Its key features will be a more reliable database, bar-coding of samples, and a much faster turn-round of results.

Producers and their vets should be able to go on-line a fortnight after pigs have been sampled to get the results.

“We've got new salmonella regulations coming in from Europe next year and we have got to make the scheme work better,” said ZAP coordinator Veronica Wright today.

To date, ZAP has achieved no reduction of salmonella levels in England.

This is partly because the current scheme is unwieldy and prone to human error, but mainly because many pig-keepers, and their vets, are sceptical about its effectiveness.

One pig-keeper asked his vet what he should do about his ZAP results and was told, “Don't worry about it. Put them in the bin.”

“As a result of attitudes like this we have been trying hard to get all the vets engaged with the new scheme,” said Veronica Wright.

One of the reasons vets were sceptical was that results didn't reach producers until they were six weeks – or more – out of date, and were therefore of little value.

ZAP levels will stay the same for the time being – 50 percent or over for ZAP 2 and 65 per cent or over for ZAP 3.

But these levels are likely to be stiffened up in the future because ZAP levels won't come down significantly unless those in ZAP 1 make an effort.

When a pig-keeper is in ZAP 2 or 3 he will be expected to request a visit by the Veterinary Laboratories Agency – or he can use his own vet if he prefers – and to introduce an action plan to get levels down.

He will then have 16 months (ZAP 2) or ten months (ZAP 3) to reduce salmonella levels.

If after diligently attempting to reduce levels a pig-keeper has made no headway, the Veterinary Laboratories Agency may look at what else can be done. It may want to investigate the health status of weaners coming onto the farm.

No pig-keeper will be suspended from his assurance scheme if he is genuinely focussing on reducing salmonella, says Veronica Wright.

With the introduction of the new web-based database, the new ZAP scheme will be much less prone to error and will require less human intervention.

There will be a simple system, for instance, to ensure batch producers don't miss sampling windows.

But the scheme still has one significant challenge – it must encourage pig-keepers and vets to go the extra mile to reduce salmonella, even if there are no penalties.

In Denmark financial penalties are imposed on pig-keepers who don't reduce their scores to an acceptable level. Such a system might be susceptible to legal challenge in Britain.

One thought is that abattoirs could pay more for pigs from ZAP 0-1 units and less for pigs from Zap 2-3 units. But nothing has been decided.