[Hygienic-bacteriologic evaluation of methods for production of dry poultry feces manure]

The application of procedures with dry faeces and the technologies of utilizing faeces for the production of fertilizers on the basis of these procedures are gaining importance, particularly in the confinement of laying hens. However, homogeneous criteria for the assessment of these procedures from a hygienic point of view are not yet available. Since salmonellae are the highest infection risk in layer faeces, freedom from salmonellae is the decisive criterion for epidemic-hygienic harmlessness. The indicators salmonellae and E. coli are recommended for assessing the composting of layer faeces. The product should be free of salmonellae and E. coli. Furthermore, the temperature of the product, the dry substance and the pH value should be registered since these parameters correlated with the potential indicators of hygiene. S. enteritidis had a particularly high tenacity in layer faeces. Fresh and dried faeces and layer faeces from battery management and faeces from intensive floor management were investigated and compared with bacteriological and physicochemical methods. The chemical and bacteriological findings were in good accordance with data from the literature. However, the frequent occurrence of salmonellae in the faeces of clinically healthy flocks is described for the first time. Salmonellae were isolated from 83.9% of the samples from battery management and from 1.9% of the samples from floor management. A total number of 15 salmonellae serovars, most frequently of S. enteritidis, occurred in cage management. The production of dry faeces by means of the aeration of the conveyor belt seems to be less favourable than the production of dry faeces in intensive floor management. Salmonellae and E. coli could not be cultured any more after the clamp composting of layer faeces from the conveyor belt under summer and winter conditions. Minimum conditions which led to the death of native salmonellae were a rise of the pH value of > 9.0 over days, with the temperature of the product in the compost heaps amounting to at least 18.4 degrees C. Test salmonellae could not be cultured from compost heaps of dry layer faeces from the 4th day onwards, native salmonellae from the 7th day onwards (summer) and the 25th day onwards (winter) and E. coli from the 88th day onwards. Layer faeces from conveyor belts must be composted before their utilization as fertilizers since they can contain high concentrations of native salmonellae even in healthy flocks of laying hens. According to the available results, it is sufficient to store the faeces at least 12 weeks outdoors. The resetting of clamps is not necessary. This period might be shorter in summer.