Glycerol Enhances the Antifungal Activity of Dairy Propionibacteria
Table 2
Results from analysis of cultured broth after 72 h of incubation with 5 different type strains of propionibacteria. Results include bacterial counts, pH, glycerol, acids, and inhibition against three different spoilage fungi in a microtitre plate assay. Data in the table show mean values with one standard deviation ().
Bacteria
Broth
Bacterial count cfu/ml (log)
pH
Glycerol and acids (mM)
Supernatant inhibition*
Glycerol
Lactic acid
Acetic acid
Propionic acid
Rhodotorula mucilaginosa
Penicillium commune
Penicillium roqueforti
P. acidipropionici
SL
8.6 ± 0.1
5.7 ± 0.0
0
65 ± 3
22 ± 1
50 ± 2
−
−
−
GLY
8.5 ± 0.4
4.3 ± 0.0
54 ± 1
0
0
46 ± 0
+
+
+
P. freudenreichii subsp. shermanii
SL
9.7 ± 0.1
6.0 ± 0.0
0
<10
39 ± 2
77 ± 1
−
−
−
GLY
9.4 ± 0.1
4.7 ± 0.0
73 ± 1
0
0
26 ± 0
+
−
−
P. freudenreichii
SL
9.5 ± 0.1
5.9 ± 0.0
0
<10
39 ± 1
75 ± 0
−
−
−
subsp. freudenrechii
GLY
8.8 ± 0.0
4.7 ± 0.0
74 ± 1
0
0
26 ± 2
+
−
−
P. thoenii
SL
9.2 ± 0.1
5.9 ± 0.0
0
93 ± 4
17 ± 1
35 ± 2
−
−
−
GLY
9.1 ± 0.1
4.5 ± 0.0
69 ± 1
0
0
33 ± 1
+
+
+/−
P. jensenii
SL
9.5 ± 0.2
5.8 ± 0.0
0
<10
43 ± 1
89 ± 1
−
−
−
GLY
9.2 ± 0.1
4.3 ± 0.0
51 ± 1
0
0
49 ± 1
+
+
+
*Inhibition was interpreted a: – (no inhibition compared to the control), +/− (weaker fungal growth than control) or + (complete inhibition).
