According to a report published today (4 July) by the Food Standard Agency's expert advisory committee, the testing system employed by Cadbury Schweppes to check for salmonella is outmoded, unreliable and underestimates the threat of contamination.

As part of its investigation into salmonella contamination that led to Cadbury's recall of seven own-brand chocolate products, including the iconic Dairy Milk chocolate bar, an emergency meeting of the independent Advisory Committee on Microbiological Safety of Food (ACMSF) identified a number of serious flaws in Cadbury's food safety procedure.

The expert committee said that end-product testing, which is the norm at Cadbury, is unsuitable for guaranteeing the safety of food. "In order to give assurance about the absence of salmonella or any other pathogen in food a prohibitively large amount of product would need to be tested. However, even this would not guarantee absence of the micro-organism," the report stated.

"Based on the information provided, Cadbury appears to have used methods for product testing which the committee considered would underestimate the level and likelihood of salmonella contamination," the ACMSF stated.

Cadbury's most probable number (MPN) approach was described as "unreliable" by the expert committee, because sample heterogeneity influences the MPN estimate.

Cadbury has recalled more than one million chocolate bars because the chocolate crumb, a base ingredient used in their production, was contaminated with salmonella Minerva. The committee noted that, to date, only seven brands have been recalled. However, the chocolate crumb was used in the production of an additional 30 products over a three-week period.  "Where contaminated chocolate crumb was used in the manufacture of products other than those recalled, there could also be a cause for concern," the committee commented. However, the committee acknowledged that it was difficult to quantify the risk.

Cadbury has come under fire from the FSA because it failed to notify the agency of the problem until two weeks ago, despite the fact that it was aware of the salmonella contamination in January.

The company delayed, Cadbury has said, because levels of contamination were so low as to not represent a threat to public health. However, the independent experts presented a different view:

"Cadbury's risk assessment assumes that a threshold for infection can be estimated from previous outbreak data on levels of micro-organisms in chocolate. Such a threshold is not the same as the minimum infectious dose for salmonella in chocolate; no minimum infectious dose can be defined and infections may occur in consumers exposed to significantly lower levels than that seen in previous outbreaks.

"Cadbury's risk assessment does not address the risk of salmonella in chocolate in a way which the ACMSF would regard as a modern approach to risk assessment," the ACMSF warned.

Cadbury spokesperson Tony Bilsborough told just-food that the company has taken on board these criticisms.

"We have acted in good faith and we do not challenge the views of the expert committee advising the FSA or the EHOs. We agree that it's the job of the FSA and EHOs to provide guidance on these matters and we welcome their advice.

"We'll continue our dialogue with the regulators and will be improving our procedures in the light of their advice. However, we welcome the confirmation by the FSA that they believe 'proportionate action was taken by recalling the seven products,'" the company said.