A mathematical model was developed to correlate the four heat penetration parameters of 57 Stumbo�s tables (18,513 datasets) in\r\ncanned food: g (the difference between the retort and the coldest point temperatures in the canned food at the end of the heating\r\nprocess), fh/u (the ratio of the heating rate index to the sterilizing value), z (the temperature change required for the thermal\r\ndestruction curve to traverse one log cycle), and Jcc, (the cooling lag factor). The quantities g, z, and Jcc, are input variables for\r\npredicting fh/U, while z, Jcc and fh/U are input variables for predicting the value of g, which is necessary to calculate the heating\r\nprocess time B, at constant retort temperature, using Ball�s formula. The process time calculated using the g value obtained from\r\nthemathematical model closely followed the time calculated fromthe tabulated g values (rootmean square of absolute errors RMS\r\n= 0.567 min, average absolute error = 0.421 min with a standard deviation SD = 0.380 min). Because the mathematical model can\r\nbe used to predict the intermediate values of any combination of inputs, avoiding the storage requirements and the interpolation of\r\n57 Stumbo�s tables, it allows a quick and easy automation of thermal process calculations and to perform these calculations using a\r\nspreadsheet.
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