there were marked differences in the pH drop which occurred during stunning. When curare was used to block neuromuscular transmission much of the effect of stunning on glycolysis was removed.

Further studies on bovine muscle composition.

The average occurrences of fibre types, I,IIA and IIB in the longissimus dorsi (LD) of female cattle were 18%, 59% and 23%, respectively. The IIB occurrence lay between that for bulls and steers, reported in Young & Bass (1984). Since IIB fibres were absent from the splenius (Sp) of females, its composition was more akin to that of bulls than steers.

Effect of castration on bovine muscle composition.

Samples of bovine muscles were cross-sectioned and stained for myofibrillar ATPase. Three fibre types were distinguished, I, IIA and IIB. In the longissimus dorsi (LD) muscles of steers the average occurrence of IIB fibres was 32%, but in bulls was only 8%.

The biochemical basis of fibre types in bovine muscle.

Recent studies using isolated muscle fibres have established a link between the histochemical fibre types, I, IIA and IIB, which can be defined by myofibrillar ATPase activity, and three forms of myosin heavy chain. This work is reviewed, as is work on metabolic variability within these fibre types. Results are them presented which show that the activity of myofibrillar ATPase in sections, although principally determined by the myosin heavy chain, is modified by other myofibrillar components, as yet unidentified.

The shelf life of chilled sheep livers packed in closed tubs.

Livers incubated at 30°C in closed tubs developed floras dominated by Enterobacteriaceae. At chiller temperatures, floras were ultimately dominated by psychrotrophic lactobacilli. Tub-packed livers can have an extended shelf life similar to that reported for vacuum-packed liver.

Electrical stunning and stillness of lambs.

The stillness obtained with head-to-back stunning results from the current depolarizing spinal neurones. The same effect can be achieved by sequentially applying a head stun, followed by a current through the heart to stop it and a current down the spinal cord to abolish movement. The level of speckle bruising for this sequential stun is lower than that associated with head-to-back stunning and is similar to that of head-to-foreleg stunning.