MODELING, MONITORING AND CONTROL STRATEGIES FOR HIGH-TEMPERATURE SHORT-TIME PASTEURIZATION SYSTEMS - 3 - STATISTICAL MONITORING OF PRODUCT LETHALITY AND PROCESS SENSOR RELIABILITY
A. Negiz et al., MODELING, MONITORING AND CONTROL STRATEGIES FOR HIGH-TEMPERATURE SHORT-TIME PASTEURIZATION SYSTEMS - 3 - STATISTICAL MONITORING OF PRODUCT LETHALITY AND PROCESS SENSOR RELIABILITY, Food control, 9(1), 1998, pp. 29-47
Statistical process monitoring (SPM) is used in food processing indust
ries to improve productivity and product quality. SPM can also provide
information to operators on how close a process is to non-compliance
to product safety limits, and carry out periodic checks of sensor accu
racy at high frequency. Traditional SPM tools such as Shewhart charts
are not appropriate for continuous food processes because of autocorre
lation in data. Four alternative SPM techniques are presented and appl
ied to high temperature short time (HTST) dairy pasteurization. The st
udy attempted to achieve compliance of the HTST process operation with
the recommended Pasteurized Milk Ordinance by providing a margin betw
een the alarm limits of the monitoring chart and the safety limits. Mo
nitoring of residuals and parameter change detection techniques ave us
ed for monitoring processes with autocorrelated variables. Hotelling's
T-2 and residuals of canonical variates techniques are used for monit
oring multivariable processes. (C) 1998 Elsevier Science Ltd. All righ
ts reserved.