2005 GENERAL ASSEMBLY March 11, 2005, Paris AWine making practices adapted to the sanitary risks PHILIPPE COTTEREAU (ITV, Nîmes) France

Since the EEC directive N°93-43, of 06/14/1993 and transposed into French law by the decree from 05/28/1997, the control of the food healthiness must be managed by firms. The risks analysis to each stage of the development has to be realised by each company. In order to help the firms, “hygiene good practices guidelines” (wine network, publication: edition of July 1999, “Imprimerie des Journaux Officiels”) are being worked out and take into account the method "Hazard Analysis of Critical Control Point" (HACCP). Relatively few risks, compared to other food sectors, were identified. The present intervention will examine, for example of possible adaptations of the enological processes to control the risk that have been identified : SO2, foreign molecules resulting from micro-organisms activity (like Ochratoxine A), pesticide residues in wines. SO2: SO2 is the main tool of oenologist to guarantee the quality of wine delivered to the consumer. This tool however, presents a proven toxicity which lead to regulate its final concentration in wines. SO2 has multiple properties: bactericide, fungicide, antioxydant... Today, there is no product of replacement having the whole properties of SO2. Ascorbic acid, used with SO2 can reduced SO2 amounts, and increase protection against oxidations, but only during setting out in bottle. Even if its use is not yet authorized in Europe, ascorbic acid could be used on musts but would not reduce the final level of SO2. In this case the role of ascorbic acid is to increase protection against oxygen in the pre-fermentary phases of white or pink wine makings, in particular by protecting flavours or the sulphur flavours precursors. Dimethyl dicarbonate (DMDC) is a fungicide, but its efficacy is not strong enough to be used alone. In case of wine with residual sugar, DMDC can be used in association with SO2 to decrease total amounts of SO2. This association is necessary because DMDC does have any antioxydant property. This molecule breaks up into CO2 and methanol. Lysozyme is an enzyme wich can destroy the walls of Gram+ bacteria, and so control the lactic bacteria population. This enzyme have no antioxydant and fungicide activity and is inactive against acetic bacteria. It is necessary to use it in association with SO2. Using lysozyme in case of lactic bacteria diseases is very interesting, when only bactericide activity is required. Lysozyme presents an allergic risk for the consumer. Studies are carried out to evaluate this risk. Decreasing a few tens of mg/L SO2, lead to add several hundreds of mg/L of these alternate products!... Using physical stabilizing treatments like Cross-Flow microfiltration or the Flash-pasteurization can eliminate the micro-organisms population and reduce SO2 needs, always necessary for two reasons : (i) its antioxydant activity and (ii) its ability to avoid a recontamination by undesirable micro-organims. Labelling SO2 on bottles of wine will be required after 11/25/2005. Ochratoxine A (OTA) : Ochratoxine A is mainly produced on the grapes by Aspergillus carbonarius. Careful vine practices in order to get a good sanitary level of the harvest, can strongly reduce the risks of contamination by this Aspergillus (in particular control of grape berry moth – Eudemis). The enological routes may then reduce final OTA level. The use of active carbon is very effective but remains not adapted for red and pink wines. Fining of wines may allow a light reduction of concentration. The walls of yeasts may adsorb OTA, and ageing on lees or yeast / yeast walls addition may decrease, almost weakly, the final concentrations. Due to its solubility, OTA is more solubilized by alcohol than by water. Pressing before alcoholic fermentation will reduce OTA extraction in comparaison with traditional red wine making with marc maceration. For an hazardous vintage, it should be interesting to carry out pink wine making type or heat extraction to have red wine (heating the grapes followed by pressing and wine making in liquid phase). A maximum limit is now fixed in the wines at 2µg/L by the 123/2005CE decree and this decree will concern all products of the 2005 vintage. Pesticide Residues: In Europe, the regulation defines Maximum Residue Level (MRL), which concern grapes but not wines. Reflexions are led to determine MRL on wines. However, during transformation of wine grapes, pesticides can be metabolised into new potentially more toxic molecules than the previous. The various enological routes can lead to significant differences. For example, dithiocarbamates present on grapes can be transformed during wine making by heat extraction, in ethylene thio-urea (more toxic product than the dithiocarbamates). So the choice of enological route is significant for grape harvest which has been treated by the dithiocarbamates. In future, it will be necessary not onely to define MRL on wines but also to consider the incidence of the wine making techniques on the formation of possible metabolites. Ochratoxine A (OTA) ochratoxine A is produced on the grapes in majority by a aspergillus carbonarius