Studies on the role of halophilic bacteria in the process of histidine decarboxylation in fish muscles (15,22) have been carried out at the Department of Food Hygiene and Public Health, Faculty of Veterinary Medicine, since 1991. As part of these studies, strains of halophilic bacteria were isolated from salted herrings, and their ability to produce histamine by decarboxylation of histidine was proved under model conditions according to the method described by Karnop (12). Our own modification consisted of an increased amount of NaCl added to the nutrient broth. It was revealed that all bacteria isolated from herrings are able to multiply and produce histamine in an environment containing both 8% and 20% NaCl (2,17,18,21). Out of the isolated halophilic bacteria, one strain, marked as strain 3b, had an exceptionally high ability to produce histamine by decarboxylation of histidine (3,21). Strain 3b was counted among the Pseudomonas beijerinckii species, isolated for the first time from salted beans by Hof in 1935 (10). The reference strain of Pseudomonas beijerinckii (type strain DSM 72l8 l = ATCC 19372 T = NCIMB 9041 1 ) and strain 3b were subjected to more detailed investigations. The analysis of the 16S rRNA gene sequences, phenotypic properties, and similarities in the composition and profile of fatty acids pointed to both strains (reference and 3b) belonging to the same genus Chromohalobacter, family Halomonadaceae (1). In view of the results obtained, it seemed appropriate to reclassify Pseudomonas beijerinckii and recognize it as Chromohalobacter beijerinckii (20).Chromohalobacter beijerinckii strain 3b belongs to the psychrophilic bacteria, which can grow at temperatures between 5°C and 42°C (20) and with a NaCl content of 0.5% to 25.0%, and which tolerate a pH value between 4.5 and 8.0. The presence of salt is a factor that determines both the growth of that strain and its