Proteus

A genus of enteric bacteria, Gram-negative facultative anaerobes with rod shapes, at home in soil, water, vegetables, shellfish, dairy products, and animal and human intestines. Certain members, notably Proteus vulgaris, spoil protein-rich foods such as eggs, meat, and fish, producing putrid odors and slime. Their presence in a food plant can signal sanitation gaps, since they thrive in moist residues on equipment. Identification relies on their vigorous urease activity and swarming motility on agar, traits that distinguish them from close relatives.