Removal of Salmonella biofilm formed under meat processing environment by surfactant in combination with bio-enzyme

- A two-step disinfecting hypothesis was put forward on biofilm removal of Salmonella.
- CTAB reduced more cells of biofilm (irreversible adhesion) than other surfactants.
- Cellulose removed more cells of mature biofilm than other tested bio-enzymes.
- A combination of cellulase following by CTAB immersion can remove all biofilm.

Salmonella outbreaks are commonly linked to consumption of contaminated food, its outbreaks have been associated with the biofilm formed on food processing surfaces, due to the acquired resistance that this bacterium possesses. In this study, four surfactants and five bio-enzymes were individually and conjunctively tested to remove the biofilm formed on stainless steel surfaces by a seven-strain cocktail of Salmonella grown in meat thawing-loss broth (MTLB). The results showed that cetyltrimethyl ammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) reduced greater numbers of biofilm cells than tween-80 and rhamnolipid. 1 mg/mL of CTAB and 10 mg/mL of SDS could remove 100% cells of biofilm at irreversible attachment phase (about 5.39 Log CFU/cm2). Compared to proteinase K, dispaseⅡ, glucoside amylase and subtilisin, cellulase reached greater reduction (85%, about 5.6 Log CFU/cm2) of cells in mature biofilm, but still remaining a huge number of residual biofilm cells. The combination of cellulase following CTAB immersion was effective in removal mature biofilm (100%, about 6.2 Log CFU/cm2 cells), which was supported by the observation of fluorescence microscopy. This study indicated that CTAB combined with cellulase can apply as an alternative strategy to drastically remove mature biofilm of Salmonella exposed to meat processing environments.