Zentralblatt fur Bakteriologie, Mikrobiologie und Hygiene. 1. Abt. Originale B, Hygiene最新文献

Reliable hygienic conditions in food processing are necessary to exclude any risk for human health and to secure the supply with high quality products. In the processing plant are cleaning and disinfection of high importance. For comparative evaluation of these processes three characteristic values are introduced: The volume/surface ratio indicating the total available solution, the active substance/soil ratio indicating the chemical capacity, and the flow/reacting film ratio indicating the mechanical exchange frequency during the treatment. Some examples elucidate the correlations between plant and test conditions respectively. Means of improving plant hygiene and the possibilities of supervision and legislation to that purpose are discussed.

The increasing occurrence of infectious enteritis caused us to perform a prospective, epidemiological pilotstudy in households, in order to receive informations about the practicability of such a project and the bacteriology of food prepared at home as well. 10 families were asked to gather samples of all foodstuffs consumed during the day in separate containers and to keep them frozen at - 20 degrees C until collected by us once a week. Thus we received 4.683 samples within a 6-months-period. In the laboratory those samples were mixed following Table 2 and examined concerning the occurrence of enteropathogenic bacteria. Additionally we carried out an investigation of kitchensurfaces and -utensils by means of "Rodac"-plates. The evaluation of the food-samples showed no growth of salmonella, shigella, yersinia or campylobacter; however, in 267 samples were found staphylococci, in 191 enterococci, in 388 enterobacteria, in 28 aerobic sporeformers and in 144 fungi. Mainly sausage- and meatproducts appeared to be contaminated by staphylococci, also enterococci and enterobacteria (Fig. 1); other groceries were colonized by these microorganisms only to a minor degree. Fungi and aerobic sporeformers were isolated primarily in salads, bakery- and milkproducts (Fig. 2). Though some of the foodstuffs contained up to 10(5) pathogenes/g (Fig. 5), no cases of gastroenteritis were observed within our families. In case of mishandling (e.g. storage of food in refrigerators with temperatures above 4 degrees C) the development of foodborne enteritis has to be taken into account. The kitchens' examination showed a relatively high degree of contamination with pathogenic resp. potentially pathogenic organisms, represented in Fig. 7 by data obtained from different objects of investigation (surfaces, sinks and cloths).

Various aspects of the bacteriology of inedible rendering have been investigated in order to establish a solid basis for future decisions concerning an up-to-date and flexible legislation on rendering. Thermal death (TD)-graphs for spores of B. cereus and Cl. perfrigens, PA 3679 (Fig. 3), and heat transmission equations for animal tissues have been determined. By using the heat transmission data for bones and the TD graphs for the spores it is possible to predict the decimal reductions of spores in the centre of the largest pieces present during a given rendering process, thus establishing conditions for bacteriological safe processes. The calculations show that predrying for 45 min followed by cooking at 125 degrees C for 15 min and final drying ensures destruction of non-sporeforming bacteria and Bacillus anthracis spores even in the centre of 70 mm bone particles while heat resistant spores of clostridia are virtually unaffected. By reducing the particle size to less than 40 mm, the same process will result in a reasonable reduction of heat resistant clostridia spores, too (Table 4). In order to verify such theoretically calculated effects a new technique has been developed in which steel tubes containing a paste inoculated with spores were inserted in bones. These were treated in a cooker, were caught during discharge and examined. The results confirmed the calculations (Table 5). Most modern rendering systems (Carver-Greenfield, Stork-Duke, Wet Pressing) are continuous without pressure cooking and a common feature is a fine mincing minimizing the problem of heat penetration. In order to obtain information regarding the thermal sterilizing effect in such systems investigations were made in a pilot cooker using inoculated meat-and-bone meal mixed with water and/or fat. Regardless of whether fat was added or not sterility was found for samples containing water when the temperature during drying reached 110-120 degrees C, whereas cooking in fat only drastically increased the heat resistance of spores of both strains. Sterility was only obtained at temperatures of the order of 140 degrees C, a fact of minor importance for rendering, where thermal treatment usually takes place with moisture present. The decimal reductions actually found were compared to calculated ones and the former were all substantially higher than the latter (Table 6). Thorough investigation of sterilization in the wet pressing system has confirmed the conclusion that inactivation of pathogenic microorganisms during drying is obtained when temperatures reach 110 degrees C (Table 7 and 8).(ABSTRACT TRUNCATED AT 400 WORDS)

Materials used in drinking water may lead to an increase of microorganisms. Microbiological examinations of material in jar tests have been repeatedly dealt with in literature. However they yielded contradictory results. Within the scope of these examinations it was to be found out if and under which conditions an experimental examination of materials, the criterion of test being microbial growth in water, is possible. For the examinations in jar tests it is necessary to have a minimal concentration of mineral salt in the water and to use germs which can degrade the components issued by the materials.

