The filamentous fungus Monascus sp. has been widely used as an
enzymatic agent to produce fermented food products in Asian
countries. The main Monascus fermented products are Monascus
pigments which have been used as natural food additives. Monascus
pigments are also recognized as one of the potential food
colorants in European Union and United States (1). Monascus pigments
are reported to prevent cancer, decrease blood sugar levels,
and exhibit anti-inflammatory and anti-tumor properties (2),
which are also successfully employed as total or partial substitutes
of nitrate and nitrite salts in coloration, flavoring and preservation
of red meat (3). Monascus pigments were considered as safe food
coloring agents until citrinin, a nephrotoxic mycotoxin, was
detected in Monascus products (4). The creation of citrinin rules out
the use of the Monascus pigments in food production and processing.
It was reported that citrinin could cause 50% cell death to
human embryonic kidney cell in a range of 1.8e4.7 mg/mL (5). In
the field of food safety, citrinin concentration is limited officially to
0.2 mg/L in Japan, and the standard of specification on the citrinin
concentration for functional food products should be less than
2 mg/L in Taiwan (6).
Citrinin and pigments biosynthetic enzymes are regulated
independently (7), allowing the prevention of citrinin formation
during pigments production by process control. Pigments and
citrinin synthesis depend on the Monascus strain (8), carbon source