Table 1. Populations in the dried powders and respective survival levels. Data are of Streptococcus thermophilus Y-12S grown on trehalose.

Drying process

Protective solution

Populations in humid beads (CFU/g)

Population (CFU/g powder)

Survival to initial drying (%)

After initial drying

After aw stabilization

CAD1

Peptone

2.5 x 108

7.0 x 107

4.5 x 106

0.7

Lactose

2.6 x 108

4.5 x 108

2.9 x 108

24

Trehalose

1.5 x 108

4.3 x 108

1.4 x 108

37

Whey-sucrose

1.2 x 108

6.1 x 108

8.2 x 107

98

FD2

Peptone

2.5 x 108

6.6 x 107

2.8 x 106

0.6

Lactose

2.6 x 108

4.0 x 108

2.1 x 108

17

Trehalose

1.5 x 108

4.5 x 108

4.2 x 108

31

Whey-sucrose

1.2 x 108

3.4 x 108

2.4 x 108

50


1 CAD = convection air drying
2 FD = freeze-drying

Supported by UNESCO / MIRCEN network