2429 samples of drinking water supplies in South Bavaria were examined for Yersinia between October 1982 and March 1983. Yersinia enterocolitica was isolated from 82 of 1650 samples of central water supplies and from 42 of 779 samples of decentralized water supplies. Only three of these strains were serotype O3 but indole-positive and different by that from the indole-negative human pathogenic serotype O3 which is most frequent in Western Europe. No strain was serotype O9. Y.e. was more often isolated from water samples which were objected according to the German drinking water decree to contain Escherichia coli, coliforms or increased colony counts. This points thereupon that Y.e. do not originally belong to the saprophytic soil bacteria but reaches the drinking water subsequently by fecal pollution. As compared with ENDO-Agar, CIN-Agar was found the preferable medium with a three times higher isolation rate. In addition, Y. intermedia and Y. frederiksenii were isolated from 20 and 23 samples respectively.

According to age-standardized mortality rates (European standard population, Fig. 1) and mortality rates by birth cohort and age at death (Fig. 2-7) the trends of mortality of stomach and colorectal cancer (1966-1981/82) were analysed for men and women. In a further step it was examined how far these trends could be explained by the hypothesis "diet and cancer" (western diet). Under the postulation that the manifestation of western diet has reduced the risk of stomach cancer drastically, the risk of colorectal cancer has not increased to the same extent. Moreover, rectal cancer has shown only a slight increase and might even decrease in years to come. Having in mind the increasing risk, diet has no major impact so far. The differences in trends according to age groups and birth cohorts indicate the influence of other factors than diet. Furthermore, it is necessary to deal with colon and rectal cancer separately because of the differences in their trends.

A method for the determination of the bacterial growth rate as parameter for the biodegradability of organics in water is described. The increase of the number of bacteria during incubation is measured by turbidity (12 degrees forward scattering) and total cell number counted in the microscope. The method allows to define the influence of water treatment steps (ozone, activated carbon filtration) on the growth rate being a decisive criterion on regrowth problems in distribution systems.

Four different dental units (Sirona 2000, Sirodont S, Sirona 2000 and Siro I) used in conservative dentistry were investigated bacteriologically by analysing water samples from the tumblers, the assistant's spray, micromotors, hand sprays at the units and from the scalers. The results of the analysis (shown in Table 2-5) reveal that micro-organisms of the Pseudomonas group were mainly found in the turbines and also in the micromotors. In other areas of the equipment micro-organisms of the acinetobacter species were frequently identified. The germ counts were very high, especially in the morning, and not infrequently reach levels as high as 50,000 germs/ml. For disinfection isopropyl alcohol and Tego 103 S were used; the latter was found to produce a good disinfecting action following prolonged exposure. Further requirements and recommendations for hygiene in the dental practice are briefly discussed.

Among the three measures, which are capable of producing a preventive effect against caries only when applied combined, i.e. adequate fluoride supply, proper mouth hygiene and healthy nutrition, the latter is dealt with in greater detail. The use of sugar substitutes is discussed under the aspects of caries prevention, substitute composition and production technology as well as from a medical point of view. Among the presently available sugar substitutes with nutritive value are mentioned Xylite, Lycasine, Mannite, Sorbite, Palatinite, the non-calorific substitutes such as the natural Aspartame as well as the synthetic sweetening agents Saccharine and Cyclamate. The possibilities and limitations of using these sugar substitutes in the prevention of caries in adults and children are presented.

The groundwater, polluted with hydrocarbons, showed large cell numbers during one year of examination: 10(3)-10(4) CFU/ml grown on N-agar after 5 days at 20 degrees C, 10(4)-10(5) CFU/ml grown on water-agar after 8 weeks at 20 degrees C and total cell numbers of 10(5)-10(7)/ml. The bacteria, which were isolated from N-agar, were chiefly Pseudomonas, Flavobacterium, Acinetobacter, and other gramnegative species, Arthrobacter and Bacillus as members of grampositive bacteria. Furthermore the following "physiological' groups were found in the groundwater: ammonium-oxidizing bacteria (MPN 10(1)-10(2)/ml), sulfur-oxidizing bacteria (MPN 10(1)-10(4)/ml), nitrate-reducing bacteria (MPN 10(3)-10(6)/ml), denitrifying bacteria (MPN 10(1)-10(4)/ml), spores of aerobe spore-forming bacteria (2-30/ml), spores of anaerobe spore-forming bacteria (0.2-0.4/ml), manganese-oxidizing bacteria (10(3)-10(4) CFU/ml) and Actinomycetes (0.1-1.0 CFU/ml).