Je. Schlesser et al., ACQUISITION, STORAGE, AND REVIEW OF SAFETY DATA FROM A COMMERCIAL SYSTEM FOR HIGH-TEMPERATURE, SHORT-TIME PASTEURIZATION, Journal of dairy science, 81(1), 1998, pp. 25-30
A high temperature, short time (HTST) pasteurization system was equipp
ed with electronic sensors; to determine the temperature, pressure, fl
ow rate, and position of the flow diversion valve. A computer for data
acquisition was wired to the sensors to monitor and to record process
ing conditions related to public health. The processing conditions wer
e stored in safety files on the hard drive of the computer, transferre
d weekly to a tape drive, and stored. The processing conditions of the
HTST system were monitored for 270 d to determine the accuracy and re
liability of the data acquisition system. The size of the HTST safety
fries ranged from 6.2 to 9.1 MB when the sensors were monitored every
second. The file size was reduced to <1.8 MB when the monitoring frequ
ency was increased to every 5 s. To determine accuracy, the temperatur
es recorded by the data acquisition system were compared with the temp
eratures recorded by an electronic recorder controller. To determine r
eliability, changes in the position of the flow diversion valve were e
xamined to identify process deviations and were compared with the even
t marker on circular charts. The review of the data file by the actual
time method was an effective alternative to the electronic recorder c
ontroller for monitoring the completeness of data in the safety files.
Offline review to determine reliability required approximately 10 min
/d of records.