Dairy Ingredients for Food Processing

Dairy Ingredients for Food Processing: An Overview 9

may indicate the presence of chemicals in
the milk. A recommended standard is 0.13%
to 0.17% TA.
Temperature According to the PMO
standard, the temperature of milk must never
exceed 7 ° C (45 ° F). A recommended standard
is 5 ° C (40 ° F) or less.
Flavor is an important indicator of quality,
as stated earlier. The milk should be fresh and
clean with a creamy appearance. Elevated
bacteria counts can produce off - fl avors (for
example, acid, bitter). Feed fl avors may vary
from sweet to bitter and indicate the last
items in a cow ’ s diet, such as poor feed,
weeds, onion, or silage. Elevated somatic cell
counts make milk taste salty and watery.
Water in the milk gives it a watery taste.
Dirty, “ barny, ” and “ cowy ” fl avors occur
from sanitation conditions and air quality at
the dairy farm. Oxidized or rancid fl avors
occur from equipment operation and
handling.
There are no federal standards for fl avor.
All receiving plants should fl avor milk for
defects before accepting it.
A recommended standard is that no off -
fl avor exists.
Appearance is not a measured criterion
but for indications of quality it is as important
as fl avor. There are no federal standards for
appearance. Most receiving plants must note
any color or debris defect in the milk before
accepting it. A recommended standard is
“ White, clean, no debris, and fi lter screen of
2 or less (sediment test). ”
Antibiotics and other drugs may not be
present in milk. All raw milk must conform
to the PMO Grade A regulations (Frye, 2006 ).
To be considered organic, no milk can be
used from a cow that has been treated with
antibiotics without a 12 - month holding
period following treatment. For conventional
milk, a treated cow will be withheld from the
milking herd for about 5 days.
Added water is an adulteration. Testing
the freezing point of milk using a cyroscope
indicates if abnormal amounts of water exist

in the load. In most states it is illegal to have

a freezing point above − 0.530 ° Hortvet scale.

A recommended standard should be − 0.530 °

Hortvet or less.

Sediment is measured by drawing 1 pint

of sample through a cotton disk and assign-

ing a grade of 1 (good) to 4 (bad) to the fi lter.

A grade of 1 or 2 is acceptable. A processor

also may monitor for sediment by screening

the entire load through a 3 - inch mesh fi lter at

the receiving line. There are no federal stan-

dards. Most receiving plants should require a

fi lter grade of 1 or 2, although a 3 may be

accepted.

A recommended standard is “ No exces-

sive material in a 3 - inch sani - guide fi lter. ”

Fat and milk - solids - not - fat (MSNF)

have FDA standards of identity for milk of

3.25% fat and 8.25% MSNF. This is the rec-

ommended standard.

In the recent past, major advances in dairy

processing have resulted in improvement in

safety and quality of products. In particular,

ultra - pasteurization techniques and aseptic

packaging systems have presented the indus-

trial user with extended and long shelf - life

products.

Basic Steps in Milk Processing

It is benefi cial for food developers and pro-

cessors to know the basic steps involved in

dairy processing. A detailed description of

basic dairy processing is given in Chapter 4.

Milk production, transportation, and process-

ing are regulated by Grade A Pasteurized

Milk Ordinance (USDHHS PMO, 2003 ; Frye

and Kilara, 2006 ). Chapter 15 of this book

deals with the regulatory aspects of dairy -

based ingredients. Figure 1.3 shows the

journey of milk from the farm to supermar-

ket, including processing at the milk plant.

Bulk Milk Handling and Storage

The handling and storage of bulk milk are

key components of good quality milk. Dairy