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Biomedical subjects

D Strauch

Publications and source records attributed to D Strauch.

At least 55 records · Page 3Linked to original sources
PubMed1983

[Communicable disease problems of sewage sludge].

Sewage sludge is a concentrate of pathogenic agents which survived the sewage purification processes. Such hazardous sludges therefore should be disinfected prior to their utilization in agriculture. Necessary technologies for each size of treatment plant are on the market available. The new ordinance for the agricultural utilization of sewage sludge which comes into force the 1 April 1983 meets to a large extent the expectations of hygienists.

Agriculture↗
PubMed1981

[Removal of polio- and parvovirus in sewage-sludge by lime-treatment (author's transl)].

Lime (CaO) applied as conditioner for dewatering municipal sewage sludge in filter-presses is suitable to disinfect sewage sludge with respect to virus. A pH-rise to more than 12 followed by release of ammonia inactivates Polio- and Bovine Parvovirus. Addition of 3 kg CaO and more per m3 of raw sludge inactivates Poliovirus within 30 minutes. 7.5 kg CaO per m3 of anaerobically digested sludge are required to inactivate Polio-virus within 5 days and Bovine Parvovirus within 24 hours. Parvovirus seems to be more sensitive against free ammonia than Poliovirus, but less sensitive against high pH-values.

Calcium↗
PubMed1981

[Survival of salmonellas and ascaris eggs during sludge utilization in forestry (author's transl)].

Salmonella senftenberg survived in sewage sludge after a single application in summer in experimental plots of 11 different forest stands between 424 and 820 days. After application of infected sludge in winter the survival times were between 104 and 350 days. Salmonelles adsorbed to germ carriers located on or below the sludge layers survived for a shorter time than those germs which were suspended into the sludge. Ascaris eggs survived not longer than between 78 and 107 days. It is therefore recommended to prohibit the utilization of infectious sewage sludges in forests and at their edges as it is handled in Switzerland. If this cannot be achieved the permission for utilization of sludge in forests should only be given if the sludge is tilled into the soil.

Agriculture↗
PubMed1980

[Investigations on disinfection and sterilization of surfaces by ultraviolet radiation (author's transl)].

Some model investigations have been made in order to find out if disinfection or sterilization in an ultraviolet radiation cabinet (fig. 1) is effective. The reduction rate of spores of Bacillus anthracis dried to germ carriers of aluminium, ceramics or wood was used for indicating the germicidal effect. It was found, that a 7.5 times higher dose of radiation was necessary to reach a similar reduction rate of spores on germ carriers of ceramics as it was found for the ones of aluminium (tab. 1 and 2). Very high dosage of radiation was necessary to get a safe reduction of spores on each germ carrier (fig. 2 and 3). On wooden germ carriers an average logarithmical reduction (R) of no more than 0.67 was found after 30 h of exposure (tab. 3). Unreliable results have been found in the sterilization experiments with spore bearing germ carriers of aluminium and ceramics. In a few rare cases sterility could be obtained by an ultraviolet radiation dose of 2.000.000 microW s/cm2 (tab. 4). But generally a dosage of even 222.600.000 microW s/cm2 was not sufficient to sterilize the copntaminated germ carriers. The ultraviolet radiation cabinet cannot be recommended for disinfection or sterilization.

Bacillus anthracis↗
PubMed1980

[Survival of anthrax spores on surfaces (author's transl)].

The survival of spores of Bac. anthracis on the surfaces of wood, resopal, aluminum, teflon, PVC, lacquered sheet metal and ceramics was investigated during a period of 987 days. Two figures are showing the logarithmical reduction rates of germ counts on these materials. The lowest reduction rates were found on wood, the highest on ceramics. On dark surfaces the reduction rate was not as high as on light ones. The increase of relative humidity from 35% to 45% seems to enforce th inactivation of the spores of Bac. anthracis.

Aluminum↗
PubMed1980

[Disposal of carcasses and rendering in the waste management program 1975 of the Federal Republic of Germany and hints for the practice of supervision by state veterinarians and operational self-control in rendering plants (author's transl)].

In the Waste Management Program 1975 of the German Federal Government the problems of disposal of animal carcasses and rendering were specially emphasized in the working group "Animal Residues". Besides a description of the entire situation, the reasons and the problems, measures for solving the problems are concurrently listed. For the practical supervision of rendering plants by the state veterinary officer and the operational self-control in such plants a questionnaire was prepared on the basis of the law in force, which can be used as a checklist.

Abattoirs↗
PubMed1978

Some hygienic problems in the production of meat and bone meal from slaughterhouse offal and animal carcasses.

A study of uncut anthrax-infected slaughterhouse waste in the sterilizer of an animal destructor after the prescribed heating at 130 degrees C for 30 min showed that in 17 cases Bacillus anthracis was able to survive. The determination of z-values for B. anthracis and B. stearothermophilus showed that when slaughterhouse waste is cut up into pieces of no more that 50 g weight the temperature at the centre may lie between 120 degrees C for 20 min and 130 degrees C for 10 min for destruction of spore formers. The resulting animal meal is of improved protein quality by this treatment. These results and conclusions cannot be directly transferred to fat bath treatment of meat, because of the significant difference caused by the use of vapour pressure methods.

Abattoirs↗
PubMed1978

[The differentiation of clostridial microcultures on nuclepore-filters by fluorescent antibodies as a rapid screening test for spores. I. Method of producing microcultures (author's transl)].

Spores of 32 strains of 11 different clostridial species (Table 1) were allowed to germinate as microcultures on Nuclepore membrane-filters to ascertain whether they could be differentiated according to their patterns of growth. The questions dealt with in the preliminary studies, investigated which pore-size of filters would be best for this purpose and which time necessary for each species to produce microcolonies of 10 to 20 cells from a single spore. Nuclepore-filters with a pore-diameter of 1 mu gave the best results and the times for producing microcolonies of the desired size ranged from 4 hours with Cl. septicum up to 10 hours with Cl. tetani (Table 3). The final result of the study was, that the differences in the patterns of growth were not great enough to allow identification. Only Cl. perfringens formed specific and distinctive compact colonies (Tables 4 and 5).

Bacteriological Techniques↗
PubMed1978

[The differentiation of clostridial microcultures on nuclepore-filters by fluorescent antibodies as a rapid screening test for spores. II. Application of fluorescent antibodies (author's transl)].

The study deals with the question of whether a combination of microcolony-cultivation on polycarbonate-membrane-filters with the fluorescent-antibody-method will lead to a rapid-diagnosis method for clostridial-spores. Formaldehyd-inactivated vegetative cells of eight different clostridial-strains (Table 1) were used for the immunisation of rabbits according to the method published by Böhm and Strauch (5). The results of the immunisation procedure, developed for aerobic-sporeformers, showed, that satisfactory results could not be obtained in all cases (Table 2). The eight conjugates were tested against microcolonies of 32 strains of different clostridial-species on membrane-filters, produced by the technique described in the first communication. The results showed (Table 4) that differentiation was always possible when homologous antisera were used. In most cases, in order to differentiate between the various species, conjugates of several serotypes had to be employed together. However due to their uniform antigenic nature, Cl. feseri and Cl. tetani could both be identified by using one strain for each to immunize. With clostridial-spores the species could be identified within a period of 6 to 12 hours by using the membrane-filter-fluorescent-antibody technique.

Antibodies, Bacterial↗