[Facts and speculations on viruses in food (author's transl)].

Abstract

The danger to which man is exposed as a result of viruses contained in food differs basically from the risk to man caused by bacteria, fungi or their toxins. With respect to viral injuries it is not the specific diseases (e.g. hepatitis and polio) that are in the foreground but the much more dangerous noxious groups whose cause/effect relationships are rather complex. 1. the oncogenic risk, 2. synergistic interactions with opportunistic problem viruses, 3. slowly developing chronic diseases and persistent infections with their indirect injuries, 4. new infectious pathogens (viroids). Viral contamination of food can be exogenous or endogenous. Exogenous contamination is possible by: 1. specific human-pathogenic viruses, 2. polyphagous, human-pathogenic and animal-pathogenic viruses (zoonosis), 3. animal-pathogenic viruses only, 4. fish viruses, 6. bacteriophages, 7. fungal viruses. The viruses of group 1 and 2 are of practical importance, those of group 6 and 7 are it occasionally. Endogenous contamination is caused when an animal suffered from a viral infection at the time of slaughter or product extraction (e.g. milk, egg, fish) or when the animal has picked up a virus shortly beforhand. As far as endogenous contamination is concerned, a distinction must be made between 1. primarily biological and 2. primarily mechanical contamination. For the first, mainly the clinically inapparent especially persistent infections and viraemic stages at the end of incubation are dangerous. In both cases the animal is clinically healthy. In primarily biological contamination the zoonosis viruses predominate. In addition the bacteriophages must be taken into account. Primarily mechanical contamination is restricted to fish, molluscs, milk and eggs. The possibilities and consequences of exogenous and endogenous contamination are discussed. The risk of viral transmission by foodstuffs depends chiefly on the tenacity of the virus in the affected food, but also on its virulence and concentration. Basic considerations are discussed. Practically from any useful, healthy animal the most varied viruses can be isolated. In order to avoid destroying the confidence of the consumer, it is necessary to take stock of the following: 1. viral contamination in foodstuffs demonstrated so far 2. verified human diseases caused by the intake of virus-contaminated foodstuff and 3. speculations on imaginable consequential damage caused by the consumption of food containing virus. This is also dealt with in the paper. In a final, critical review the importance of virus contained in food is discussed comprehensively from a scientific, legal and practical point of view.