Cattle - Raising Small Animals - page 483

Dairy Processing
When you produce milk, you can drink it yourself, sell it, or turn it into other products to eat
or sell. Milk must be cooled quickly, or it will spoil. Raw milk has a shelf life of a week or a
little more. The shelf life of pasteurized milk is two to three weeks. Milk can be processed in-
to other products to help preserve it. Farmers selling milk conventionally often contract to
market their milk through a milk marketing cooperative. More than 85 percent of milk in the
United States is marketed through milk marketing cooperatives, which may bottle or process
the milk themselves under a farmer-owned brand (one you may know is Land-O-Lakes butter)
or sell the bulk milk to private processing companies that will package it as fluid milk or other
products and sell it around the country. These farmers pump their milk into a bulk tank. Con-
tracted milk haulers collect from these bulk tanks at least every other day.
Conventionally sold milk is always pasteurized. Pasteurization is the process of heating milk
to kill bacteria. There are three main methods of pasteurization:
• Batch pasteurization: This old-school method of pasteurization involves heating milk in
a vat to 145 degrees F and maintaining the heat for 30 minutes. Batch pasteurization is
used on milk that will be made into cheese, yogurt, and other value-added products.
• High Temperature/Short Time (HTST) pasteurization: Milk is heated to least 161 de-
grees F for at least 15 seconds. This is the most common method used in the United
States.
• Ultrapasteurization (UHT): Milk is heated to 280 degrees F for two seconds.
If milk is kept unopened after UHT, it does not have to be refrigerated for up to three months
and can be shipped warm.
Many on-farm bottling dairies pasteurize their milk because many states require it by law.
These dairies can pasteurize their products on the farm using a pasteurizing machine. The
HTST method usually is preferred because it is quicker than batch pasteurizing but does not
kill all bacteria — harmful or beneficial — the way ultrapasteurization does. You can buy pas-
teurizers from specialty dairy suppliers, as small as 2 gallons or as big as 300 gallons. You
also could pasteurize milk on your stove if you cook it at the right time and temperature.
Conventionally sold milk also is homogenized , which means a machine is used to break up
fat globules into small pieces so the cream will not rise to the top. Many dairy farmers choose