Fundamental Food Microbiology, Third Edition - Fuad Fathir

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APPENDIX B
Predictive Modeling of Microbial Growth
in Food
I. IMPORTANCE
Every year, more than 12,000 new food products are introduced to U.S. consumers
in addition to the existing more than 100,000 food items. Some of these products
obviously have limited shelf life because of the possibility of microbial growth under
the conditions in which they are stored and handled following production. The initial
microbial population in many of these products may include both spoilage and
pathogenic types. To ensure stability and safety, it is important that proper control
measures are used to prevent growth of the microorganisms from the time of production
to the time of consumption of these products. 1,2
Among the thousands of new products marketed every year, some are definitely
produced to satisfy consumers looking for foods that are healthy, natural, low-fat,
low-salt, tasty, convenient, do not contain harsh preservatives, are not given harsh
treatment, have long storage life, and are safe. To produce these new types of foods
(such as the new-generation refrigerated foods) with desirable safety, stability, and
acceptance quality, the influence of many parameters, such as different ingredients
at different concentrations under different processing and storage conditions and at
different A w, pH and other intrinsic and extrinsic factors, on microbial growth and
destruction in foods has to be determined.
It is almost impossible to conduct such microbiological studies for each product
by the methods traditionally used to ensure safety and stability of food products.
However, with the aid of computers, mathematical models can be developed to
determine the influence of combinations of several parameters on microbial growth.
Although they may not be accurate, they can be effective to obtain first-hand
information very rapidly, helpful to eliminate many of the less important possibilities,
and select a few that appear more promising. This information can then be
used to conduct a modest traditional study that is feasible both experimentally and
economically.