Type
Temperature
Time
Vat or batch (holding method)..........................................145F (63C)......30 min
High-temperature, short-time (HTST)
(continuous flow)............................................................161F (72C).......15 sec
Higher-heat, shorter-time (HHST)
(continuous flow)............................................................191F (88.5C)...1.0 sec
194F (90C)......0.5 sec
201F (94C)......0.1 sec
204F (96C)......0.05 sec
212F (100C)....0.01 sec
Aseptically processed (UHT milk)
(continuous flow)...........................................................280 - 302F
(138 - 150C)......2 to 5 sec
Table 1-1. Pasturizing temperature/time requirements.
1-18. VAT OR BATCH PASTEURIZER
Vat or batch pasteurization is the process of heating milk in a vat or holding type
pasteurizer and is primarily used in small dairy plants or for processing by-products and
specialty products. The vat pasteurizer (see figure 1-1) consists of a jacketed vat that is
capable of maintaining the temperatures and holding times required for pasteurization.
A properly designed vat will protect the product from contamination and be equipped
with leak-protector inlet/outlet valves, a recording thermometer, an indicating
thermometer, an air space thermometer, and an agitator. An air space heater is
normally included also. During operation of the vat pasteurizer, the product may be
heated in the vat or partially/totally preheated prior to filling the vat. In any event, it is
critical that the holding time of 30 minutes commences after the minimum temperature
has been reached and the filling of the vat has been completed.
MD0715
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