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Detection of the site of contamination by Staphylococcus aureus within the defeathering machinery of a poultry processing plant 总被引:3,自引:2,他引:1
Counts of Staphylococcus aureus from samples of neck skin taken from poultry carcasses at different stages of processing showed that the numbers decreased approximately 10-fold during scalding but increased by almost 1000-fold during plucking, reaching up to 104 /g. Swab samples taken from the defeathering machinery yielded counts of ca. 103 /swab at the entry to the first plucker but these increased to ca. 107 at the exit, with a subsequent decrease through the second and third machines. Counts of other organisms growing on the Baird-Parker isolation medium showed much lower levels at the exit to the first plucker, suggesting that this was the major site of contamination at which S. aureus grew preferentially. Data obtained from four visits to the processing plant over a period of 10 months suggested that the incidence of S. aureus on the birds is affected by the season (summer or winter) whereas levels in the plucking machines depended on the day of sampling. 相似文献
3.
Development of captive bongos (Tragelaphus eurycerus): Activity budgets and developmental milestones
Debra L. Forthman Lorraine A. Perkins Joan I. Mead Nicolette S. Miller 《Zoo biology》1992,11(3):197-207
The development of changes in visual orientation, posture, activity budgets, and behavioral milestones was examined in five bongo calves which were observed from birth to 4 or 6 months of age. The only significant change in the calves' visual orientation was an increase in orientation to food. Reclining declined significantly over weeks, while standing increased and moving did not change. Overall, stationary behaviors dominated the activity budget, but decreased significantly over the study. The category that included locomotion, object exploration, and auto-play did not change, while forage and rumination increased significantly. Contrary to expectation, the decline in suckling was not significant. Affiliative interactions with the dam decreased significantly during the study, but increases in affiliation with other bongos were not significant. Levels of agonistic behavior between the calves and their dams and other herd members were low throughout the study, and did not change significantly. One female calf achieved several developmental milestones later than the others. It is suggested that these differences may have been influenced by the dominance status of her dam. The results conform to the general developmental pattern of “hider” bovids. Bongos, however, show somewhat different patterns of social development than eland, which are reported to be more precocial in expression of aggressive and sexual behaviors. © 1992 Wiley-Liss, Inc. 相似文献
4.
We measured the effective resistance (Reff) and elastance (Eeff) of the chest wall in four subjects, relaxed at functional residual capacity (FRC), during sinusoidal volume changes (5% vital capacity up to 4 Hz) delivered at the mouth. Subjects sat in a head-out body plethysmograph, and transthoracic pressure was measured with an esophageal balloon. Changes in Reff and in Eeff with frequency were nearly the same in all subjects. Reff (in cmH2O X l-1 X s) was 2.9 +/- 0.8 at 0.2 Hz and fell sharply to minimum values (0.5-0.9) at 1-4 Hz. Eeff (in cmH2O X l-1) increased from approximately 10 at the lowest frequency to a plateau of about 15 at 1-3 Hz and decreased above 3 Hz. In the same subjects, we measured the relative magnitude and phase between the displacements of different parts of the chest wall with magnetometers during identical sinusoidal forcing. Results indicate that the chest wall expands and deflates uniformly at frequencies up to 1 Hz. Thereafter the abdomen makes relatively larger excursions, and the relative magnitude and phase of displacement at different points on the chest wall show complex changes. We conclude that the frequency dependence of Reff and Eeff below 1 Hz is not due to nonuniformities in displacement of different parts of the chest wall. The frequency dependency of Reff is consistent with an increasing contribution of rate-independent plastic dissipation to the pressure difference in phase with flow as breathing frequency decreases. 相似文献
5.
The maximal expiratory-flow volume (MEFV) curve in normal subjects is thought to be relatively effort independent over most of the vital capacity (VC). We studied seven normal males and found positive effort dependence of maximal expiratory flow between 50 and 80% VC in five of them, as demonstrated by standard isovolume pressure-flow (IVPF) curves. We then attempted to distinguish the effects of chest wall conformational changes from possible mechanisms intrinsic to the lungs as an explanation for positive effort dependence. IVPF curves were repeated in four of the subjects who had demonstrated positive effort dependence. Transpulmonary pressure was varied by introducing varied resistances at the mouth but effort, as defined by pleural pressure, was maintained constant. By this method, chest wall conformation at a given volume would be expected to remain the same despite changing transpulmonary pressures. When these four subjects were retested in this way, no increases in flow with increasing transpulmonary pressure were found. In further studies, voluntarily altering the chest wall pattern of emptying (as defined by respiratory inductive plethysmography) did however alter maximal expiratory flows, with transpulmonary pressure maintained constant. We conclude that maximal expiratory flow can increase with effort over a larger portion of the vital capacity than is commonly recognized, and this effort dependence may be the result of changes in central airway mechanical properties that occur in relation to changes in chest wall shape during forced expiration. 相似文献
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Inhibition of enzyme activities by free fatty acids 总被引:9,自引:0,他引:9
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Partitioning of respiratory flow resistance in man 总被引:9,自引:0,他引:9
9.
Kinetic aspects of singing 总被引:1,自引:0,他引:1
10.
J. Hay W. Khan A.J.C. Mead D.V. Seal J.K. Sugden 《Letters in applied microbiology》1994,18(2):117-119
Commercially-available phenol red indicator, purified by adsorption chromatography was incorporated into lauryl sulphate broth (LSB) used in the membrane filtration method for the detection of Escherichia coli and other coliform bacteria. Relative to LSB containing the impure dye or its major contaminant, the purified phenol red provided clear visualization of discrete yellow colonies observed against a white background. The colonies remained stable for at least 24 h at 25°C under standard laboratory lighting conditions. This simple procedure will enhance the detection of coliforms in samples. 相似文献