Balancing Food Safety, Quality, and Yield
By: Sanghyup Jeong and Bradley Marks
Our daily life is full of problems that require decisions and choices.
Some problems are simple, but some are too complex to get nicely-fit
answers, because too many variables and factors influence the problem.
Optimization is a technique to solve complex problems occurring in our
daily life, finances, science, and engineering. Optimization can be
considered as the ultimate stage of most technical developments. Optimization
is the process of fine-tuning a system to get the best results. Without
the optimization process, the capabilities of a system cannot be explored
comprehensively, which can result in loss of valuable opportunities
for process improvement. As a part of decision support systems, optimization
techniques provide critical information for various problems.
In the case of food processing and manufacturing, an important optimization
challenge is finding processing conditions that simultaneously ensure
safety, meet quality criteria, and maximize the processing yield (and
therefore economic returns). It is difficult/impossible to find these
best conditions solely by experience when operating commercial ovens
in food manufacturing systems (Figure 1), because there are multiple
control variables (e.g., temperature, humidity, impingement velocity,
and cooking duration) affecting the outcome. In addition, many food
processing operations, such as cooking meat patties, are very complex
phenomena to express analytically. Therefore, it is not surprising that
most studies of optimization have been devoted to relatively simple
problems that have just one or two control variables (e.g., retorts
for canned foods).

Figure 1. JSO-IV Jet Stream Oven (Stein DSI,
FMC FoodTech, Sandusky, Ohio). |
Our recent (and ongoing) study has been building a foundation for process
optimization of meat patty cooking in moist air impingement oven systems,
which is very complex problem. The goal is to maximize processing yield,
which directly relates to economic return. However, this must be accomplished
within the context of: (a) regulatory constraints specifying the target
level of Salmonella inactivation, and (b) target limitations for quality
(e.g., surface color). To accomplish the above objectives, a mathematical
model for the cooking process (heat transfer, moisture transfer, fat
transfer, microbial inactivation, and color changes) was developed,
and a computer program was written to numerically solve the model. Artificial
neural network models and various global optimization techniques (genetic
algorithm, simulated annealing, and ICRS/DS) were then combined and
evaluated, in terms of the potential for these techniques to find the
optimal conditions for existing oven configurations (e.g., single- or
double-stage systems) and for the theoretically best (i.e., “future
generation”) configurations (Figure 2).

Figure 2. Example of optimal dynamic control
profiles for moist air impingement cooking system. |
The results of this project have shown that it is feasible to apply
optimization techniques to complex food processing operations with multiple
control variables. However, the specific results (e.g., maximum possible
yield) are highly dependent on the various components of the cooking
model (e.g., surface color) and the constraints applied to the problem.
Now, based on these discoveries, we will: (a) continue to refine the
optimization strategies for these types of complex food processing operations,
and (b) seek to investigate and validate practical solutions for commercial
meat cooking systems.
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