[Problems of food hygiene with carriers of microorganisms and permanent excretors]

To appraise the significance of chronic excretors and carriers for the development of "food poisoning", the analysis must also include the food. First of all, the question arises as to whether foods only have a vector function or whether an increase in the bacterial count is an important prerequisite for the elicitation of human disease. When pure intoxication pathogens are not involved, this question arises in connection with the minimum infectious dose. A classification of the most important causative organisms of bacterial foodborne infections and intoxications is presented in the light of these considerations. If foods only have a vector function, hygiene measures are automatically concentrated on excretors in order to prevent the bacteria from passing into foods. When this is not the case (as in the vast majority of human foodborne infections and intoxications of bacterial origin), two strategies can be successfully applied. First of all, precautions must be taken to rule out bacterial contamination. On the other hand, an increase in the bacterial count, i.e. proliferation of the pathogens in the food must be prevented by appropriate measures. The interacting factors are described. The example of salmonellae is cited to illustrate the routes of contamination from excretors (humans and animals) to foods ready for consumption and possible hygiene measures.