PMC

The mean of species per sampling farm on different sampling dates was calculated for every bacterial class. Three bacterial classes showed dominance in different seasons of the year: Gammaproteobacteria in spring and winter (April-May and January), Bacilli in summer (August), and Actinobacteria in autumn (November).

Psychrotrophic (□) and mesophilic (▴) bacterial population dynamics in raw milk sampled between April 2004 and January 2005. Each sampling date represents an average of samples from four farms (mean + the standard error).

Percentage of isolates showing lipolytic, proteolytic, or both enzymatic activities in different genera. The number of isolates in each genera (n) is also indicated: Brevundimonas (n = 6), Delftia (n = 5), Pseudomonas (n = 33), Acinetobacter (n = 29), Enterococcus (n = 11), Leuconostoc (n = 18), Streptococcus (n = 10), Lactococcus (n = 22), Microbacterium (n = 43), Rhodococcus (n = 10), Chryseobacterium (n = 14), and Sphingobacterium (n = 6). For more details, see Fig. and and Tables S1 to S7 in the supplemental material.

Phylogenetic tree of isolates belonging to the Sphingobacteria class. The tree shows the relationship based on partial sequences of the 16S rRNA gene of selected isolates. No special marks on the isolate name indicates no enzymatic activity, gray background indicates lipolytic activity; isolates with names underlined represent new species. The letters F and H in isolate names are the different farms from which the bacteria were obtained. The sequence alignment was performed by means of the CLUSTAL W program, and the tree was generated by the neighbor-joining method with Kimura two-parameter distances in MEGA 3 software. Bootstrap values (from 1,000 replicates) greater than 50% are shown at the branch points. The bar indicates 2% sequence divergence.

Phylogenetic tree of isolates belonging to the genus Pseudomonas. The tree shows the relationship based on partial sequences of the 16S rRNA gene of selected isolates. No special marks on the isolate name indicates no enzymatic activity; gray background indicates lipolytic activity; black background with white letters indicates proteolytic activity; diagonal gray lines in the background of the isolate's name indicates both lipolytic and proteolytic activity; isolates with names underlined represent new species. The letters D, F, and G in isolate names are the different farms from which the bacteria were obtained. The sequence alignment was performed by means of the CLUSTAL W program, and the tree was generated by the neighbor-joining method with Kimura two-parameter distances in MEGA 3 software. Bootstrap values (from 1,000 replicates) greater than 50% are shown at the branch points. The bar indicates 1% sequence divergence.