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Estimation of sterilizing values of processes as applied to canned foods. I.—Packs heating by conduction
Author(s) -
Gillespy T. G.
Publication year - 1951
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740020303
Subject(s) - retort , thermal conduction , value (mathematics) , degree (music) , heat resistance , mathematics , sterility , volume (thermodynamics) , d value , thermodynamics , mechanics , physics , chemistry , statistics , materials science , food science , biology , botany , composite material , organic chemistry , acoustics
The F value of a heating process as applied to a can of food is defined as the time in minutes at 250° F., assuming the whole can to be raised instantaneously to this temperature and cooled instantaneously to a sub‐lethal temperature afterwards, that would give the same degree of sterility as the process to be valued. The implications of the term ‘degree of sterility’ are discussed. Equations are developed and tables are given, applicable to pure conduction packs only, for estimating the F value of a process for a small finite volume at the centre of a cylindrical can. Such a value has hitherto been used to represent the F value for the whole can. It is here designated the F c value. The effects of the relative dimensions of the can, of pre‐processing procedures and of the coming‐up time of the retort are considered. The F c value is independent of the absolute heat resistance of the organisms to be killed, assuming the same temperature‐time relationship. A method is presented for estimating the F value for the whole can from the F c value. The F value is shown to vary with the heat resistance of the organisms for which the degree of sterility attained is defined.