Purpose: The objective of this study was to investigate the transfer rate of L. innocua biofilm cells from food contact surfaces to food and the growth potential of biofilm cells on foods.
Methods: Listeria innocua biofilms were formed on four kinds of materials (rubber, polypropylene, glass, and stainless steel), which were put in contact with cooked duck meat (boiled or baked) for five min. Cooked duck meat with transferred biofilm cells was stored at 4°C and 10°C. The growth of biofilm and planktonic cells on cooked duck meat were compared. The viability of biofilm cells formed on food contact surfaces and of transferred cells to duck meat were also confirmed by fluorescence microscope.
Results: The highest transfer rate of L. innocua biofilm cells was observed in the polypropylene material and the lowest was in the stainless steel material, regardless of the cooking method of duck meat. The viability of transferred biofilm cells to duck meat was confirmed. Although the lag time of biofilm cells was delayed compared to planktonic cells, the transferred biofilm cells were observed to grow to the maximum population density.
Significance: Biofilm cells from food contact surfaces transferred to food due to cross-contamination and the possibility of growth can be a risk at foodservice industry. Thus, it is important to apply an effective sanitizing step to prevent and reduce the biofilm formation on food contact surfaces during food preparation.