Histamine-forming Bacteria Research Articles

好塩性ヒスタミン生成菌のヒスチジン脱炭酸活性に及ぼす反応条件の影響

好塩性ヒスタミン生成菌のヒスチジン脱炭酸活性に及ぼす反応条件の影響

海産魚における耐塩性及び好塩性ヒスタミン生成菌の分布ならびに同菌による不揮発性アミン生成

海産魚における耐塩性及び好塩性ヒスタミン生成菌の分布ならびに同菌による不揮発性アミン生成

海産魚における低温性ヒスタミン生成菌について

海産魚における低温性ヒスタミン生成菌について

耐塩性および好塩性ヒスタミン生成菌に関する研究‐ＩＩ 市販赤身魚加工品における耐塩性および好塩性ヒスタミン生成菌の分布

This study was carried out to investigate halotolerant and halophilic histamine-forming bacteria in red meat fish products. Forty-six isolates of halotolerant and halophilic histamine-forming bacteria were isolated from 35 samples out of 133 red meat fish products. Twenty-three isolates, 20 isolates, and one isolate out of 46 histamine-forming bacteria were identical with Staphylococcus, Vibrio, and Pseudomonas III/IV-NH, respectively. The two remaining isolates were unidentified. Forty isolates produced 40-100mg/100ml of histamine in the histidine broth added to 10-15% NaCl after 14 days at 20°C.

市販いわし糠漬けからの耐塩性ヒスタミン生成菌の分離

This study was undertaken to find the salt tolerant histamine-forming bacteria in commercial rice-bran pickles of sardine. Eight isolates of histamine-forming bacteria were found in the rice-bran pickles of sardine and shown to be salt tolerant bacteria and mesophiles. Five out of the 8 isolates were nonhalophiles. Especially, 2 out of these 5 isolates produced large amounts of histamine. All isolates were cocci, Gram positive, and non-motile bacteria. They were identified as Staphylococcus biologically. A remarkable histamine producer, strain No. 7 was mixed into a histidine broth added with 10% and 12% NaCl. The histamine level reached 100mg/100ml after 3 days at 37°C. Strain No. 7 seemed to be related to the accumulation of histamine in commercial rice-bran pickles of sardine.

東京湾および相模湾沿岸海水における中温好塩性ヒスタミン生成菌の季節的消長

Seasonal variation in numbers of histamine-forming bacteria was investigated for a one year period in the water samples collected bimonthly from 3 inshore stations in Tokyo Bay and Sagami Bay. Histamine-forming bacteria isolated from these water samples by using histidine broth were classified into 3 types in respect to growth-temperature/salinity: psychrophilic halophitic group, mesophilic halophilic group, and nonhalophilic group. Psychrophilic halo-philic group bacteria were found at the level of 10-102/10l from autumn to the following spring. Mesophilic halophilic group bacteria were detected 10-103/10l from early summer to autumn when water temperatures rose above 20°C. From the taxonomic characteristics, psychrophilic halophilic histamine-forming bacteria were identified with N-group bacteria. But mesophilic halophilic histamine-formers, which can produce as much histamine as Proteus morganii can, could not be identified with any known species.

市販鮮魚における好塩性ヒスタミン生成菌の季節的消長

Seasonal variation in the number of halophilic histamine-forming bacteria on/in marine fish and changes in their number on marine fish stored at 25°C were studied. Psychrophilic halophilic histamine forming bacteria (N-group bacteria) were detected from viscera and skin of fish throughout one year. Besides these mesophilic halophilic histamine-forming bacteria, which were thought to be a new species, were isolated from mackerel during May and July, and from horse mackerel in June, July, September, and November. The occurrence of these bacteria showed similar seasonal variations to that in sea water reported in our previous report. During storage of mackerel at 25°C, both types of halophilic histamine-forming bacteria increased in the fish muscle, they could be detected at a cell count of 10-103/g after 16h of storage. Histamine concentration in the muscle after 24h storage increased to become 70-120mg/l00g. This suggested that these new mesophilic halophilic histamine-formers, along with N-group bacteria, were responsible for the scombroid poisoning.

Occurrence of Allergy-like Food Poisoning Caused by “Mirin”-Seasoned Meat of Dorado (Coryphaena hippurus)

Portions of meat with a pungent and bitter taste found in “mirin”-seasoned dorado were considered to have been responsible for an outbreak of food poisoning in Yokohama in 1984. In this study the substance responsible was analyzed. The concentration of volatile basic nitrogen and viable counts of total bacteria were low in the toxic fish meat samples implicated in the food poisoning as well as in control fish meat, but the pH values were higher than that of the control, and the histamine content was 107 to 195mg/100g, which is higher than the amount causing allergy-like food poisoning. Cadaverine was found at concentrations of 17.3 to 20.8mg/100g in the toxic meat. The pungent and bitter tastes of the toxic meat were considered to be due to histamine and cadaverine, respectively. The viable counts of histamine-forming bacteria in the toxic meat were too low to account for the production of a large amount of histamine. The activity of histidine decarboxylase was found to be much higher in the toxic meat than in the control meat.

