1 What is Quality Milk
Every merchant offering a product to a consumer will
use the term
''quality'' in discussing the merits of his product.
All too frequently
use of the term will not be qualified - the consumer
is never informed
as to what ''quality'' means. Is the product quality
good, poor or
indifferent? Thus, it must be made clear that the only
''quality''
acceptable in goat milk is the best possible, that is
Grade A. The
following are the important characteristics which
apply to ''Grade A''
quality goat milk.
2 The most important requirement to be met is that the
product must
be safe to drink - it must be free of pathogenic
bacteria, as well as
all forms of antibiotic, insecticide and/or herbicide
compounds.
Second in importance is good flavor which may
realistically be
characterized as the absence of any objectionable
flavor. Third in
importance is relative freedom from spoilage bacteria
and somatic or
body cells. Complete absence of such is usually not
possible, but all
cities and/or states do have laws which limit the
maximum numbers
permitted. The last major factor related to quality is
composition -
the amount of fat and other solids contained. There
are legal
restrictions pertaining to milk components which must
be adhered to.
While other factors enter into the quality of fluid
milk, the four
listed are of greatest importance.
3 Legal Aspects
Each producer must be acquainted with the requirements
of the
governmental agency under whose authority he or she
operates.
Regulatory agencies generally operate on the basis
that milk is milk,
whether obtained from a cow or a goat. Thus, the goat
milk producers
are expected to meet the same requirements as the cow
dairy.
4 Safe Milk
What must a goat keeper do to be certain the milk
produced is safe
for consumption -- that is free of disease producing
bacteria as well
as chemicals that might produce human illness? There
is no such thing
as absolute safety in milk, but experience has shown
that adoption of
certain practices has produced a satisfactory level of
safety. Without
a doubt, pasteurization is the most important practice
followed as a
means of assuring the safety of milk. When properly
done, and if
accompanied by the use of sterile containers and
effective protection
from recontamination, pasteurization does result in
milk free of
pathogenic organism. Pasteurization does not decrease
the risk from
contaminants such as anti biotics or other undesirable
chemicals. Those
materials must be kept out of milk; proper management
practices must be
followed to prevent such contamination.
5 Effective herd management has many aspects but the
production of
milk free of any contaminating bacteria is of major
importance.
Undesirable organisms may get into milk either through
the body of the
animal or from some external source after the milk has
been drawn.
Animals which are ill with or carriers of infectious
diseases may
transmit those pathogenic bacteria in their milk; most
states require
the producers to show that milk producing animals are
free of TB and
Brucellosis. Several organisms causing mastitis also
are pathogenic to
man. Regular tests and frequent inspections of milking
animals
coordinated with a definite plan for withholding the
milk from suspect
animals until confirmation tests can be completed are
a must.
6 The most frequent source of antibiotics in milk is
from improper
use of such agents in treating animals. Less
frequently milk may be
contaminated by the animals consuming feeds carrying
some form of
herbicide or insecticide, or by improper usage of such
materials around
the premises. Extreme caution must be practiced in the
use of such
materials -- follow directions for use very carefully.
Detection of
these contaminants in milk probably will require
testing by a branch of
the Health or Agriculture departments of the state.
7 Environmental contamination of milk as it is drawn
or subsequent to
milking is quite common; its prevention or
minimization requires
strictest attention to cleanliness and sanitation in
all phases of the
process. Several common sources of contaminants are:
1. Animals teats, udder, flank, etc.
2. Air carrying bacteria and/or particles of dust,
feed, manure, etc.
3. Insects
4. Improperly cleansed and sterilized utensils
5. People -- especially those handling the milk.
8 Contamination from these sources usually is in the
form of hair,
insect parts, particles of dust, feed, or manure or
bacteria
associated with these contaminants plus those
contributed by unclean
utensils. Practices required to minimize such
contamination include:
1. Milking animals in a specially provided, clean,
well ventilated
area separated from housing and/or feeding areas and
from the milk
handling and storage area.
