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Dtsch Tierarztl Wochenschr. 1996 Oct;103(10):438-43.

[The epidemiology of helicobacteriosis in humans; studies of the survival capacity of the microbe in food].

[Article in German]

Author information

1
Tierärztlichen Institut, Georg-August-Universität Göttingen.

Abstract

In man suffering from diseases of the stomach and the duodenum (gastritis, ulcus, enteritis, neoplasms), Helicobacter pylori (H..pylori) is frequently detected in the mucous membrane of the stomach. Up to now the spread of this agent is not quite clear. Since the direct transmission in humans can be taken for granted, the following study was to find out whether and for how long the agent mentioned above is able to survive in selected food and whether an infection of the consumer by these contaminated food is possible. 376 samples of secretions from the udder of healthy cows and those with mastitis where tested for the presence of H. pylori along with 100 stomachs of chicken from different flocks. In no case H. pylori could be detected. H. pylori was inoculated in high concentrations into milk and some milk-products. From cooled milk samples the agent could still be reisolated after six days in a density up to 10(3) CFU/ml of milk. At room-temperature or 37 degrees C resp. the pathogen could be detected in milk for three to four days only. In yoghurt the agent kept viable for three hours only, whereas in kefir for 24 hours. Mean survival time of then hours was found in pH-neutral curd cheese. The incubation of H.pylori in sterile drip from chicken and in physiologic saline resulted in maximal survival time of at least 48 hours at room temperature. But in H.pylori-broth the number of microorganisms had dropped below the limit of detectability only after 72 hours. At refrigerator-temperature (7 degrees C) H. pylori could still be detected within these three media after 72 hours in high concentrations. In drip from chicken kept at-20 degrees C before thawing H. pylori showed a considerable survival time. After four weeks its number had only dropped by one to two log cycles, whereas in saline and in broth the agent could not be detected anymore after one week at the most. Experiments concerning tenacity showed: On culture-media with different pH-values the growth-optimum of H. pylori was between pH 6.1 and 7.3 H. pylori was suspended in melting water from chicken and brought in thin layers onto wooden board, plastic and ceramic tiles. The bacterium could be recultured from these surfaces only as long as these were moist. At room-temperature the bacterium could not be detected anymore on wood after 30 minutes, on plastic or ceramic tiles after 90 minutes. At refrigerator-temperature the administered suspensions dried more slowly, so that H. pylori survived longer, but it still could not be isolated anymore on wood after 240 minutes, on plastic or ceramic tiles after 300 minutes. The decimal reduction-time for H. pylori suspensions in broth were. 72 sec. at +50 degrees C 43 sec. at +52 degrees C 20 sec. at +55 degrees C 10 sec. at +57 degrees C 4 sec. at +60 degrees C from which data z = 7.9 +/- 0.01 degrees C can be calculated. From these experiments on can conclude, that in all probability fresh milk and chicken do not contain H. pylori and thus do not represent a source of infection for man. After contamination of slaughtered chicken within the abattoir or from milk and milk-products within dairy industry by insufficient hygiene-management of infected personnel it can not be excluded, that H. pylori gets into households by these foods. An infection of the consumer by this route is not very likely, but can not be excluded with complete certainly.

PMID:
9035978
[Indexed for MEDLINE]
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