著者
板屋 民子 飯島 正雄 斉藤 貢一 正木 宏幸 青木 敦子 斎藤 章暢 安藤 佳代子 徳丸 雅一 坂東 正明
出版者
Japanese Society of Food Microbiology
雑誌
食品と微生物 (ISSN:09108637)
巻号頁・発行日
vol.8, no.4, pp.203-212, 1992-03-20 (Released:2010-07-12)
参考文献数
10

A large number of Photobacterium phosphoreum (6-7 log/g) was isolated from “tamagoyaki” (a kind of nigirisushi; Japanese food) that had been lumineferous in the dark. The isolates were smeared on the surfaces of sliced “tamagoyakis”. After the incubation at 10°C for 48 hr or at 25°C for 24 hr, the surfaces became luminous. It was indicated that this abnormality of “tamagoyaki” was caused by contamination with and multiplication by P. phosphoreum.On the surface of “tamagoyaki”, the bacteria in an early growth phase in such a small number as 4 log/g luminesced. Furthermore, the luminescence was observed when pieces of squid, boiled prawn or “yakichikuwa” (a kind of food made of fishes) with the bacteria were incubated, but not observed on pickled Japanese gizzard shad. Nevertheless the the bacteria grew on the surface of tuna, but no luminescence was observed on it.The bacteria produced a small amount of histamine on squid and tuna (less than 250μg/g), and their ability to putrefy food seemed to be low.The opitmum concentration of sodium chloride for growth of the bacteria in a medium was 3%, but they grew in food containing sodium chloride less than 0.5%. When sodium chloride in the medium was replaced by potassium chloride, calcium chloride, magnesium chloride, ammonium chloride or sodium phosphate, the bacteria were still able to grow but unable to grow when replaced by potassium phosphate or sucrose. The bacteria metabolized arginine by arginine decarboxylase but not by arginine dehydrolase.
著者
斎藤 章暢 徳丸 雅一 青木 敦子 安藤 佳代子 正木 宏幸 板屋 民子 丸山 務
出版者
日本食品微生物学会
雑誌
日本食品微生物学会雑誌 (ISSN:13408267)
巻号頁・発行日
vol.11, no.1, pp.29-33, 1994

<I>Listeria monocytogenes</I> (<I>L. m</I>. ) in shredded cheese was examined for its growth behavior during cold storage and cooking. During storage at 5°C, the concentration after inoculation decreased up to day 20 and thereafter increased. On day 77, the concentration was recovered to almost the same level as that at the time of inoculation, in shredded cheese inoculated with 10<SUP>4</SUP> or 10<SUP>6</SUP>/g <I>L.m</I>. and increased by 1-2 orders in shredded cheese inoculated with 10<SUP>1</SUP>/g <I>L .m</I>. . Also during storage at 10°, the inoculated <I>L.m</I>. decreased up to day 20 and thereafter increased, each bacterial concentration increased by 1-4 orders. Organoleptically, fungigenesis occurred from days 20 and 15 at 5° and 10°, respectively. The number of bacteria surviving in the pizza inoculated with 10<SUP>6</SUP>/g <I>L.m</I>. was 3.6-23/100 g after heating at 200°C for 5 min, while heating at 250°C for 5 min caused the death of all the inoculated bacteria, that is 10<SUP>6</SUP>/g. The change of the temperature at the center of the pizza while cooking tended to decrease with the increases in the temperature of storage and in the volume of ingredients, and these changes were also macroscopically recognizable.<BR>The above findings suggested that <I>L. m</I>. in shredded cheese dose not proliferate during the allowable period of storage before consumption and becomes extinct with general methods of cooking.