Recreating pink defect in cheese with different strains of Thermus bacteria

Pink discoloration defects in cheese manifests as the appearance of pink patches within cheese blocks and has recently been associated with Thermus thermophilus. Swiss-type cheeses were prepared at pilot scale using thermophilic starter cultures, Propionibacterium freudenreichii, and one of Thermus thermophilus HB27, Thermus scotoductus SE1 or Thermus thermophilus DPC6866 or a control without Thermus. Significantly, a higher level of redness was observed in cheeses with Thermus thermophilus HB27 relative to the other cheeses and suggests that the development of the pink defect is dependent on the strain of Thermus present and on other, as yet unknown, factors that require further study.