The effects of antifreeze proteins on chilled and frozen meat.

The effects of cryoprotectant proteins, trivially termed 'antifreeze proteins', from the Antarctic Cod and the Winter Flounder were assessed in meat during chilling and freezing. In light-microscopy studies, bovine muscle (Sternomandibularis) samples were soaked in phosphate buffered saline with and without 0·1 mg/ml antifreeze protein. Samples were then held frozen (-20°C) or chilled (2°C) for 3 days.

Pyridinoline in ovine intramuscular collagen.

Pyridinoline, a mature crosslink of collagen, was measured in intramuscular connective tissue isolated from ovine semimembranosus, a muscle noted for its highly insoluble collagen. Concentration ranged between 0·25 and 0·59 mol/mol of collagen, on the high side of concentrations reported in the literature for this and other muscles in various species. Pyridinoline concentration was inversely related to collagen solubility in muscle homogenates (P < 0·0).

Growth of Listeria monocytogenes, Aeromonas hydrophila and Yersinia enterocolitica in pâté and a comparison with predictive models.

A reference or type strain and a food derived-strain of the cold-tolerant pathogens Listeria monocytogenes, Aeromonas hydrophila and Yersinia enterocolitica were individually inoculated into samples of commercial pâté and incubated at 4 and 10 degrees C. The organisms were periodically estimated by presumptive counts, then values for the lag and generation times were calculated. Both strains of L.

The establishment of provisional quality assurance guidelines for assessing the hygienic adequacy of the lamb carcass cooling process.

The hygienic consequence of a lamb carcass cooling process can be assessed by evaluating the product's time-temperature history at a site within the carcass cavity adjacent to the 5th and 6th lumbar vertebrae. From these data, a numerical value, the process hygiene index, is generated which reflects the amount of potential bacterial growth the process allows and is proposed as an alternative quality assurance tool for assessing lamb cooling processes. Two hygienically acceptable lamb cooling processes, one producing carcasses destined for freezing and the other producing carcasses destined for chilled processing, were monitored.

Presence and coincidence of Listeria spp., motile aeromonads and Yersinia enterocolitica in a cold-smoked salmon processing and packing plant.

Environmental samples and samples of partially processed fish from a cold-smoked salmon processing and packing plant, and product samples purchased from retail outlets, were examined for the presence of Listeria monocytogenes and other Listeria spp., motile aeromonads and Yersinia enterocolitica. Listeria spp.

Construction and comparison of response surface kinetic models for the Yersinia enterocolitica type strain and a food isolate under aerobic conditions.

Response surface models were constructed for the type strain of Yersinia enterocolitica (ATCC 9610) and a wild type strain isolated from sliced roast lamb, for various conditions of temperature, pH, sodium chloride concentration and sodium nitrite concentration. Both strains grew at similar rates except at the 'extremes' of the conditions tested. Models for both quadratic and cubic polynomial equations are shown.

Quality control of bacterial enumeration.

Standard bacterial suspensions can be used to assess test method performance, via control charts, and inhibition of recovery when analyzing water samples. Variability in standard suspensions prepared from different strains and species and the use of frozen environmental samples for quality control for spore and bacteriophage analyses are also discussed.

The effect of preheated tendon as a lean meat replacement on the properties of fine emulsion sausages.

Tendon from beef hind leg muscles was used to replace some of the lean in a conventional emulsion formulation. The tendon was homogenized and either used raw or preheated for 2·5 h at a range of temperatures (50, 60, 70, 80°C) before use. Texture analysis and sensory evaluation were performed on cylinders of cooked sausage.

Tenderness of ovine semimembranosus: Is collagen concentration or solubility the critical factor?

The concentration and heat-dependent solubility of collagen were measured in the semimembranosus (36 animals) and, for comparison, the gluteus (108) muscles of sheep aged 4 months to 5 years. For both muscles, solubility declined with age but concentration remained unchanged. Compared to gluteus and other major ovine muscles, the semimembranosus had markedly insoluble collagen at a relatively low concentration.

The effects of antioxidative treatments on mutton flavour/odour intensity and species flavour differentiation.

This study examined the effects of curing and oxygen exclusion on the odour and flavour of sheepmeats. One series of experiments examined the effect of curing on the ability of panellists to distinguish between the flavours of lean mince from various species (mutton, beef, pork, chicken). Other experiments examined the effects of curing and of maintaining an anoxic storage/cooking environment on the intensity of mutton flavour and odour, particularly adipose tissue odour.

The effect of growth rate and ultimate pH on meat quality of lambs.

Entire male Romney lambs (n = 60) were grown slowly (67 g/day) and slaughtered at 14 months of age at an anticipated carcass weight of 18 kg. Another group of ram lambs (n = 15) from the same genetic background (born 7 months later) were grown rapidly (162 g/day) for 7 months and slaughtered at the same time and at a similar carcass weight. Preslaughter shearing (20 days prior to slaughter) and swim washing (3 times) were variously imposed upon the 14-month old lambs to give them a graded preslaughter stress.

Effect of residual oxygen on the colour, odour and taste of carbon dioxide-packaged beef, lamb and pork during short term storage at chill temperatures.

Samples of boneless pork, lamb, beef (high and normal pH) were packaged in '100%' carbon dioxide atmospheres in foil laminate pouches. These pouches were fitted with a septum and a gas sampling port that allowed the introduction of air and removal of gas samples for analysis from the sealed packs. After sealing, measured volumes of air were introduced into test packs that had been gassed at a carbon dioxide volume to meat weight ratio of either 1 litre/kg or 2 litres/kg, to give initial atmospheres containing approximately 0·1, 0·2 and 1·0% oxygen.

