Trading standards officers will launch an investigation this week to determine whether Cadbury should be prosecuted over the salmonella contamination of some of its products.
A spokesman for the Food Standard Agency said an inquiry would determine whether the Birmingham-based confectionery giant had breached the Food Safety Act in terms of hygiene and its failure to inform it when tests identified the contamination threat five months ago.
On Friday, Cadbury announced a mass recall of more than a million of its chocolate bars after contamination was detected at one of its main factories in Marl-brook, Herefordshire.
The Bournville-based company sent samples to an external laboratory in January, which were then sent to the Health Protection Agency for further testing.
Some of the samples were found to contain the rare strain salmonella montevideo, and it was traced to a leaking pipe at the Marlbrook plant.
But the laboratory findings only came to light when the HPA noticed a surge in the number of salmonella montevideo cases over the last four months.
Cadbury insisted there was no link between the food poisoning outbreak and the mass contamination of its products with the same bacteria.
But the Health Protection Agency would not rule out a link between the recall and a quadrupling of cases of the
montevideo salmonella strain over the last four months.
A spokeswoman for the HPA said there had been 45 cases of the rare strain over the last four months, compared with just 12 over the same period last year, including a significant rise among children.
There was no evidence this was linked to the Cadbury contamination, she said, but added: "If the number of cases reported to us does decline it will be stronger evidence of a link with confectionery products."
A spokesman for the Food Standards Agency said Cad-bury should have reported the salmonella findings to it when it was discovered in January.
"We would have expected them to contact us and we were surprised they did not contact us sooner," he said. "Last week was about recalling the chocolate. "Now we will get as much detail as possible to see if there is a case to answer. "As far as ready-to-eat foods - such as chocolate bars - salmonella contamination is not acceptable and that is why we would have expected to be told in January."
He said environmental and trading standards officers from Herefordshire Council would be going to the factory this week to investigate.
"We will also look at any action they were supposed to take such as informing us and seeing if they should have conducted a withdrawal.
"Trading standards officers from Herefordshire will have responsibility to inspect the company and get to the bottom of what actually happened."
Meanwhile, a marketing and brand expert at Warwick University said Cadbury would ride out the storm.
"There may be a small minority of more aware parents who don't want their kids to eat Cadbury's chocolate, but the loyalty to the Cadbury among consumers is very high because of very clever brand building work," said Dr Lyndon Simkin.
"They have very homely adverts and consumers have a very, very strong affinity with it and trust in it.
"They will have to say a big sorry to some of their retailers and perhaps discount some of their merchandise to them for a few months."