Biofilm development by Listeria innocua in turbulent flow regimes

Cells of Listeria innocua grown in continuous culture were recirculated through stainless steel tubes at Reynolds numbers ranging from 9500 to 16,500 for 7 days. Samples of the tubes were removed by a special method and were examined using SEM. Biofilm formation had occurred after only 1 day at Reynolds numbers of 9500 and 11,500 and the extent of coverage increased with time. At the higher Reynolds numbers (13,000 and 16,500) only individual cells were evident after 1 day, but these were developed to form microcolonies. After 7 days biofilms had become established at all four Reynolds numbers.