Guarding against disease
Milk, a natural liquid food, is one of our most nutritionally complete foods, adding
high-quality protein, fat, milk sugar, essential minerals, and vitamins to our diet.
However, milk contains bacteria that––when improperly handled––may create
conditions where bacteria can multiply.
Most of the bacteria in fresh milk from a
healthy animal are either harmless or beneficial.
But, rapid changes in the health of an
animal, or the milk handler, or contaminants from polluted water, dirt, manure,
vermin, air, cuts, and wounds can make raw milk potentially dangerous.
How do microorganisms enter the milk supply?
Our environment contains an abundance of microorganisms that find their way to the
hair, udder, and teats of dairy cows and can move up the teat canal.
Some of these
germs cause an inflammatory disease of the udder known as mastitis while others
enter the milk without causing any disease symptoms in the animal.
organisms can enter the milk supply during the milking process when equipment used
in milking, transporting, and storing the raw milk is not properly cleaned and sanitized.
All milk and milk products have the potential to transmit pathogenic (disease- causing)
organisms to humans.
The nutritional components that make milk and milk products
an important part of the human diet also support the growth of the organisms.
Drinking raw milk causes foodborne illness, and dairy producers selling or giving raw
milk to friends and relatives are putting them at risk.
What are common pathogens in milk?
Illnesses from contaminated milk and milk products have occurred worldwide since
cows have been milked.
In the 1900s it was discovered that milk can transmit
tuberculosis, brucellosis, diphtheria, scarlet fever, and Q-fever (a mild disease
characterized by high fever, chills, and muscular pains) to humans.
threat of these diseases and the incidence of outbreaks involving milk and milk
products has been greatly reduced over the decades due to improved sanitary milk
production practices and pasteurization.
Salmonellosis is the most common disease transmitted in raw milk.
This organism is shed in the feces of cattle and picked up on the animals’ hair or
Many strains of
can cause foodborne illness in humans, and all
strains exhibit the same symptoms such as gastroenteritis (vomiting and diarrhea).
Pasteurization destroys the
organism, and although pasteurized milk,