Temperature distribution tests are normally performed to identify the colde
st location in batch retorts in order to design safe processes. This work p
resents an approach to analysing temperature variability by considering its
potential impact on lethality variability. The procedure is illustrated wi
th the analysis of a four basket water cascading retort in both static and
rotary modes, and is based on the numerical calculation of the F-values fro
m the experimental retort temperature histories, neglecting all other sourc
es of variability. The temperature profiles were monitored basket by basket
(thirty thermocouples in each basket, one at a time) and also in the whole
retort (twenty thermocouples in four baskets). The location of the coldest
point depended on whether only the heating phase or the complete cycle wer
e considered. Replicates indicated that batch to batch variability can be a
major factor.