On Food and Cooking

other cheeses, is Brevibacterium linens. As a
group, the brevibacteria appear to be natives
of two salty environments: the seashore and
human skin. Brevibacteria grow at salt
concentrations that inhibit most other
microbes, up to 15% (seawater is just 3%).
Unlike the starter species, the brevibacteria
don’t tolerate acid and need oxygen, and grow
only on the cheese surface, not inside. The
cheesemaker encourages them by wiping the
cheese periodically with brine, which causes a
characteristic sticky, orange-red “smear” of
brevibacteria to develop. (The color comes
from a carotene-related pigment; exposure to
light usually intensifies the color.) They
contribute a more subtle complexity to
cheeses that are wiped for only part of the
ripening (Gruyère) or are ripened in humid
conditions (Camembert). Smear cheeses are
so reminiscent of cloistered human skin
because both B. linens and its human cousin,
B. epidermidis, are very active at breaking