2. Milking animals only after they have been properly
prepared.
a. Clip long hair from udder and flanks.
b. Wash udder to remove foreign material.
c. Wipe udder and teats with paper towel and a mild
bactericidal solution to help prevent mastitis and
stimulate
milk let-down. Thoroughly dry the udder. Dip teats
following milking in an approved teat dip solution.
3. Use properly designed and effectively cleansed and
sterilized
milk handling equipment, including reusable
containers.
4. Handle milk in milk handling and storage room only.
5. Cool milk to 40F or less within 2 hours of milking.
6. No person ill with a communicable disease, or a
carrier of such,
shall work in any capacity associated with the
production,
handling, storage, or transportation of milk.
9 Milk Flavor
The ideal flavor of milk is slightly sweet and/or very
slightly
salty with complete absence of strong characterizing
odors or flavors.
Milk produced by a clean, healthy, properly managed
goat herd usually
will be as described. But off flavors may develop in
milk from several
sources. Probably the most troublesome flavor found
occasionally in
goat milk is rancid or ''goaty.'' This is a strong,
musky flavor
having the same characteristics as the odor given off
by the buck
during mating season. While this flavor is sought in
milk used for
making certain varieties of cheese in several
countries, it has no
place in the American fluid milk market. If the rancid
goat flavor is
present in milk at the time of milking it will be
necessary to closely
check each individual doe in the herd to identify
those responsible.
They should be removed from the milking herd and
disposed of since
evidence indicates that this is an inherited trait and
probably will be
passed on to progeny.
10 Another common off-flavor which may be found in
milk as it is drawn
is oxidized. Both forms of rancidity, oxidized and
goaty, may develop
in milk after it is drawn. These may be less common in
goat's milk
than in cows, but may be found, especially as the doe
nears the end of
her lactation. Oxidized is a cardboard-like flavor
caused by
nutritional imbalances or by exposure to light
sources; rancid
''goaty'' flavor develops when the fat is partially
disintegrated by
enzyme action -- both are best controlled by
immediately heating the
milk to pasteurization temperature and protecting the
milk from
sunlight and ultra-violet light. When the milking
animals consume
certain strong-flavored plants, such as wild onion or
garlic, ragweed,
etc., their milk may have objectional flavor. If these
cannot be
eliminated from the feed, the flavor defect can be
minimized by
withholding such feed from the animals 3 to 4 hours
prior to milking.
11 Great care should be taken to prevent milk from
absorbing
off-flavors and odors from the atmosphere -- exposure
to strong food,
medicine, or chemical materials can quickly impart
those flavors to
milk. Atmospheric exposure should also be prevented
insofar as possible
to limit bacterial contamination. Handling milk with
utensils which
have not been properly cleaned and sterilized will
also cause bacterial
contamination which is most undesirable. Flavors such
as high acid,
yeasty, malty, or fermented/fruity can result from
growth of
contaminating microorganisms.
12 The growth of microorganisms in milk causes
disintegration of fat,
protein, and/or lactose and will soon make the product
unsuitable for
drinking. (There is an exception to this: the
production of cultured
dairy foods in which specific kinds of microorganisms
are added and
grown under closely controlled conditions). While
elimination of
bacterial contamination is an important factor in the
production of
good flavored, high quality milk, two other procedures
can be used to
protect and maintain good flavor and quality. The
first of these is
prompt cooling to near or below 40F with maintenance
of that low
temperature for the usable life of the milk (unless
heat processing is
involved in the manufacture of a product from the
milk). The second is
pasteurization to inactivate microorganisms and
enzymes, followed by
cooling and holding at low temperature. Such heat
treatments may vary
from basic pasteurization to ultra high temperature
processing with
temperatures of 145F to 191F. Examples of various heat
treatments which
legally constitute proper pasteurization are: 145F
(63C) for 30 min,
161F (72C) for 15 sec, 191F (89C) for 1 sec.
