[Histamine formation by Proteus species in tunafish (author's transl)]

Introducing the authors report on cases of scombroid poisoning episodes in food serving establishments. These cases were related to the formation of histamine in tuna meat due to Proteus morganii although the meat was sound when taken from cans. It is demonstrated experimentally (Table 1) and shown in a critical literature review (Table 2) that among Proteus species Proteus morganii is the only species being able of producing histamine levels high enough to cause food poisoning in humans. Multiplication and histamine formation by Proteus morganii at different temperatures show (Fig. 1 and 2) that the concentration of histamine increases rapidly once the formation has started and the level of 1000 mg/kg considered as critical may be exceeded within a short period of time. These results confirm our observations obtained during epidemiological studies of food poisoning cases that improper handling and storage of tuna meat from cans at food serving establishments may bear the risk of causing scombroid poisoning. It should be emphasized that certain cultures of Proteus morganii are able to form histamine at levels of more than 1000 mg/kg even at a temperature of 7 degree C although prolonged incubation is necessary (Fig. 1). This fact should be taken into consideration in the evaluation of results when a prolonged period of time has elapsed between sampling or consumption of the suspect food and its examination.