The widespread presence of Listeria in the food processing environment is a particular problem for the seafood industry. Listeria is a leading cause of food poisoning in the United States with a mortality rate of 20 percent to 30 percent, among the highest in food borne diseases.

What makes Listeria such a challenge is its ability to live in a wide range of conditions, including refrigerated temperatures that normally inhibit the growth of most bacteria. Routine cleaning and sanitation can fail to control the organism that thrives on processing equipment, conveyors, floors and drains. According to Ozone International in Bainbridge Island, Wash., many processors are adopting continuous sanitizing with ozone. The technology controls the bacteria growth and soil loading during production, significantly reducing the build-up normally seen at the end of the production day, the company says.

Ozone is continually sprayed onto conveyors, tables, slides and directly to the product during the production shift. Coupled with water intervention rinses during breaks and shift changes, seafood processing facilities can remain clean during production while affording the opportunity for the plant to go to extended or even continual production if necessary.

Bio-films are a particular source of recurrent Listeria contamination. Once bacteria form bio-films they become more resistant to cleaning and sanitizing treatment, and cells detaching from the bio-film can turn into a source of persistent contamination. Prevention is the key. Continual processing with ozone is an effective way to prevent bio-film formation, according to Ozone International. Some plants use ozone sprays on workers gloves, boots and aprons after breaks for further protection.