The confectionery giant sought to save money and reduce wastage by introducing an "allowable tolerance level" for salmonella in its products, Birmingham Crown Court was told. Barry Berlin, prosecuting Cadbury on behalf of Birmingham City Council, described the change in 2003 as "utterly inappropriate".

Cadbury pleaded guilty earlier this year to breaching food and hygiene regulations in connection with the outbreak in the summer of 2006.

Mr Berlin told the court that until 2003 Cadbury had destroyed any chocolate which tested positive for salmonella, adopting an approach that "no amount of testing will make a positive result go away."

But the prosecutor added: "They then changed it to what they believed to be an allowable tolerance level. They (Cadbury) sought to save money from wastage by allowing a tolerance for salmonella in their food.

"Large quantities of product were being destroyed and Cadbury's were looking for ways of avoiding that and that's what they did. There is no dispute that there is a linkage between the chocolate that was distributed by Cadbury and the poisoning that took place later on."

Mr Berlin added that there was no safe level for salmonella cells in ready-to-eat products and that the organism could survive in chocolate for years. The court also heard that chocolate acted as a protective layer for salmonella organisms, shielding them from acid in the stomach.

Referring Recorder James Guthrie QC to research literature covering the subject of salmonella, Mr Berlin went on: "Cadbury knew perfectly well, we submit, that outbreaks of salmonella had been associated with very low levels in chocolate."

Cadbury has apologised for failing to realise a leaking pipe at its factory in Marlbrook, Herefordshire, posed a risk to health. The firm's barrister told a previous hearing that it had already spent £20 million on improvements, including changes to quality control procedures.

More than a million products were recalled by Cadbury on June 23 last year due to the outbreak. The Birmingham-based company was committed for sentence at the Crown Court after admitting offences at both Birmingham and Hereford magistrates' courts.