Influence of growth temperature on inactivation and injury of Escherichia coli O157:H7 by heat, acid, and freezing.
Influence of growth temperature on inactivation and injury of Escherichia coli O157:H7 by heat, acid, and freezing.
复制标题
生长温度对热、酸和冷冻灭活和损伤大肠杆菌 O157:H7 的影响。
DOI：
10.4315/0362-028x-61.4.395
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发表时间：
1998
影响因子：
2
通讯作者：
D. Golden
中科院分区：
文献类型：
--
作者：
Jeffrey J. Semanchek;D. Golden
研究了生长温度对0.1%蛋白胨水中大肠杆菌O157:H7热、乳酸和冷冻灭活和损伤的影响。分别从意大利腊肠、苹果酒和碎牛肉中分离得到3株大肠杆菌O157:H7。与37℃相比，10℃条件下菌株生长对加热获得的D值（DH值）和酸暴露（DA值）的降低（P < 0.01）有显著影响，但乳酸溶液中储存的苹果酒菌株除外。在10℃和37℃培养，54℃和56℃加热时，腊肠菌DH值最高（P < 0.01） （5.9 ~ 59.7 min）。在10℃条件下，52℃、54℃和56℃（分别为11.2、4.1和2.5 min）下的DH值最低（P < 0.01）。在10℃条件下生长的腊肠菌株在所有乳酸浓度下DA值最高（P < 0.01）。在37℃条件下，0.1和0.25%乳酸条件下，腊肠菌株的DA值最高（P < 0.01），而0.5%乳酸条件下，腊肠菌株与牛肉菌株的DA值无显著差异（P < 0.05）。在含2% NaCl的色氨酸大豆琼脂上，部分菌群受到高温和乳酸的亚致死伤害，无法形成菌落。在10℃条件下培养的菌株比在37℃条件下培养的菌株更容易受到亚致死热损伤。在-20℃条件下保存7个月，活菌数量降低4 ~ 6 log CFU/ml，但亚致死损伤很小。在-20℃条件下培养5个月后，10℃条件下培养的菌株对冷冻失活的敏感性高于37℃条件下培养的菌株。在10℃条件下培养和37℃条件下培养7个月时，苹果酒菌株的DF值高于牛肉和腊肠菌株（P < 0.01）。
The influence of growth temperature on heat-, lactic acid-, and freeze-induced inactivation and injury of Escherichia coli O157:H7 in 0.1% peptone water was investigated. Three strains of E. coli O157:H7 isolated respectively from salami, apple cider, and ground beef were evaluated. Growth of strains at 10 degrees C compared with growth at 37 degrees C had a significant impact on reducing (P < 0.01) D values obtained for heating (DH value), acid exposure (DA value), with the exception of the cider strain stored in lactic acid solutions. When strains were cultivated at 10 and 37 degrees C and heated at 54 and 56 degrees C, the salami strain possessed the highest (P < 0.01) DH values (5.9 to 59.7 min). When grown at 10 degrees C, the beef strain had the lowest (P < 0.01) DH values after heating at 52, 54, and 56 degrees C (11.2, 4.1 and 2.5 min, respectively). The salami strain grown at 10 degrees C had the highest (P < 0.01) DA values in all concentrations of lactic acid. When grown at 37 degrees C, the salami strain had the highest (P < 0.01) DA values after storage in 0.1 and 0.25% lactic acid, while DA values for the salami and beef strains did not differ (P > 0.05) when stored in 0.5% lactic acid. Portions of strain populations were sublethally injured by heat and lactic acid treatments, as evidenced by the inability of injured organisms to form colonies on tryptone soy agar containing 2% NaCl. Strains cultured at 10 degrees C were more susceptible to sublethal heat injury than the strains cultured at 37 degrees C. Storage of test strains at -20 degrees C for 7 months resulted in a 4- to 6-log CFU/ml reduction in viable population, but induced only minimal sublethal injury. After 5 months at -20 degrees C, strains cultured at 10 degrees C were more sensitive to freeze inactivation than strains cultured at 37 degrees C. When grown at 10 and cultured at 37 degrees C. When grown at 10 and 37 degrees C and stored at -20 degrees C for 7 months, the cider strain possessed higher (P < 0.01) DF values than the beef and salami strains.