Neutral Red Chalk Lactose Agar is recommended for the detection of lactic Streptococci in milk and milk products. Neutral Red Chalk Lactose Agar is used for the detection of lactic Streptococci in milk and milk products. Lactic Streptococci are normally present in milk and are also used as starter cultures in the production of cultured dairy products. A starter culture can provide particular characteristics in a more controlled and predictable fermentation.