Densities and characteristics of histamine-forming luminous bacteria of marine fish

Densities and characteristics of histamine-forming luminous bacteria of marine fish

Bacterial decomposition of carnosine and its methyl derivatives.

Seventeen strains of bacteria isolated from the putrefied meats of the sei whale and mackerel were incubated in the media containing balenine, and it was found that they are able to hydrolyze balenine in a greater or lesser degree. Among 68 strains of histamine-forming bacteria isolated from the sardine and mackerel, on the other hand, only 2 strains showed the hydrolyzing activities on carnosine or anserine when incubated in media having these imidazole dipeptides. β-Alanyl-histamine and its methyl derivatives which correspond to the decarboxylation products of carnosine and its methyl derivatives were not detected throughout the experiments.

Occurrence of various histamine-forming bacteria on/in fresh fishes.

In the previous paper, the authors reported on the occurrence of N-group bacteria (psychrophilic-halophilic histamine-forming bacteria) on/in red meat fishes. The present study was undertaken to obtain further information as to the occurrence of the histamine-forming bacteria known, in addition to N-group bacteria on/in fresh fishes. The histamine-forming bacteria found in the thirteen red meat fish samples were N-group bacteria, Proteus morganii, P. vulgaris, Hafnia alvei, Citrobacter spp., Vibrio spp., Aeromonas spp. etc. For the summer samples, P. morganii were found most frequently, followed by the N-group bacteria. On the other hand, for the winter samples, only the N-group bacteria were found, and other histamine-forming bacteria were not detected. The method of isolating the various histamine-forming bacteria was discussed.

赤身魚類の貯蔵中におけるヒスタミンの消長

Changes in histamine contents during storage at 5°C, 20°C and 35°C were examined in the ordinary and dark meats of sardine, saury pike, mackerel, yellowtail, skipjack, big-eye tuna and horse mackerel. During storage at 20°C histamine was produced and accumulated at the highest concentrations. In the meats of sardine, saury pike, mackerel and horse mackerel the amouts of histamine increased gradually during storage at 5°C. Histamine formation of dark meat was less than that of ordinary meat at the same storage temperature. During storge at 5°C or 20°C large amouts of histamine were detected sometimes in the fresh meats of sardine, saury pike and mackeerel whose volatile basic nitrogen contents were lower than 20mg/100g. The relation between histamine contents and numbers of histamine-forming bacteria was examined in the meat of mackerel during storage at 20°C. At the early stage of storage psychrophilic and halophilic histamine-philic and halophilic histamine-forming bacteria were predominant, i.e., after 2 days of storage when 107-108 of the bacteria were measured, 440mg/100g of histamine was produced. With the lapse of time mesophilic and non-halophilic histamine-forming bacteria incresed in numbers.

Changes in numbers of histamine-forming bacteria on/in common mackerel stored at various temperatures.

In the previous paper, the authors reported that histamine-forming bacteria found in the fish samples were N-group bacteria, Proteus morganii, P. vulgaris, Hafnia alvei, Citrobacter spp., Vibrio spp., Aeromonas spp. and so on. This study was carried out on the changes in the numbers of histamine-forming bacteria on/in common mackerel samples stored at different temperatrues. In both cases of the samples stored at 5°C and 10°C, main histamine formers were only N-group bacteria. In the samples stored at 15°C, the formation of histamine might be attributed to the N-group bacteria, although P. morganii increased during the storage. As for the samples stored at 20°C, a great part of histamine at the early stage of the storage might be accumulated by the N-group bacteria and at the later stage by P. morganii. In both cases of the samples stored at 25°C and 30°C, the accumulation of histamine was due to the action of P. morganii to a great extent.

フィッシュミールの原料に存在するヒスタミン生成菌

From 1978 to 1979, outbreaks of a disease in broiler chicks, chiefly manifested as gizzard erosion (GF), were observed in Japan. The GE was caused by feeding high level of fish meal, having some toxic substance formed from free histidine or histamine with protein in the fish meal at heating process. On the other hand, it was also observed that the stomachs of trouts were eroded by histamine in fish meal. It has been considered by the authors of trouts were eroded by histaming in fish meal. It has been considered by the authors that histamine in fish meals might be produced by histamine-forming bacteria during storage of their raw materials. The present study was undertaken to investigate the species of histamine-forming bacteria in the raw materials of fish meals. In the raw material (sardine, storage temperature 17°-20°C) collected from the fish meal factory S in July, the N-group bacteria (107-108) were predominant organisms and P. morganii (104-105), Citrobacter (104-105) and unidentified bacteria (104-105) were also found, while in the raw material (miscellaneous, 32°-34°C) collected from the factory K in the same month, P. morganii (107-108) and Citrobacter (107-108) were dominant organisms but the N-group bacteria could not be detected. In the raw materials collected from the factory S (mackerel, 18°-21°C) and the factory K (miscellaneous, 18°-21°C) in October, the N-group bacteria were more than 106, while the other histamine-former groups were less than 104.

