Physical Methods of Sterilization of Microörganisms

Rahn, Otto

doi:10.1128/mmbr.9.1.1-47.1945

Cited by 60 publications

(24 citation statements)

References 38 publications

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“…More reliable estimates of detergent toxicity (Table I) indicate that a simple relationship between surface tension and toxicity is not likely, since many detergents are acutely toxic at concentrations which affect surface tension to a negligible extent. The toxicity of detergents to bacteria has been investigated more fully in this respect, and it is clear that surface tension is not related causally to toxic effect (Rahn, 1945;Glassman, 1948). That surface activity is nonetheless important may be inferred from the fact that detergents in homologous series differ in toxicity, frequently showing a clear relationship between structure and activity.…”

Section: Mode Of Action Of Detergents On Fishmentioning

confidence: 99%

Toxicity of synthetic detergents to fish and aquatic invertebrates

Abel

1974

Journal of Fish Biology

212

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Synthetic detergents are reported to be acutely toxic to fish in concentrations between 0.4 and 40 mg/l. Factors affecting toxicity include the molecular structure of the detergent, water hardness, temperature and dissolved oxygen concentration; the age and species of the test fish, and acclimation to low concentrations of detergent. Some of these factors appear to be of only limited importance. Gill damage is the most obvious acute toxic effect; the immediate cause of death may be asphyxiation, but detergents may also be toxic internally. Lethal effects not related to gill damage have not been investigated. Sublethal effects include retardation of growth, alteration of feeding behaviour and inhibition of chemoreceptor organs. Low levels of detergents may also increase the uptake of other pollutants. Invertebrates, especially in their juvenile stages, are extremely sensitive to detergents: concentrations below 0.1 mg/l interfere with growth and development in some species. The interactions between detergents and proteins, and their influence on membrane permeability may be the basis of the biological action of detergents. Detergents in natural waters are usually partially degraded, and a maximum permissible conccntration of 0.5 mg/l would probably be harmless under most conditions.

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Section: Mode Of Action Of Detergents On Fishmentioning

confidence: 99%

Toxicity of synthetic detergents to fish and aquatic invertebrates

Abel

1974

Journal of Fish Biology

212

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“…Bacteriostatic effects of oxygen at tensions less than 10 atm have been reported for other bacteria. (See Rahn, 1945, for a brief review of earlier work on the subject.) S. faecalis did use small amounts of oxygen when it was available.…”

Section: Xygenmentioning

confidence: 99%

Growth of Streptococcus faecalis under High Hydrostatic Pressure and High Partial Pressures of Inert Gases

Fenn

Marquis

1968

The Journal of General Physiology

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Growth of Streptococcusfaecalis in a complex medium was inhibited by xenon, nitrous oxide, argon, and nitrogen at gas pressures of 41 atm or less. The order of inhibitory potency was: xenon and nitrous oxide > argon > nitrogen. Helium appeared to be impotent. Oxygen also inhibited streptococcal growth and it acted synergistically with narcotic gases. Growth was slowed somewhat by 41 atm hydrostatic pressure in the absence of narcotic gases, but the gas effects were greater than those due to pressure. In relation to the sensitivity of this bacterium to pressure, we found that the volume of cultures increased during growth in a volumeter or dilatometer, and that this dilatation was due mainly to glycolysis. A volume increase of 20.3 -4-3.6 ml/mole of lactic acid produced was measured, and this value was close to one of 24 ml/mole lactic acid given for muscle glycolysis, and interestingly, close to the theoretic volume increase of activation calculated from the depression of growth rate by pressure.T h e experiments described in this r e p o r t were u n d e r t a k e n to show t h a t inert gas narcosis c a n occur in the c o m p l e t e absence of oxygen. Previously the narcotic effect of inert gases u n d e r high pressures on Drosophila was found (Fenn, 1965) to diminish with decreased oxygen tension, b u t it was impossible to continue to zero oxygen tension w i t h o u t e n c o u n t e r i n g anoxic effects. H o wever, with a n o r g a n i s m c a p a b l e of growing anaerobically, it should be possible to avoid this complication, a n d so we e x a m i n e d the effects of inert gases on the g r o w t h of a facultative a n a e r o b i c b a c t e r i u m , Streptococcus faecalis.

