Wines withdrawn after chemical tampering claim

Two British supermarkets were clearing their shelves of wines from an Australian wine producer last night after allegations that it had tampered with its own products.

Both Tesco and Waitrose said they had decided to suspend sales of wines produced by Kingston Estate until an investigation by the Australian Wine and Brandy Corporation (AWBC) was completed.

The investigation follows allegations made by two American students who recently completed a period of work experience with Kingston Estate. The students said the estate had added tannins to its wines, blended red wines with unfermented grape juice and used silver nitrate to eliminate the smell of hydrogen sulphide.

Sam Tolley, the general manager of the AWBC, said his inspectors were satisfied that the incidents were of a "technical nature" and that none of the practices presented any risk to public health.

"Nevertheless, we take any allegations very seriously. We need to act quickly in circumstances such as this to ensure that any products which are exported are of the highest quality," he said.

Although it is appears that no health and safety implications are involved, the practice of adding tannins to colour wine is illegal. Kingston Estate faces a hefty fine if prosecuted.

Bill Moularadellis, the chief executive of Kingston Estate, was apparently taken by surprise by the allegations made by the two students, Haydn Wildon and Nicole Haller. He said the winery was fully co-operating with the authorities, especially since the winery was keen to protect its international reputation and that of the Australian wine industry.

Based in the heart of South Australia's Riverland region, Kingston Estate, which is owned by the Moularadellis family, is a large, state-of-the-art winery, producing 24 million litres per year, of which roughly an eighth is bottled, and exporting wine worth about A$12m (£5m) annually. With a reputation for value-for-money wines, production is geared largely to the export market, including the UK to which it ships much of its wine in bulk.

Tesco stocks two of its wines - a shiraz and a mouvedre, which sell at £6.99 and £5.99 respectively. A spokeswoman said yesterday: "We were aware of this very quickly and obviously we had a responsibility to our customers. The wines were removed as a precautionary measure. They are not sold in all of our stores - probably about 450 outlets."

Waitrose sells just one of the estate's products - a wine made from the less usual Petit Verdot grape. It has just 60 cases in stock and sells the wine at £13.99 a bottle. "As a result of the information we have received we have ordered sales of the wine to be suspended until we have further information," said a spokeswoman.

The estate also sells bulk wine to Matthew Clark, producers of Stowells of Chelsea bag-in-the-box wines. No one from the company was yesterday available for comment.

It also provides wines to up to 80 independent wine retailers across Britain, though a spokesman for the British office of the company was unable to say which.

"The most important thing to us is that at this stage these are merely allegations. The second is that they represent no threat to health and safety," thespokesman said.

This alleged malpractice could hardly have come at a worse time for the Australian wine industry, which has been hit hard by a poor vintage, especially in premium areas, at a time when its aggressive expansion programme has been paying off in the British market.

Latest figures show that Australian wine has leapfrogged over Italian wine into second place, behind France, with 13.5 per cent of the wine market in Britain. It was largely the demand on overseas markets for good-value Australian wines that had encouraged Kingston Estate in recent years to pursue a deliberate policy of expansion.

Unlike the traditional European countries, Australia has until now been scandal-free. This alleged malpractrice is likely to be seized on by the French, who have often claimed that Australia's success in the market is in some respects due to winemaking "tricks" such as irrigation and the addition of oak chips, both of which are legal practices.