Case Study: Listeria Control in a Ready-to-Eat Food Facility

Listeria monocytogenes' ability to survive in extreme conditions and form biofilms on various surfaces is a significant challenge for food safety. Last week, members of our Decontamination Service team helped a ready-to-eat food facility win the fight against l. monocytogenes. Treating an area just shy of 1,000,000 ft3, the service team completed the decontamination in just two days thanks to a very helpful in-house staff.  The first day consisted of sealing the space from the surrounding areas and sealing the ventilation system off at the roof.  Chlorine dioxide gas generators were setup with tubing run to various locations within the space to speed up the natural gas distribution.  50 biological indicators, all containing over a million bacterial spores, were placed at locations chosen by the facility's Quality Assurance and Food Safety personnel.  The decontamination itself took place on the second day, with gas concentrations being monitored continuously throughout the process from multiple locations throughout the space.  Once the final sampling location eclipsed the target dosage, the decontamination was deemed complete, and the gas was aerated from the facility.  Once the gas was removed and the area was safe for reentry, our team retrieved our supplies and packed them up.  Biological indicators were recovered and processed the next day to check for growth.  After 36 hours of incubation, all biological indicators were negative for growth, capping off a successful decontamination.