Figure 1.
Populations (log CFU/cm2) of biofilm cells on SS coupons, just before disinfection.
(A) L. monocytogenes; (B) P. putida. Biofilms were left to be formed on coupons incubated at 18 °C for a total period of 10 days in daily renewable TSB, under either mono-species (□, three strains of each one species together), or dual-species conditions (■, six strains of the two different species together) and subjected daily to disinfection (6-min exposure to 50 ppm of BC solution). The bars represent the mean values ± standard deviations (n=6, two independent experiments, each performed three times). For each graph separately, mean values sharing at least one common lower case letter shown above the bars are not significantly different at a P value of <0.05.
Figure 2.
Log reductions (log CFU/cm2) of biofilm cells on SS coupons, following disinfection.
(A) L. monocytogenes; (B) P. putida. Biofilms were initially left to be formed on coupons incubated at 18 °C for a total period of 10 days in daily renewable TSB, under either mono-species (□, three strains of each one species together), or dual-species conditions (■, six strains of the two different species together) and subjected daily to disinfection (6-min exposure to 50 ppm of BC solution). The bars represent the mean values ± standard deviations (n=6, two independent experiments, each performed three times). For each graph separately, mean values sharing at least one common lower case letter shown above the bars are not significantly different at a P value of <0.05.
Figure 3.
Percentages of viable L. monocytogenes (filled bars) and P. putida (open bars) cells in the dual-species biofilms.
(A) Just before disinfection; (B) Following disinfection. Dual-species biofilms were initially left to be formed on SS coupons incubated at 18 °C for a total period of 10 days in daily renewable TSB and subjected daily to disinfection (6-min exposure to 50 ppm of BC solution).
Figure 4.
Percentages of killed L. monocytogenes (filled bars) and P. putida (open bars) cells in the dual-species biofilms.
Dual-species biofilms were initially left to be formed on SS coupons incubated at 18 °C for a total period of 10 days in daily renewable TSB and subjected daily to disinfection (6-min exposure to 50 ppm of BC solution).
Figure 5.
Percentages of viable cells for each strain in the mixed-culture biofilm communities.
(A) L. monocytogenes; (B) P. putida. Mixed-culture (mono-/dual-species) biofilms were left to be formed on SS coupons incubated at 18 °C for a total period of 10 days in daily renewable TSB and subjected daily to disinfection (6-min exposure to 50 ppm of BC solution). Graphs present the distribution of viable strains in the mono-species biofilm communities (the 1st day of incubation), as well as in the dual-species biofilm community (the 10th day of incubation), just before and after disinfection.