Dairy Ingredients for Food Processing

Principles of Cheese Technology 237

Table 10.3. Some characteristics of thermophilic strains used in cheese making.

Characteristic Streptococcus

thermophilus

Lactobacillus

delbrueckii ssp.

bulgaricus

Lactobacillus

delbrueckii ssp.

lactis

Lactobacillus

casei ssp. casei

Cell shape and

confi guration

Spherical to

ovoid, pairs

to long chains

Rods with round ends,

single/short chains,

metachromatic

granules

Rods, round ends,

metachromatic

granules

Rods with square

ends, short/

long chains

Catalase reaction – – – –

Growth temperature ( ° C)

Optimum 40 – 45 40 – 45 40 – 45 37

Minimum 20 22 22 15 – 20

Maximum 50 52 52 40 – 45

Incubation Temp. ( ° C) 40 – 45 42 40 – 45 37

Heat tolerance,

60 ° C/30 minutes

+ + + + −

Lactic acid isomers L( + ) D( − ) D( − ) L( + )

% Lactic acid

produced in milk

0.7 – 0.8 1.5 – 4.0 1.5 – 3.0 1.2 – 1.5

% Acetic acid

produced in milk

Trace Trace Trace +

Gas (CO 2 ) production – – – –

Proteolytic activity ± + + ±

Lipolytic activity ± ± ± ±

Citrate fermentation – – – –

Flavor/aroma

compounds

+ + + + + ±

Mucopoly - saccharide

production

± + + − ±

Hydrogen peroxide

production

± + + +

Alcohol production – Trace Trace Trace

Salt tolerance

(% maximum)

2.0 2.0 2.0 2.0

Adapted from Chandan and Shahani (1995)

duces CO 2 , which generates large holes in
the interior of cheese (eyes) in Swiss cheese
varieties when under pressure. Surface
smear - ripening organisms consisting of Bre-
vibacterium linens , microcooci, and certain
yeasts and molds produce distinct fl avors
and textures, while blue mold ( Penicillium
roqueforti/glaucum ) develops a blue - veined
appearance and characteristic fl avor. A white
mutant of Penicillium roqueforti is used in
Nuworld cheese production, imparting a typ-
ical blue cheese fl avor with white veins. Sim-
ilarly, white mold ( Penicillium caseicolum/
candidum, camembertii ) gives a snow - white
appearance and discreet fl avor profi le to
Camembert and Brie cheeses.

Accordingly, the bacteria and fungi

present in the starter leave an imprint on

cheese fl avor and texture. Other cultures,

added along with starter cultures, are used as

ripening adjuncts. They may be bacterial or

yeast cultures, or non - growing attenuated

cultures designed to furnish desirable

enzymes. For instance, certain lactobacilli

and pediococci are also used; they grow

during cheese ripening and deliver ripening

enzymes. Consequently, the basic character

and individuality of a cheese are governed by

the type, composition, growth, and metabolic

attributes of the starter. Besides the genus and

species of the organism, it is important to

remember that starters may contain various