A new type of histamine-forming bacteria - III. Seasonal variations in numbers of psychrophilic and halophilic histamine-forming bacteria (N-group bacteria) in seawater and on marine fishes.

In the previous papers, the authors repored that a new type of histamine-forming bacteria (tentatively named N-group bacteria) was isolated from a common a mackerel, and that this group of bacteria were also found in Pacific saury and sardine, and gew well at 2.5 storage of thee fish samples. The present study was undertaken to obtain more information as to seasonal variation in the mumber of N-group bacteria in seawater and on the fisher skins and intesines. N-group bacteria werre found most abundantly in the sewater during the late autumn and winter, and it is considered that this group of bacteria strikingly decreased in number when the water temperature rose above 22°C. The majouity of the fresh fish samples had less than 100 organisms of organisms of N-group bacteria per cm2 of skin; and especially in the summer samples, they were below 10 orgainisms. The number of this group of bacteria increased at 2.5storage of the fish samples and eached to 107-108 level in a few samples. This group of bacteria were found in all of the intesine amples, where their number ranged from 103 to 108 per gram. A selective enrichment medium with PH 4.5 was devised for detection and isolation of N-group bacteria.

A new type of histamine-forming bacteria - II. Occurrence of psychrophilic and halophilic histamine-forming bacteria (N-group bacteria) on/in red meat fish.

In a previous paper, the authors reported that psychrophilic and halophilic histamine-forming bacteria, which could produce histamine at 5°C, could be isolated from the common mackerel flesh homogenates stored at 5°C and 20°C, these organisms were named “ N-group bacteria ” for the time being. The present study was undertaken to obtain further information as to the occurrence of Ngroup bacteria on/in red meat fist, common mackerel, saury pike, and sardines. These fish samples were allowed to stand at 2.5°C. N-group bacteria occurred on/in all samples; the number of them in the fresh ones were 1 to 102 per gram of the flesh (0.01 to 1% of total bacterial number), while those in the spoiled ones were 106 to 108 (1 to 10%). N-group bacteria seem to occur as a part of the normal surface microflora of marine fish.

A pungent compound produced in the meat of frozen yellowfin tuna and marlin.

Abnormal meat with a pungent taste was detected in yellowfin tuna and white and black marlins, and food poisoning occurred by ingestion of these meats. In this study the pungent compound was identified and the cause of its production was investigated. In the abnormal meat, pH values were higher than 6.50 and histamine content was 308 to 543mg/100g. which is much higher than the amount which can cause food poisoning. The taste of the abnormal meat was just the same as that of histamine, which is known to be pungent. So the pungent compound in the abonormal meat was concluded to be none other than histamine. The values of volatile basic nitrogen and the viable counts of bacteria were low in the abnormal meat. Therefore, the abnormal meat was judged to be as fresh as the normal one. The viable counts of psychrophilic and mesophilic histamine-forming bacteria were also too low to produce a large amount of histamine. The activity of histidine decarboxylase was found to be higher in the abnormal meat than in the normal one. It is concluded that not histamine-forming bacteria but the high activity of histidine decarboxylase in the abnormal meat was responsible for the accumulation of histamine.

A new type of histamine-forming bacteria. Isolation of psychrophilic and halophilic histamine-forming bacteria from Scomber japonicus.

The present paper deals with the isolation and identification of a new type of histamine-forming bacteria. The homogenates of common mackerel flesh, stored at 5°Cand 20°C, contained large amounts of histamine. The bacterial isolates from these two homogenates were examined for their ability to produce histamine in mackerel infusion broth. The organisms of one group of the isolates, which could not be identified with any of the known genera, were capable of producing histamine at a temperature of 5°C. All of the group strains were Gram-negative coccobacilli and motile by one polar flagellum; they also fermentatively metabolized glucose to acid and gas. These strains grew at 5°Cbut not at 35°C; they grew well in a medium with 1 to 3 percent NaC1, but did not grow in the absence of NaC1. The authors have named the unidentified organisms “N-group bacteria”. This bacteria group may be important for the problem of food hygience, because it is a new type of histamine-forming becteria.