F4
For autoaggregation analysis, LAB were individually cultivated in MRS broth for 18 h and centrifuged (8000 × g), and E. coli F4 in BHI broth, following the same protocol. The pellets were washed twice in 0.9% saline solution, and samples containing 1 × 108CFU/mL in 0.9% saline solution were prepared. The samples were homogenized and incubated at 37 ºC for 5 h and, every hour, 1 mL of the supernatant was collected, and the optical density (OD) was evaluated in a spectrophotometer at 600 nm. Autoaggregation was calculated as follows, where AA (%) refers to the percentage of autoaggregation, OD0 at initial OD600nm, and ODt at OD600nm checked every hour:
\begin{equation} \text{AA\ }\left(\%\right)=\left(\frac{\text{OD}_{0}-\text{OD}_{t}}{\text{OD}_{0}}\right)*100\nonumber \\ \end{equation}
Coaggregation analyses were performed following the same protocol, with co-cultivation of each LAB and E. coli F4, with OD being measured every hour for 5 hours. Coaggregation was calculated as follows, where CA (%) refers to the percentage of coaggregation, OD0bthe initial OD600nm of the LAB, OD0e the initial OD600nm of E. coli F4, and ODb+e the OD600nm of the co-cultivation hourly in co-cultivation:
\begin{equation} \text{CA\ }\left(\%\right)=\frac{\left[\frac{\text{OD}_{0b}+\ \text{OD}_{0e}}{2}-\text{OD}_{b+e}\right]}{\frac{\left[\text{OD}_{0b}+\text{OD}_{0e}\right]}{2}}\ *100\nonumber \\ \end{equation}