The British Sandwich Association said it is unlikely the suppliers of sandwiches that may have contained listeria are to blame for the deaths of five hospital patients across the UK.
Director Jim Winship told talkRADIO’s Mike Graham the “tiny traces” of listeria that may be in a packaged sandwich when it leaves the factory are unlikely to affect anyone.
“It’s very unlikely that the amount of listeria that was in the sandwiches was particularly high when it left the factory,” he said.
“If sandwiches and chilled foods are left out in very hot environments the bacteria will grow.”
Mr Winship said doctors and hospital workers should consider whether patients can handle the small amounts of listeria that may remain on sandwiches despite "clinically clean" factory practices.
“The only people who are vulnerable from listeria are people who’ve got suppressed immune systems - in other words seriously ill in hospital - or are pregnant and identified as being at risk,” he said
“Most of those won’t be affected by it anyway.”
He said he is in talks with the Food Standards Agency to prevent this happening again.
The NHS has identified nine confirmed cases of listeria at seven different hospitals across the country.
Five people are suspected to have died after eating pre-packaged sandwiches and salads linked to supplier The Good Food Chain.
In a statement The Good Food Chain said it has voluntarily ceased production and is co-operating “fully and transparently” with authorities.
The business was supplied with meat from North Country Cooked Meats, which has since tested positive for listeria and stopped production.
The Good Food Chain said the underlying cause of the outbreak remains unclear.
Health secretary Matt Hancock has promised “severe consequences” if caterers and hospitals have failed to meet safety standards.