Which of the following is used in the production of bread?

Assertion $(A)$: Consumption of buttermilk after a meal is beneficial.
Reason $(R)$: $LAB$ (Lactic Acid Bacteria) protects the stomach from harmful bacteria.

Statement $P$: $LAB$ is used to make bread.
Statement $Q$: $Lactobacillus$ is used to make curd.

The starter or inoculum is added to fresh milk in order to convert milk into curd. The term starter or inoculum here refers to:

Which organism is used to ripen Roquefort cheese?

Which processes are involved in the activity of $Lactobacillus$ bacteria?