THE hunt is on for packs of butter linked to the listeria food poisoning bug.
Ten catering-size containers made by J & E Dickinson at Longley Farm, Holmfirth, have still to be traced.
The withdrawal of batches of 2kg packs of Longley Farm Dairy Butter in connection with listeria cases was revealed by the government's Food Standards Agency.
Three people in Huddersfield, all over 80, have died since last October and a further three were treated in hospital. So far this year a total of 29 people have fallen victim in Yorkshire and Humberside.
Twelve of them have been linked to the butter, but the Health Protection Agency was unable to say if this included the three Huddersfield deaths.
Tests by environmental health officers revealed listeria in some batches of butter made by Longley Farm that had passed their "use by" date.
The company said the 2kg containers were likely to have been used by commercial customers in canteens, cafes and sandwich bars.
Several hundred packs have been traced but about 10 are believed to be still outstanding.
The dairy firm - which employs 130 workers - said today no traces of listeria had been found in any of its butter since May 17.
A statement said the Government's Health Protection Agency had given the all-clear on its operations and equipment in a report in mid-June.
Jim Dickinson, owner of the farm, said: "We have made every effort from day one to monitor and maintain the highest standards. We have also co-operated fully with the relevant agencies and acted on the advice of the environmental health officers.
"We want to avoid any possibility of a risk to public health."
The dairy processing business has been in existence for 55 years and the firm said it had never had a previous incident of bacterial contamination.
Kirklees Council said Longley Farm had co-operated with its officers and promptly introduced additional hygiene and cleaning measures.
A council spokesman said: "As a further precaution, daily samples have been taken and a positive release system has been implemented.
"All samples have been negative since the additional hygiene measures were introduced."
Dr Ruth Gelletlie, of Yorkshire and Humberside Health Protection Agency, said the agency had been working closely with local authorities to investigate listeriosis cases in the region this year.
"This follows a significant increase in the number of cases this year, with 29 cases seen so far, compared to 12 cases for the whole of 2002," she said.
"We have looked closely at all the cases which have occurred and 12 of the cases were found to have been caused by one particular strain of listeria. The other cases are ass- ociated with a number of other listeria strains.
"A particular food product has been linked to some of these cases."
Investigations were continuing to try and identify any other common factors to the cases, she said.
* Any customer with concerns should contact Longley Farm on 01484 684124.