Effect of Lactic Starter Culture on Pink Discoloration and Oxidation-Reduction Potential in Italian Cheese

Abstract

Fifteen cultures of high-temperature streptococci and lactobacilli were evaluated for their effects on development of pink discoloration in Romano cheese. Certain strains of lactobacilli used as starter cultures were found to be consistently associated with appearance of the discoloration, whereas other strains, and strains of Streptococcus thermophilus, never caused the defect. Using a combination of S. thermophilus together with defect-producing Lactobacillus strains resulted in a delayed appearance of discoloration. Cheese made with cultures associated with the discoloration always had a higher oxidation-reduction potential, as indicated by neutral red indicator, 48 hr after manufacturing. Cheese made with cultures not associated with the defect had a lower oxidation-reduction potential at this stage of curing. Development of pink discoloration was accelerated by higher curing temperatures and appeared to be enhanced by penetration of oxygen into the cheese but not by absorption of sodium chloride by the cheese. © 1969, American Dairy Science Association. All rights reserved.