An Orange-Reddish Pigmentation in Roquefort Cheese

Abstract

The presence of an anomalous orange-reddish coloration in Roquefort cheese during its ripening period was studied. No pigmented colonies were isolated from milk, curd, or cheeses after pressing, but their presence in relatively large numbers was observed after salting (7 d) up to the end of the ripening process (90 d). About 37% of the strains isolated (32 in all) were orange-pigment producers in light as well as in the dark (type I), whereas about 25% produced an orange coloration only in the light (type II). No production of pigment was observed at pH 6.0 or below in the absence of sodium chloride, and the highest color intensity was registered at pH 7.0 in the presence of sodium chloride. Morphological and physiologic studies of the orange-pigmented strains revealed that most of them were closely related to Brevibacterium linens.