Penicillium roquefortii is a common fungus that can be isolated from many sources--mostly organic or humus sources. This fungus is a saprobic organism belonging to the fungi imperfecti classification. P. roquefortii has many different industrial uses, for example, flavorings, proteases, antibacterial agents, polysaccharides, and, most well known, blue cheeses. In general, P. roquefortii is safe to use as flavorings and for cheese. This fungi does, however, produce many mycotoxins. These mycotoxins are strong, but not stable. The FDA says that blue cheese is safe for human consumption, and does not really pose a threat to humans, unless the person has an allergy to the mycotoxins. Even though the fungus on cheese seems to be safe for human consumption, many workers in factories dealing with P. roquefortii have had severe respiratory problems. These cases, however, are infrequent and seem to affect older or weakened workers.