An Ecological Study of the Psychrotrophic Bacteria of Soil, Water, Grass and Hay

Druce, R. G.; Thomas, S. B.

doi:10.1111/j.1365-2672.1970.tb02215.x

Cited by 25 publications

(11 citation statements)

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“…They were also apparently the most successful colonizers of the sites sampled within the abattoir. The latter environments are predominantly wet and may differentially favour their development (Druce & Thomas 1970;Blaise & Armstrong 1973; Jones 1973). The elimination of these bacteria from all sites in the abattoir would be extremely difficult, and in most areas would appear to serve little practical purpose.…”

Section: Discussionmentioning

confidence: 99%

“…The microflora on the hide or fleece will be derived mainly from soil, water and vegetation, as well as faecal material. Psychrotrophic bacteria, the group which includes potential spoilage bacteria for chilled meat, are common in soil, water and vegetation (Stokes & Redmond 1966;Druce & Thomas 1970;Warskow & Juni 1972;Jones 1973). Pseudomonas, Moraxella and Acinetobacter appear to be found more commonly than Gram positive bacteria in water and on vegetation.…”

mentioning

confidence: 99%

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Sources of Psychrotrophic Bacteria on Meat at the Abattoir

Newton¹,

Harrison²,

Wauters³

1978

Journal of Applied Bacteriology

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An export abattoir was examined to determine the sources and types of psychrotrophic bacteria which gain access to meat. Gram negative psychrotrophs were recovered from the hides, from structural and work surfaces within the abattoir, and from carcasses and meat at all stages of processing. Microbacterium thermosphactum was recovered intermittently at all sampling sites. Psychrotrophic and total counts and the incidence of M. thermosphactum on carcasses and meat increased during processing through the abattoir. Structural and work surfaces may be as important as the hide as sources of bacterial contaminants on meat. Seasonal variation was observed in psychrotrophic counts which correlated positively with rainfall and negatively with temperature.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Sources of Psychrotrophic Bacteria on Meat at the Abattoir

Newton¹,

Harrison²,

Wauters³

1978

Journal of Applied Bacteriology

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“…Facultatively psychrophilic bacteria are widespread in terrestrial and freshwater habitats (Stokes and Redmond 1966;Druce and Thomas 1970). Since obligate psychrophilcs are metabolically more active at lower temperatures than facultative psychrophiles (Ingraham and Stokes 1959), adaptation to these lower temperatures would imply greater metabolic activity, and the cycling of lake nutrients would continue at a high rate during winter.…”

Section: Discussionmentioning

confidence: 99%

Bacterial Decomposition Processes in Lake Wingra Sediments During Winter1

Boylen

Brock

1973

Limnology & Oceanography

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Throughout winter, viable counts of bacteria from sediments of Lake Wingra (Madison, Wisconsin) at several different incubation temperatures were always higher at 25°C than 4"C, although the temperature of the sediments remained below 4°C for over 3 months. All of the organisms isolated and initially cultivated at 4°C grew better at 25°C; no obligately psychrophilic bacteria were found. Isotope studies to measure the temperature optima of the resident bacterial flora showed that the optimunl tcmpcraturc for incorporation of 14C-glucosc into cell material and conversion of l"C-glucose into l*C-COT remained at 25°C or greater all winter. A true psychrophilic flora does not develop in these sediments in winter, and bacterial decomposition processes occur at a much slower rate in winter than in summer.Lakes in temperate climates show marked variations in temperature through the year. In Wisconsin, inland lakes are covered with ice for 3 or 4 months, and during this period temperatures of the water and sediments remain below 4°C. It was of interest to see whether bacteria in sediments became adapted to these low temperatures, since if they did, rates of bacterial metabolism might be expected to be higher than if adaptation did not occur.The fact that microorganisms are capable of adapting to low temperatures has been well documented. Obligately psychrophilic bacteria (with temperature optima below 2O'C) have been isolated from constantly cold marine environments ( Morita 1966 wide seasonal temperature variation. Temperate lake sediments constitute natural habitats where temperatures vary by the season but where the winter low of about 1°C and the summer high of 30°C remain relatively constant for several months each year. Does the microbial flora show a single optimum temperature toward either end of this temperature range or is it in a continual state of adaptation to the seasonal temperature changes in the environment? Possible answers to these questions were sought by determining temperature optima directly on the resident bacterial populations using radioisotope techniques and indirectly by culture techniques. MATERIALS AND METHODSLake Wingra is a small calcareous lake in the city of Madison, Wisconsin, at an elevation of 254 m. It is shallow, with a maximum depth of about 5 m; much of the lake was created by dredging from a marsh to provide fill for the construction of Vilas Park. We chose a single station at the southwest corner of the lake, in about 1 m of water, because it was amidst beds of water weeds which had contributed heavy organic matter to the sediments. Most of these weeds had become fragmented or decomposed before our study was made, although occasionally a fragment of plant material was present in the sample. Ice-

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“…Since the surface water areas in southern Indiana become warmed to temperatures above 20 C in summer, it seems unlikely that obligate psychrophiles inoculated into them could survive; hence, they could not become inoculated into the spring systems. Facultatively psychrophilic bacteria are widespread in terrestrial and fresh-water habitats (Stokes and Redmond, 1966; Larkin and Stokes, 1966;Druce and Thomas, 1970;Sinclair and Stokes, 1964) and are probably the source of the bacteria present in the springs. …”

Section: Temperature Variation Of the Habitat-temperatures Of The Vamentioning

confidence: 98%