Probiotics - Possibilities and limitations of their application in food, animal feed, and in pharmaceutical preparations for man and animals

Probiotics are cultures of special microorganisms, which have been used as feed additives since the seventies of the past century and already since th e twenties in food specimen and in pharmaceuticals. The definition of "Prob ioticum" was formulated in 1974 simultaneously with the use of living cultu res in feed for various animals in order to substitute the application of n utritive antibiotics or chemotherapeutics. In the meantime probiotics are applied not only as feed supplements or phar maceuticals but increasingly in suitable food specimens such as dairy produ cts, fruit juices, chocolates, and even meat products. Of course, heating o f such products prior to consumption or application must be ruled out. The selection of a suitable strain of a microorganism can be regarded as th e primary requirement for the use as a probiotic. These cultures must be ab le to pass the stomach-duodenum barrier in a viable state and to multiply a t the site of destination in the intestine. Additionally, they must be capa ble of producing antagonistic metabolites against a dominating saprophytic microflora resulting in a competitive growth. These abilities are common am ong lactic acid bacteria, e.g. lactobacilli and bifidobacteria. Yet, intend ed autochthonous species do not possess very good technological features fo r the enrichment in food specimens, because their viability will decrease r apidly under unfavourable conditions as it is the case with mineral supplem ents in feed or with low acidity in fermented dairy products. Therefore, so me other microorganisms like spore-forming species or yeast cultures were i ntroduced as probiotic components. These possess some similar features whic h render them suitable for probiotic use. But their physiological and ecolo gical traits do not qualify them as probiotics of first choice. The special efficacy of probiotics must be strictly verified in animal nutrition due t o restrictive EC-regulations, in pharmacy due to legal restraints, and in f ood applications in accordance with food law regulations. Safety aspects ar e considered very restrictively in feed applications, in the food and pharm aceutical sector they should be in accordance with the intended purpose of "fulfilling health claims". In the presented review the different requirements for the application of p robiotics in animal nutrition, in food, and in pharmaceuticals will be prov ided. The special effect of competitive exclusion of pathogenetic and toxin ogenic microorganisms in fowl performance are mentioned and even the applic ation of probiotics as marine aquacultures of fish and Crustaceae will be i ncluded. Furthermore, the safety aspects resulting from the tremendous amou nt of industrially produced cultures which are distributed into the environ ment will be discussed. In conclusion it may be pointed out that probiotics may serve to partially replace the presently reduced or even prohibited ap plication of nutritive antibiotics or chemotherapeutics in animal nutrition and in fulfilment of health claims in man and animals. Economic and enviro nmental aspects will reduce the overall application of probiotics world-wid e. Restrictions of use and controls of efficacy and safety are essential an d must be implemented periodically.