Concentrated Fluid Milk Ingredients 133Somatic cell count : Individual producer
milk not to exceed 750,000 per mL.
SCM must meet strict microbiological
standards as follows:- Standard plate count (SPC): less than
1,000/g - Coliform: less than 10/g
- Yeast: less than 5/g
- Mold: less than 5/g
The recommended microbiological testing
methods for SPC, coliform, yeast and molds,
and thermoduric and thermophilic counts are
described in the Standard Methods for the
Examination of Dairy Products (APHA,
1992 ).Other Tests
There are several methods for assessing the
quality of evaporated milks and other con-
centrated milks. Some of the more frequently
used methods are described below. For a
detailed description of the methods as well as
other methods, see Methods for Quality
Assessment of UHT Milks (New Zealand
Dairy Research Institute, 1997 ).Gelation
Gelation may be detected by visual inspec-
tion and is often rare within 6 months of
production. Gelation may be indicated by
wheying - off and shrinkage of the gel away
from the wall of the container, failure of the
surface to fl ow when the container is tipped,
or the presence of curdy lumps when the
sample is disturbed.Fat Separation
Fat separation is evidenced by a cream layer
on top of the product. Fat separation can
be assessed by visual subjective, gravimet-
ric (weight test), or fat emulsifi cation
methods. When the visual method is used, aNFDM that are manufactured from skim
milk that has been respectively preheated to
82 ° C for 3 minutes or 82 ° C for 30 minutes
before evaporation and drying. Low - heat
NFDM is more suitable for nonsterilized
products such as sweetened condensed milk.
After reconstitution of the dried milk in water
and recombination with milk fat or vegetable
fat by high shear mixing and homogeniza-
tion, the processing steps similar to those
described above for evaporated milk and
sweetened condensed milk are followed.
Quality Assessment
The quality of concentrated milks depends on
the quality of the starting raw milk, other
ingredients added, and processing conditions
including adherence to strict sanitation and
good manufacturing practices. In the United
States, raw milk quality must follow Grade
A standards specifi ed by the PMO (FDA,
2003 ) as follows:
Temperature : Cooled to 10 ° C (50 ° F) or
less within four (4) hours or less, of the com-
mencement of the fi rst milking, and to 7 ° C
(45 ° F) or less within two (2) hours after the
completion of milking. Provided, that the
blend temperature after the fi rst milking and
subsequent milkings does not exceed 10 ° C
(50 ° F).
Bacterial limits : Individual producer
milk not to exceed 100,000 cfu/mL prior to
commingling with other producer milk. Not
to exceed 300,000 cfu/mL as commingled
milk prior to pasteurization.
Drugs : No positive results on drug residue
detection methods
Table 5.4. Heat classifi cation of nonfat dry milk.
Class Whey protein nitrogen (mg/g)
Low heat Not less than 6
Medium heat 1.51 – 5.99
High heat Not more than 1.5ADPI ( 2002 )