Abstract
The effect of the air-containing part of food packages on the location of the minimum Fo value was investigated. A 6%
gelatinized starch liquid was packed into a cylindrical cup also containing air, and the temperature was measured at six
points on the central vertical axis during thermal processing at 120 °C for 30 minutes. As a result, the position where the
Fo value was at a minimum was found to be closer to the air-containing part than to the geometric center of the cylinder.
When the temperature curves at each position were analyzed using the delay time (δ) of the ATS method, it was confirmed
that the minimum Fo value occurred where the temperature rise was slow and the cooling was fast. These minimum Fo
values were approximately 10% to 15% of the Fo value at the geometric center position. It is thus necessary to consider
the risks of an inadequate thermal treatment due to assuming an incorrect temperature measurement location by not
taking air pockets into account.
https://ror.org/03pjf9v33 