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“…The two terms z and F define the thermal-death-time curve. The meaning of these factors, particularly z, is discussed by Rahn (22) in terms of QI O and the thermodynamic temperature coefficient.…”

mentioning

confidence: 99%

HEAT RESISTANCE OP STRAINS OP SALMONELLA IN LIQUID WHOLE EGG, EGG YOLK, AND EGG WHITE^a

Osborne

Straka

Lineweaver

1954

Journal of Food Science

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Human and animal pathogens of the genus SaJmrtnelEa, which occur frequently in foods, have been causes of concern to varying degrees for many years, as ably pointed out in the review article by Hinshaw and McNeil (14). The potential health hazard has led naturally to studies of means for eliminating Sdmonella from foods, including studies of heatresistance (4, 5, 9, 10, 11, 25, 27, 30, 31). The references cited concern liquid egg principally, since that is the subject of special interest in this report. These studies show that Xalmonella organisms generally are killed at temperatures above 135°F. Several studies indicate that 1 to 4 minutes a t 142°F. are required to "destroy" Salmonella in liquid whole egg (11, 31) when large numbers are present initially. However, Winter et d.(31) and Solowey (25) both noted the occurrence of heat-resistant strains. At 142'F.(6l.loC.) liquid egg begins to thicken and egg white coagulates in a short time. It is therefore important to determine and to use the minimum heat treatment that will provide adequate safety in the final product. Because of excessive coagulation on heating surfaces it is not practical ordinarily to use higher pasteurization temperatures [ e. g. 160' to 180"F.(71.1 to 82.2OC.)] such as those used for dairy products (7). Egg pasteurization is a borderline operation.The purpose of this report is to extend our knowledge of the heat sensitivity of Sdmonella as a basis for heat treatments or other steps that might be required to provide a satisfactory margin of safety for egg products of various types. Thermal death times and decimal reduction times are reported for a number of strains of Sdmomella suspended in phosphate buffer and in whole egg, egg yolk, and egg white. Six of these strains were used by McCullough and Eisele (18,19,20,21) in their studies of experimental salmonellosis. The effects of p H of suspending medium, numbers, and recovery method on the observed heat resistance will be described. It has not been possible in this study to evaluate certain other pertinent factors such as difference in heat resistance of young and old cells. Available information is discussed with respect to the limitations that exist for the pasteurization of egg products. EXPERIMENTAL Salmonella strains studied. The following strains, representing six types, were used: S. derby 5420 (type B ) , S. barielly CM 688 (type CI), S. newport 5761 (type a), S. pullorum 3083 (type D), S. anatis 5343 and S. meleagridia 5485 (type El), and 8. mftenberg 3252 and 8. senftenberg 775W (type EB). The numbers following 'Presented in part at the 1952 meeting of Institute of Food Technologists, Grand Rapids, Mieh. 451 452 W. W. OSBORNE, R. P. STRAKA, A N D H A N S LINEWEAVER the species refer to strain numbers used at the Western Utilization Research Branch. Ten other strains or isolates were tested in a limited way.Culture and test media. Trypticase soy agar and trypticase soy broth (BBL) were used as cultural media. Brilliant green agar (Difco) was used as the confirmatory medium.The tes...

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Physical Methods of Sterilization of Microörganisms

Cited by 60 publications

References 38 publications

Toxicity of synthetic detergents to fish and aquatic invertebrates

Toxicity of synthetic detergents to fish and aquatic invertebrates

Growth of Streptococcus faecalis under High Hydrostatic Pressure and High Partial Pressures of Inert Gases

HEAT RESISTANCE OP STRAINS OP SALMONELLA IN LIQUID WHOLE EGG, EGG YOLK, AND EGG WHITE^a

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Physical Methods of Sterilization of Microörganisms

Cited by 60 publications

References 38 publications

Toxicity of synthetic detergents to fish and aquatic invertebrates

Toxicity of synthetic detergents to fish and aquatic invertebrates

Growth of Streptococcus faecalis under High Hydrostatic Pressure and High Partial Pressures of Inert Gases

HEAT RESISTANCE OP STRAINS OP SALMONELLA IN LIQUID WHOLE EGG, EGG YOLK, AND EGG WHITEa

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HEAT RESISTANCE OP STRAINS OP SALMONELLA IN LIQUID WHOLE EGG, EGG YOLK, AND EGG WHITE^a