embodying their expertise in the form of rules a computer can apply.
One expert system, developed at the UK’s Flour Milling and Baking
Research Association, predicts the mould-free shelf life of bakery pro-
ducts. Hereawand temperature are the principal determinants of shelf-
life and previous storage trials have shown that, at a given temperature,
there is a linear relationship between the logarithm of the mould-free
shelf-life and theaw, expressed as equilibrium relative humidity (ERH).
For example, at 27 1 C:
log 10 mould-free shelf-life¼ 6 : 42 ð 0 : 0647 ERHÞð 3 : 34 ÞThe user is led through a series of screen menus, to choose a product
type, and input the ingredients, their relative amounts, the weight loss
during processing and the storage temperature. The programme then
calculates the ERH of the product and uses the appropriate isotherm to
calculate the mould-free shelf-life.
62 Factors Affecting the Growth and Survival of Micro-organisms in Foods