(Stuff) - One of the UK's biggest supermarket chains withdrew two batches of imported chardonnay from sale this week because there was no warning on the label that the wine contained sulphites.

The same could happen here, because New Zealand works to much the same rules when it comes to protecting those most in need of protection from themselves.

Which in this case is a group of people, particularly asthmatics, who are allergic to these antioxidants and anti-microbial agents (call them preservatives if you like) that are added to wine to prevent it turning into vinegar.

For these people, drinking wine can lead most commonly to sniffing and sneezing or coughing but in more severe cases to tightness in the chest and difficulty breathing.

Headaches? Most unlikely.

Which means the number genuinely affected by sulphites probably represents about 1 per cent (some say up to 10 per cent) of the population.

Whether this includes those who are not completely intolerant and can consume small quantities of wine including sulphites nobody seems to know.

So for most of us the sulphite warning on the label is a non-issue, according to Malcolm Reeves who, as a senior lecturer in food technology at Massey University, was involved with the wine industry in its formulation of a wine standards management plan some years ago.

He is now a consultant winemaker and a visiting professor of wine science at the China Agricultural University in Beijing.

He says he was quite relaxed about New Zealand going with the sulphites warning, which was already mandatory in the United States where the danger of these preservatives to some people became an issue after a fast food chain sprayed salads with the preservatives to keep them fresh.

It has since been adopted in most wine-producing countries.

What concerns him now is the number of people who still don't know or haven't taken the trouble to find out what the sulphites warning on the wine they buy and drink is all about.