Daily chewing of gum containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) or xylitol can significantly reduce the level of Streptococcus mutans bacteria in saliva. A study of 60 participants who chewed gum containing either CPP-ACP or xylitol for 3 weeks found that both reduced S. mutans, but CPP-ACP gum reduced levels more than xylitol gum. CPP-ACP and xylitol have properties that inhibit the growth and attachment of S. mutans to teeth, thereby reducing the risk of dental caries.