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No.25 (1978/12) >

 
Title :レサズリンテストを中心とする生乳の細菌学的検査 II(畜産学科)
Title alternative :Bacteriological examination of raw milk with particular reference to resazurin test II (Department of Animal Husbandry)
Authors :日越, 博信
久場, 良保
大城, 義正
Authors alternative :Higoshi, Hironobu
Kuba, Yoshiyasu
Oshiro, Yoshimasa
Issue Date :1-Dec-1978
Abstract :著者らは, 沖縄県における生乳の細菌による汚染状況を調査中であるが, 今回は, バルク酪農家とユニット酪農家とに分け, それらの工場生乳および酪農家で段階別に採取した生乳について, 調査を行なった。工場生乳のRTは, バルク酪農家の46試料すべてが2級以下であったが, ユニット酪農家の181試料では2級以下が27%であった。総菌数は, バルク酪農家の試料では91%が400万以下であったのに対し, ユニット酪農家の試料では80%が逆に400万以上であった。また生菌数は, 20℃および35℃培養では10^4∿10^8,5℃培養では10^2∿10^7,大腸菌群数では10^2∿10^6の範囲にあったが, バルク酪農家の試料はユニット酪農家のそれに比べて, いずれの細菌数も少なかった。なお, 細胞数は51万以上の試料が62%もあり, 特にこのような試料はバルク酪農家に多かった。一方, 酪農家で段階別に採取した試料のRTは, 乳房乳では1∿2級が, バケット乳, 冷却前乳および冷却乳では2∿3級が多かった。総菌数, 3種培養菌数および大腸菌群数は, 一般に後段階ほど増加したが, 各細菌数の増加率はバケット乳で最も高かった。また, 冷却乳の各細菌数は, 冷却前乳のそれに比べて増加したが, 増加率はバルク酪農家よりユニット酪農家の方で高かった。なお, RTの級と各細菌数との関係は, 級が高いほど細菌数も多かった。
Although the authors' survey of the status of bacterial contamination of raw milk in Okinawa, Japan, is still under way, an investigation has recently been made for contamination of the raw milk delivered to the processing plant by the dairy farms. and of the mammary milk, bucket milk, milk before cooling, and cooled milk at the farms, by classifying the farms into those using the bulk cooler and those using the unit cooler, and the following have been found : The resazurin test of raw milk delivered to the plant showed that 46 samples delivered by the farms using the bulk cooler were all classed as class 2 or below, while only 27% of 181 samples delivered by the farms using the unit cooler were classed as such. The direct microscopic count was not more than 4,000,000/ml in 91% of the samples delivered by the farms using the bulk cooler, while conversely 80% of the samples delivered by the farms using the unit cooler were found to contain not less than 4,000,000/ml. In all of these samples, the viable bacterial count was (10)^2∿(10)^7/ml by incubation at 5℃, and (10)^4∿(10)^8/ml by incubation at 20℃ and 35℃, and the coliform count, (10)^2∿(10)^6/ml, however, the number of either bacteria in the samples delivered by the farms using the bulk cooler was smaller than that in the samples delivered by the farms using the unit cooler. The resazurin test of the samples collected at the dairy farms showed that many samples of mammary milk were classed as 1 or 2 class, while many samples of bucket milk, milk before cooling and cooled milk were classed as 2 or 3 class. The direct microscopic count, the viable bacterial counts by the three different ways of incubation and the coliform count were greater at the later stages, however, the ratios of increase in the numbers of bacteria were greatest in the bucket milk. The ratio of increase in the number of bacteria in the cooled milk to that in the milk before cooling was higher in the samples from the farms using the unit cooler than in those from the farms using the bulk cooler. There was such a relationship between the classes by the resazurin test and the numbers of bacteria that the higher the class, the greater were the numbers of bacteria.
Type Local :紀要論文
ISSN :0370-4246
Publisher :琉球大学農学部
URI :http://hdl.handle.net/20.500.12000/4215
Citation :琉球大学農学部学術報告 = The Science Bulletin of the Faculty of Agriculture. University of the Ryukyus no.25 p.411 -420
Appears in Collections:No.25 (1978/12)

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