Food processing faces salmonella risk

The research suggested that once salmonella bacteria gets into a food processing facility, and forms a biofilm on its surfaces, it is likely to be difficult, if not impossible, to destroy.

“We found that it was not possible to kill the Salmonella cells using any of the three disinfectants, if the biofilm was allowed to grow for seven days before the disinfectant was applied,” said Mary Corcoran, a researcher on the study.

A lot of the time, the disinfectant may add very little, if anything, to good cleaning and appropriate food handling practices

Mary Corcoran

“Even soaking the biofilms in disinfectant for an hour and a half failed to kill them.”

The impetus for the study, conducted by researchers from the National University of Ireland, Galway, was a European outbreak in which 160 people in 10 countries became ill from the Agona serotype of salmonella – an outbreak that was traced to meat from a major food-processing facility.

Corcoran suggested that the research did not uncover anything special about the Agona strain of salmonella, rather it uncovered the fact that all types of salmonella were able to adopt the specialised biofilm lifestyle – whether the surface was glass, stainless steel, glazed tile or plastic.

The warning to process facilities is to take stricter care to keep salmonella out of the clean areas where cooked foods get further processing and packaged.

“People need to question whether disinfectants that are promoted as killing various types of bacteria are really as effective in real life situations where biofilms can form as they are claimed to be based on experiments that do not use biofilms,” said Corcoran.

“A lot of the time, the disinfectant may add very little, if anything, to good cleaning and appropriate food handling practices. There is a need for more research to define better methods for killing salmonella biofilms.”