Corkstoppers used as closures for wine and champagne are more and more doubted by the wine industry because of their possible flavour damaging microbial and chemical properties. Wine producing and wine trading enterprises demand a radical improved reliability of the product, otherwise its substitution by synthetic closure materials. A displacement of corkstoppers by synthetic substitutes will have an seri-ous socio-economic impact, because it imperils the continuance of a large number of the cork producing and refining enterprises.
The MCI Project (internal title of this project) aimes to conquer this development by a significant improvement of the reliability of the products. This task comprises the reduction but better extinction of the microbial burden and a control of the chemical contamination of corkstoppers in the course of the production processes by:
-. a systematic scrutinization of all current steps of cork processings conducted by the SME-proposers,
- for their influence on the naturally occuring contamination of the cork by microor-ganisms (bioburden),
- for events of an introduction or production of chemical contaminants,
. by a screening for new techniques of processing, helping to avoid the rise but better cut off the number of microorganisms in corkstoppers and without ecologi-cal, toxicological and sensorical side-effects,
-. by a first scaling up of the laboratory methods for a small scale production in the plants environs.
The most important tools applied in the course of the project were: the quantitative assay for the microbial activity in cork CORA (Cork Activity Assay), a gas-chromatographical method for the determination of the microbial activity in cork materials, that was developed by the RTD-performer(1) and an extensive chemical analysis of corkmaterials, water, glues, chemicals and other materials used in the course of the corkstopper production.
The project ended with the termination of its third phase on December 31th 1998 in which the prototype of an innovative treatment technology, that was designed and constructed following the specification of the RTD-performer, was tested under laboratory and plant environs conditions.
The innovative technique developed in the course of the project CR-5144 enables cork producing enterprises to solve the major problems related to the tradional way of corkstopper production:
- the uncontrolled development of microorganisms with the risk of an off-flavour formation,
- the introduction of chemical contaminants which may alter the aroma and flavour of wine and other corkstopper closed beverages directly or subsequent a micro-bial transformation,
- the rapid and controlled drying of corkmaterials independent their outstanding thermal insulation properties.