Processing at 280 to 300F
(138-149C) for very short times, when accompanied by
proper
protective packaging, can result in a product with
greatly extended
shelf life even without refrigeration. Most states
require that all
milk offered for sale must have been pasteurized and
packaged in
approved containers. A few states permit the sale of
raw milk under
restricted conditions. In all cases, the milk must
meet specified
bacterial limitations.
13 Somatic Cell Content
Somatic cells in milk are an indicator of the state of
health of
the udder and affect the quality of milk produced. The
term refers to
all forms of body cells of tissue or blood origin
which are passed into
milk through the mammary system. The cell count of
goat milk is
believed to be generally higher than that of cow milk;
the milk from
animals which have or have had mastitis usually has
substantially
higher cell content than that from completely healthy
udders. Some
stressors on the animal may cause elevated cell counts
in milk. Many
states have a legal limit ranging from 1 to 1.5
million cells per ml
in milk. Beyond that level the milk is termed
abnormal. Cell count
determinations can be made by a number of simple tests
such as the
Wisconsin Mastitis Test and California Mastitis Test,
both of which can
be conducted in the home. A direct microscopic count
may be made in a
laboratory. Some states offer a somatic cell count via
the DHIA testing
program.
14 Milk Composition
A discussion of the requirements for high quality milk
must
consider the composition of the product. Composition
refers to the
milk's content of major nutrients -- fat, protein,
lactose, and
minerals. Official assays for these chemical
components must be made by
accredited laboratories. Probably more controversy
arises over the
matter of composition of milk than any subject covered
here. When
offered for sale, to be legal, all milk must meet
specific requirements
as to composition. Those legal limitations may vary
slightly from state
to state, but most are based on the 1978 version of
the ''Grade A
Pasteurized Milk Ordinance'' published by Public
Health Service, Food
and Drug Administration which the regulatory agency
has adopted. Milk
is defined therein as containing a minimum of 3.25milk
fat and 8.25
milk solids-not-fat (MSNF) which is the sum of the
protein, lactose,
and minerals. Lowfat milk may contain 1/2, 1, 1-1/2,
or 2 percent milk
fat, and skim milk is that which contains less than
1/2 percent milk
fat; all must contain a minimum of 8.25MSNF.
Additional MSNF may be
incorporated into the product during processing. Any
milk product which
differs from the 3.25milk fat, 8.25MSNF (either less
fat or more
MSNF) must show its proper name and the amount of fat,
protein, and
sugar (lactose), plus several other nutrients, in a
normal serving (8
fl oz) on the label of the package.
15 These legal limitations pose some problems to the
goat milk
producer and/or processor. Because most of the animals
still follow
natural breeding habits, at any given time, most of
the milking does
are in approximately the same stage of lactation.
This, plus the fact
that the season of the year influences milk
composition, results in
fairly large shifts in fat and MSNF content of the
goat milk available
throughout the year. Experience has shown that the
milk from a single
doe or a very small flock of goats may vary from a low
of 2 22568349762258
MSNF during mid-summer when temperatures are high and
when the does are
in mid-lactation to a high of 5
225683497622587700000000000000000000000000
animals are completing their lactation. Consumers do
not care to
purchase a product exhibiting such variance in
composition; and a
considerable amount of milk produced during
mid-lactation in summer
months does not meet legal standards. The cow dairy
industry has the
same problem; but of lesser magnitude because, at any
given time, the
animals in a normal herd are in all stages of
lactation. They also have
available commercial sources of Grade A cream and
nonfat dry milk
which can be used to standardize fat and MSNF content
of their fluid
products. With the continued growth of the goat dairy
industry these
same developments will become available. The problem
is to provide
products of uniform composition now -- while herds are
small and
concentrated sources of Grade A fat and MSNF are not
available.
16 To change the seasonal fluctuation it will be
necessary to improve
methods of light control and/or hormonal control
combined with
artificial insemination so as to have times of
parturition occurring
throughout all months of the year. Concentrated
sources of Grade A fat
and MSNF will somehow become available when there is
sufficient demand
to make those products economically feasible.
