What kind of bacteria causes cheddar cheese to ripen?

Cheddar cheese ripening is primarily facilitated by bacteria such as Lactococcus lactis and Streptococcus thermophilus. These bacteria play a crucial role in the fermentation process, breaking down lactose and producing lactic acid, which helps develop the cheese's flavor and texture. Additionally, other bacteria like Propionibacterium freudenreichii may be involved in creating characteristic holes and enhancing the flavor profile during aging.