Construction of and Comparisons Between Response Surface Models for Aeromonas hydrophila ATCC 7966 and a Food Isolate Under Aerobic Conditions.

Response surface models were constructed for two strains of Aeromonas hydrophila , one the type strain (ATCC 7966) and the other isolated from chilled cooked mussels, for various conditions of temperature, pH, and NaCl concentration. The food-derived strain was found to be better adapted to growth at low temperatures than the type strain. Comparisons between the two strains and with the published model for strain K144, a clinical isolate, showed that the three strains differed in their predicted generation and lag times at refrigeration (5°C) and close to optimum (28°C) temperatures.

Incidence and coincidence of Listeria spp., motile aeromonads and Yersinia enterocolitica on ready-to-eat fleshfoods.

A survey for the presence of Listeria spp., Yersinia enterocolitica and motile aeromonads in 203 samples of ready-to-eat fleshfoods purchased from retail outlets was conducted. Overall, 39.

Variation in growth kinetics and phenotype of Aeromonas spp. from clinical, meat processing and fleshfood sources.

Sixty-four strains of motile aeromonads (A. hydrophila, A. sobria and A.

Onset of insensibility at slaughter in calves: effects of electroplectic seizure and exsanguination on spontaneous electrocortical activity and indices of cerebral metabolism.

Cerebral venous and femoral arterial blood samples were collected from 21 young calves either during electrical stunning and recovery or electrical stunning and slaughter by carotid severance or slaughter without stunning. The blood samples were analysed for PO2, PCO2, pH, glucose and lactate. The results were compared with simultaneous recordings of spontaneous electrocortical (ECOG) activity.

Thermal scanning rheology of myofibrillar proteins from muscles of defined fibre type.

Emulsion meat products are made with little regard to rheological properties of different muscles. Here the rheology of gels made from three classes of muscle defined by myosin type (fast twitch, slow twitch and heart) are compared. Myofibrillar fractions were prepared from representative bovine muscles-cutaneus trunci, masseter and heart-by a procedure that removed connective tissue, fat and sarcoplasmic proteins.

Effect of animal sex and size on effort when pelting lambs.

Pelting load data were collected and analysed for 304 lambs (comprising 46% ewes, 26% cryptorchids and 28% rams), all of which came from one farm. Although typically about 24% more impulse (Ns) had to be applied for pelting ram lambs than for ewe or cryptorchid lambs, only one-third of this increase was attributable to the distinct sexual category of rams; the rest was due to rams being heavier. Carcass size had a much greater effect on pelting load than animal sex: a change in dressed carcass weight of slightly less than 1 kg has the same effect on impulse requirement as the net sex effect.

Contribution of amino acid transmitters to epileptiform activity and reflex suppression in electrically head stunned sheep.

In sheep, administration of a combination of zolazepam and tiletamine hydrochloride resulted in a dose dependent reduction in the duration of epileptic activity induced by an electric stun applied to the head. The compound also lengthened the normal period of reflex suppression that occurs after a stun. Excitatory amino acid receptor antagonists (2-amino-7-phosphonoheptanoic and 2-amino-5-phosphonovaleric acids) also reduced the duration of epileptic activity following an electric stun.

Electroencephalograms and electrocardiograms in young bulls following upper cervical vertebrae-to-brisket stunning.

Passing an electric current (50 Hz, 400 V open circuit, current limited to 1.5 A) from two electrodes acting as a common single electrode set applied on each side of the dorsal surface of the neck (cervical vertebrae C2 to C5 region) to another placed on the brisket of young bulls causes fibrillation of the cardiac muscle, does not induce epileptiform changes in the electroencephalogram, and produces a state of body rigidity. Passing the same electric current through the same neck electrodes, now acting as two separate electrodes, without the brisket electrode, does induce epileptiform activity similar to that seen with head-only stunning, does not fibrillate the heart, and produces a state of limb rigidity lasting for some time after the stun.

Incidence of Motile Aeromonads in New Zealand Retail Foods.

A total of 396 food samples (ready-to-eat meat and poultry products; shellfish and finfish products; some raw shell and finfish and meat products; salads and coleslaws; baked confectionary) was purchased from local retail outlets and examined for the presence of motile aeromonads. Of the food categories tested, shellfish had the highest incidence, with 66% positive. Vegetable products, luncheon meat, salami, paté, and poultry products had very low incidences, and no motile aeromonads were found in baked confectionary, some of which contained whipped cream.

Growth of Escherichia coli and Salmonella typhimurium on high-pH beef packed under vacuum or carbon dioxide.

A strain each of Escherichia coli and Salmonella typhimurium, were inoculated onto samples of high-pH (greater than 6.0) beef. Samples were packaged under vacuum or CO2 and stored at 8, 10, 12, 15, 20 or 30 degrees C.

The effects of electrical stimulation, thawing, ageing and packaging on the colour and display life of lamb chops.

Electrical stimulation, freezing and thawing, ageing and type of packaging used during ageing are factors which could influence the final colour of meat. The experiment reported here determined the individual and additive effects of these factors in displayed lamb. Initial panel scores for colour of chops were increased by electrical stimulation and decreased by thawing and by ageing for up to six weeks.

The storage life of chicken carcasses packaged under carbon dioxide.

Broiler chicken carcasses were packaged under vacuum in film of low oxygen transmission rate, or under CO2 in gas-impermeable aluminum foil laminate. The packaged carcasses were stored at +3 or -1.5 degrees C.

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.