FIG 5.

Tolerance of biofilms to C&D regimes relevant in the food industry. The log₁₀ reduction upon C&D for multigenus biofilms and biofilms inoculated with seven L. monocytogenes strains grown on conveyor belt coupons is shown. Biofilms were allowed to develop undisturbed until day 4 before being cleaned with Alkalifoam and disinfected with either a QAC- or a PAA-based disinfection agent on four consecutive days. Calculated reductions are relative to control coupons rinsed in H₂O only. The L. monocytogenes counts in multigenus biofilms were determined by plating on selective agar. Mean values from five experiments and standard errors of the means are shown. Asterisks represent comparisons of samples using the two-tailed paired Student t tests. *, P = 0.06; **, P < 0.05.