Dairy Ingredients for Food Processing

Principles of Cheese Technology 251

tant to meet regulatory requirements. As the

FDM increases, the MNSF tends to increase.

The FDM of cheese is controlled by the

casein:fat ratio in milk.

Acidity/pH

Acidity/pH control is critical at the time of

cutting, draining, and milling, as well as after

one day and seven days of ripening (Hill,

2009 ). During the fi rst week of ripening, the

pH of most cheese varieties should be 5.0 to

5.1. Normally, the pH should increase at the

end of the ripening period. The surface of

mold - ripened cheeses registers an increase

from pH 4.6 to pH 7.0. This increase is

ascribed to formation of alkaline fragments

of casein. The increase in pH enhances the

activity of proteases and lipases.

Ripening Temperature

For a given cheese, the temperature of ripen-

ing is also a factor of cheese quality. For

cheddar, it is recommended to ripen the

blocks at 4 ° C to 10 ° C (39 ° F to 50 ° F) for the

fi rst few weeks, followed by ripening at 8 ° C

to 10 ° C (46 ° F to 50 ° F). A low temperature

slows down the starter as well as non - starter

organisms to control pH within the desirable

range (above 5.0) and to reduce formation of

off fl avors. Other varieties are ripened at

10 ° C to 15 ° C (50 ° F to 59 ° F), whereas

surface - ripened cheeses are ripened at 11 ° C

to 15 ° C (52 ° F to 59 ° F).

Humidity Control

Some cheeses, especially the surface - ripened

varieties, require high humidity and air cir-

culation to encourage the growth of molds

and yeasts. The humidity requirement for

surface - bacterial - ripened cheeses is 90% to

95%, whereas fungal - ripened cheeses need

85% to 90%. Cheese with a dry rind needs

80% to 85% humidity.

impart off fl avors to the cheese. The water
activity generally increases with ripening.
The percent moisture in nonfat solids of
cheese (MNFS) is considered a better param-
eter to explain ripening patterns. It is calcu-
lated as follows:

MNFS

cheese moisture

cheese fat)

=

( )

−

×

%

(% 100

100

In New Zealand, high - quality cheddar
cheese is targeted to have a MNFS percent-
age in the range of 50% to 57%. At 10 ° C
(50 ° F), the MNFS is observed to decrease
from 56% after three to four months of ripen-
ing to 53% at six to seven months of ripening.
Critical parameters for control of MNFS
include pH (at the whey draining and salting
stages) and cooking temperature and fat in
dry matter.

Salt Concentration

A better parameter for quality control is salt
in moisture (S/M) content of cheese. It is
calculated as:

%

%

%

S/M

salt in cheese

moisture in cheese

=

( )

( )

× (^100)
High S/M controls the acidity develop-
ment by starter bacteria; low pH discourages
the growth of undesirable bacteria and infl u-
ences proteolysis and generation of fl avor
compounds. The target level of the S/M per-
centage is 2.5% to 6% for cheddar cheese.
Fat Content
Fat content makes cheese soft. When the fat
content is high, whey drainage is impaired.
Fat in dry matter (FDM) is considered a
better quality control parameter. It is calcu-
lated as follows:
%

%

%

FDM

fat in cheese

total solids in cheese

=

( )

( )

× (^100)
For cheddar cheese, the target value is
50% to 56% FDM. This value also is impor-