Canadian Quality Milk On-Farm Food Safety Program - Centre ...

Canadian Quality Milk
Introduction
Methods of milk storage have changed dramatically over the history of the dairy
industry. Modern technology has enabled producers to store milk temporarily on their
farms before shipping it to the processing plants. However, to be effective, the system
must work and milk must be cooled quickly and stored at a temperature greater than
0°C and less than or equal to 4°C to reduce bacterial growth. Monitoring the bulk tank
temperature can ensure that milk is stored safely and that the cooling equipment is
functioning properly.
6.1 COOLING AND STORAGE OF MILK
Under the HACCP-like system, cooling is one of the CCPs in milk production
(CCP2). Bacteria multiply rapidly when milk is stored over 4°C (40°F) or cooled too
slowly. Excessive bacteria counts and the presence of disease organisms in milk are
risks to human health. A producer can control the multiplication of bacteria effectively if
milk is cooled and stored properly.
Critical Control Point: Cooling and storing milk
Hazard: Biological: pathogenic bacteria
Critical Limit: Bulk tank temperature.
The 1 st milking must be cooled to 10°C or less within one hour
and to a temperature greater than 0°C and less than or equal to
4°C within two hours after milking and maintained at that
temperature. When subsequent milkings enter the tank, blend
temperature shall not rise above 10°C for longer than 15
consecutive minutes and milk shall be cooled to a temperature
greater than 0°C and less than or equal to 4°C within one hour
after milking and maintained at that temperature.
Milk cooling systems
include a cooling tank that
absorbs heat from the milk.
The heat is transported by
a refrigerant to a
refrigeration unit, where it
is dissipated.
Some systems also have
plate coolers which work to
reduce the temperature of
the milk before the milk
reaches the refrigeration
units. Plate coolers help
cool milk faster.
Control Measures: Check the temperature of the milk after each milking. Producers
must have an accurate, operating bulk tank thermometer or recording thermometer.
Producers must be able to demonstrate how they know that thermometers are accurate
and operating (e.g. annually calibrate thermometers).
Thermometer Calibration: thermometers can be simply calibrated by filling a glass with
ice and then filling it up with cold water. Immerse the thermometer in the ice water and
reposition it to read 0°C.
Proper cooling is critical for the maintenance of milk safety. Recommended cooling
guidelines (National Dairy Code – section 15) can be seen in Table 12.
6—2
June 2010