Five spore-forming bacterial strains were isolated as the most dominant microorganisms from five products of different types of cooked food. Three strains in particular were isolated as spoilage organisms causing acidity. These belonged to the genus Paenibacillus, and one of them was identified as Paenibacillus odorifer. All five strains grew at 10 degrees C in brain heart infusion broth; furthermore, four strains grew at 4 degrees C also. These strains grew optimally at 30 to 35 degrees C. Psychrotrophic Paenibacillus spp. can easily be mistaken for lactic acid bacteria in routine analysis because of their colony characteristics. Because the measures that must be taken for bacterial control are different in the case of contamination by these two bacterial groups, psychrotrophic Paenibacillus spp. contamination must be distinguished from that caused by lactic acid bacteria.