Effect of tray liners on the drip loss of lamb chops during retail display.

The amount of drip lost by lamb chops during display was affected by the type of tray liner used. In one study involving chilled and frozen/thawed meat, the use of an absorbent paper liner increased the drip loss and influenced whether or not the quantity of drip was affected by freezing/thawing. In another study, thawed chops held for 24 h on plastic coated trays without liner or on a plastic coated liner had less than 2% drip loss, whereas adjacent chops from the same loin processed and held in the same way but displayed on liners of absorbent paper or paper pouches of diatomaceous earth lost 4·3% and 5·6% drip, respectively. This effect of the material in contact with the meat should be considered when reporting drip loss data and when comparing results with those of other researchers.

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. Cuts wrapped in oxygen permeable film had better colour retention during storage and display. Storage of the frozen chops reduced the display life, with the largest effect occurring during the first 4-5 weeks' storage. Cuts stored at -10°C had no display life after 10 weeks' storage, whereas cuts stored at -20 and -35°C had some acceptable display life even after the longest storage period tested. Rib chops in general had better colour stability than loin 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. Initially there were no differences in Hunter L values (brightness) due to treatment, but chilled chops or those frozen for 1 day showed a greater increase in L values by the second day than those frozen for 7 weeks, after which there was no change in brightness. Hunter a values (redness) were higher in chilled chops and those thawed after 1 day's frozen storage than those frozen for 7 weeks before thawing. Hunter b values (yellowness) were greater at all times in chilled chops held for 7 weeks and varied amongst the other treatments. The measured per cent drip from chops frozen for only 1 day was greater on thawing than drip from chops frozen for 7 weeks before thawing. Drip during display, assessed by a sensory panel, increased more in those chops stored either chilled or frozen for 7 weeks before display.

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. Loins were removed from recently frozen carcasses and stored for 0, 10, 20 or 30 weeks at temperatures of -5°C, -10°C and -20°C. Chops were cut from the stored loins, packaged in oxygen permeable film, stored in the dark at -20°C for 0,4,8 or 12 weeks and then displayed at -20°C under continuous lighting. The retail display life of the chops was assessed by an experienced colour panel. The most rapid colour deterioration occurred in chops cut from unstored frozen loins and held for 12 weeks prior to display (display life of less than 1 day). Chops cut from loins stored for 30 weeks at -20°C, and then held for 12 weeks prior to display had a display life of 23 days. Both increased loin storage temperature and an increased duration of chop storage before display decreased the retial display life. This study indicates that frozen storage of cut chops for as little as 4 weeks reduces the display life by almost 80% so that whole carcasses or loins rather than cut chops should be shipped to distant markets. unstored frozen loins and held for 12 weeks prior to display (display life of less.

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. Display time affected brightness and hue in a linear manner.

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. Chops from loins which had been aged in vacuum pack had higher initial scores than those aged in oxygen-permeable film. Hunter colour values for chops from stimulated carcasses were much less variable than those for chops from unstimulated carcasses. Stimulation, therefore, produced a more uniform product. Hunter L, a and b values all declined during display, the greatest decline being in a (redness). Hunter values were not good predictors of initial panel scores but Hunter a and hue (a b ) both declined with panel scores. With no ageing, the display life of stimulated chilled lamb was longer than that of unstimulated lamb, but this advantage disappeared after ageing for 2 weeks in a vacuum pack. The display life of thawed unstimulated lamb was only slightly inferior to that of chilled unstimulated lamb when both were vacuum-packed, but thawed stimulated lamb resulted in a much reduced display life. Ageing of loins in oxygen-permeable film adversely affected display life of chops. Total drip loss from rigor to the end of display was significantly affected by all treatments except stimulation. The dominant cause of drip loss was the freeze-thaw treatment. In chilled and thawed lamb, ageing increased drip. Packaging had a lesser effect on drip.

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. During thawing, muscle (m. longissimus lumborum) lactate was measured in samples taken when the meat temperature reached -20, -5, -2, 0, and + 2 °C. At -5 °C, muscle lactate concentration was similar to that at -20 °C, but at -2 °C lactate levels were double those at -20 °C. As the temperature increased to +2 °C lactate concentrations fell from their -2 °C level. Low pH (5.5-5.6) and intermediate pH (5.7-6.1) meat at +2 °C had a higher lactate level than at -20 °C, with the greatest difference occurring in the low pH group (5 mmol lactate kg equating to approximately 0.05 pH unit increase). High pH meat (6.2-6.3) had similar lactate levels at -20 °C and +2 °C. These results demonstrate the importance of measuring the pH of frozen meat immediately rather than thawing the meat before measurement, and also show that meat pH may change on thawing, depending on the ultimate pH of the sample.

Sleep EEG effects of exercise with and without additional body cooling.

The aim of the study was to help clarify the equivocal findings with slow wave sleep (SWS) stages 3 and 4, following running in physically trained individuals. Six females (22-24 years) ran at 75% of their VO2max for 2 X 40 min periods on two separate occasions, 14.30-17.30 h: once under hot conditions, causing a rectal temperature (Tr) increase averaging 2.3 degrees C, and once with additional cooling, reducing the Tr rise to an average of 1.0 degree C. Compared with baseline nights, no significant sleep effects were found on the cool run. However, after the hot run, SWS, particularly stage 4 sleep, showed significant increases, and REM sleep was decreased. It was concluded that body heating effects during running may play a key role in SWS changes, and that additional cooling seems to eliminate any potential SWS increase.

Interviewing skills: a comprehensive approach to teaching and evaluation.

Evaluation procedures utilizing standardized interviews scored by means of a formal objective rating system which make it possible to measure the interviewing skills of health professional students have been developed in recent years. These procedures have been used in the Child Health Associate Program at the University of Colorado Medical School to evaluate the ability of a group of students to achieve the objectives of a practice-oriented interviewing course. Results from the standardized interviews indicate that students taking the course gathered an average of 76 percent of all available data and used 86 percent of the process skills defined as necessary for positive interview interaction. A previous group of child health associate students who did not take the course gathered an average of 47 percent of all available data and used an average of 62 percent of the necessary process skills.