Relation between Mesophilic and Psychrotrophic Aerobic Sporulating Microorganisms in Milk

作     者：Vladimir Foltys Katarina Kirchnerova 

作者机构：Animal Production Research Centre Nitra Hlohoveck6 2 Luzianky 95141 Slovak Republic 

出 版 物：《Journal of Agricultural Science and Technology(A)》 (农业科学与技术（A）)

年 卷 期：2012年第2卷第1期

页      面：97-103页

学科分类：0832[工学-食品科学与工程（可授工学、农学学位）] 083002[工学-环境工程] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 08[工学] 083203[工学-农产品加工及贮藏工程] 

主　　题：Milk spore-forming aerobic microorganisms mesophilic psychrotrophic 

摘      要：The occurrence and the detection system of mesophilic and psychrotrophic aerobic sporulating microorganisms （MPAS） in raw cow＇s milk were studied. Samples of raw cow＇s bulk tank milk were taken 21 times in 14 farms during one year. Basis of the method for MPAS assessment is the milk sample inactivation at the temperature 80-82 ℃ for 30 minutes followed by incubation in cultivation dishes at 30 -4- 1 ℃ for 3 days-mesophilic aerobic sporulates （MAS）, and at 6.5 .4- 1 ℃ for 10 days-psychrotrophic aerobic sporulates （PAS）. The total count of MPAS was within the span 2.5-340 CFU/mL （colony forming units）. Average plate count of MPAS was 59.4 CFU/mL with variation coefficient 93.1%. MPAS count found in the same dishes at incubation for mesophilic and subsequently strictly psychrophilic microorganisms （MAS ＋ SPAS） which enables to exclude overestimation of results by sporulates able to grow at both incubation temperatures was on average 56.9 CFU/mL what represents 95.8% out of the number of sums of individual dishes at two temperatures （MAS ＋ PAS）. Correlation coefficient of these two types of results r = 0.99 gives evidence of close dependence that is expressed by linear regression equation y = 0.9773x. We can consider the method using at first 30 .4- 1 ℃ and subsequently 6.5 -4-1℃ （MAS ＋ SPAS） as more correct than the method with the opposite order of cultivation temperatures because of better regression coefficient of linear dependence and higher correlation coefficient in relation to the sum of independent incubations （MAS ＋ PAS）.