Sam WilliamsContamination led to the closure of part of the city's Colman's factory in the run-up to Christmas, it emerged today.Sam Williams

Contamination led to the closure of part of the city's Colman's factory in the run-up to Christmas, it emerged today.

Routine tests at the historic Carrow plant found microbiological contamination in a 'small number' of batches of products made in an area called the Guinness department, which makes seasonings and sauces.

Claims the products were contaminated with E-coli have not been confirmed by parent company Unilever, which stressed none of the affected items were sent to retailers and were destroyed.

The affected department was closed for five days while an investigation was carried out to determine the source of the contamination.

Officials at Unilever were also unable to confirm whether or not the source had been identified.

The majority of the Norwich plant was not affected by the contamination and the Guinness department returned to full operation before Christmas, the company said.

A Unilever spokesman said: "Routine quality tests discovered a low level of microbiological contamination in a small number of batches of products made at our Norwich factory.

'Our strict product safety and quality procedures ensured that no affected product was sent for distribution to retailers. The small amount of product affected has been destroyed after a full investigation.

'Production restarted before the Christmas break and is continuing normally."

Colman's, one of the country's oldest existing food brands, was founded in 1814 by Jeremiah Colman and moved to the current site at the bottom of Bracondale in 1865.

The firm was bought by food and household brands giant Unilever in 1995.

In November last year industrial action was averted at the Colman's plant when the parent company offered workers an improved pay offer.

Do you have a business story for the Evening News? Call senior business writer Sam Williams on 01603 772447 or email sam.williams@archant.co.uk