TECHNICAL PROBLEMS RELATED TO IN-VITRO STUDY OF COLON FLORA

The complexity of colon flora and the technical problems encountered i n the sampling techniques and their processing limit the study of its composition and activities. First, we list the main limitations relate d to the sampling procedure-transport and storage. We show that (i) us e of a cryoprotective medium is necessary for sample storage and (ii) that storage has to be at -40 degrees C. Second, bacterial analysis an d enzymatic activities are examined. The lack of specificity of the cu lture media generally used means that systematic studies are difficult to carry out and that bacterial identification at species level requi res genetic techniques. Third, we show that activities of procarcinoge nic enzymes are significantly affected by any kind of storage. Finally , for statistics, the problem of the size and the nutritional habits o f the studied population is examined.